Journal articles
Williams CAP, Vlachopoulos D, Ubago-Guisade E, Barker AR, Metcalf B, Fatouros IG, Avoniti A, Knapp K, Gracia-Marco L (In Press). Determinants of bone outcomes in adolescent athletes at baseline: the PRO-BONE study. Medicine and Science in Sports and Exercise
Gracia Marco L, Vlachopoulos D, Barker AR, Williams CA, Knapp K, Metcalf BS (In Press). Effect of a program of short bouts of exercise on bone health in adolescents involved in different sports: the PRO-BONE study protocol.
BMC Public HealthAbstract:
Effect of a program of short bouts of exercise on bone health in adolescents involved in different sports: the PRO-BONE study protocol
Background: Osteoporosis is a skeletal disease associated with high morbidity, mortality and increased economic costs. Early prevention during adolescence appears to be one of the most beneficial practices. Exercise is an effective approach for developing bone mass during puberty, but some sports may have a positive or negative impact on bone mass accrual. Plyometric jump training has been suggested as a type of exercise that can augment bone, but its effects on adolescent bone mass have not been rigorously assessed. The aims of the PRO-BONE study are to: 1) longitudinally assess bone health and its metabolism in adolescents engaged in osteogenic (football), non-osteogenic (cycling and swimming) sports and in a control group, and 2) examine the effect of a 9 month plyometric jump training programme on bone related outcomes in the sport groups.
Methods/Design: This study will recruit 105 males aged 12-14 years who have participated in sport specific training for at least 3 hours per week during the last 3 years in the following sports groups: football (n=30), cycling (n=30) and swimming (n=30). An age-matched control group (n=15) that does not engage in these sports more than 3 hours per week will also be recruited. Participants will be measured on 5 occasions: 1) at baseline; 2) after 12 months of sport specific training where each sport group will be randomly allocated into two sub-groups: intervention group (sport + plyometric jump training) and sport group (sport only); 3) exactly after the 9 months of intervention; 4) 6 months following the intervention; 5) 12 months following the intervention. Body composition (dual energy X-ray absorptiometry, air displacement plethysmography and bioelectrical impedance), bone stiffness index (ultrasounds), physical activity (accelerometers), diet (24 h recall questionnaire), pubertal maturation (Tanner stage), physical fitness (cardiorespiratory and muscular) and biochemical markers of bone formation and resorption will be measured at each visit.
Discussion: the PRO-BONE study is designed to investigate the impact of osteogenic and non-osteogenic sports on bone development in adolescent males during puberty, and how a plyometric jump training programme is associated with body composition parameters.
Abstract.
Knapp KM, Welsman JR, Rowlands AV, MacLeod KM (In Press). Prolonged disuse osteopoenia 14 years post external fixation removal. Osteoporosis International
Knapp KM, Wright C, Clarke H, McAnulla SJ, Nightingale J (In Press). The academic radiography workforce: Age profile, succession planning and academic development. Radiography
Smith D, Knapp PK, Wright DC, Hollick DR (2023). Dual Energy X-Ray Absorptiometry (DXA) Extended Femur Scans to Support Opportunistic Screening for Incomplete Atypical Femoral Fractures: a Short Term in-vivo Precision Study. Journal of Clinical Densitometry, 26(2), 101352-101352.
Banfield LR, Knapp KM, Pilling LC, Melzer D, Atkins JL (2023). Hemochromatosis Genetic Variants and Musculoskeletal Outcomes: 11.5‐Year Follow‐Up in the <scp>UK</scp> Biobank Cohort Study.
JBMR PlusAbstract:
Hemochromatosis Genetic Variants and Musculoskeletal Outcomes: 11.5‐Year Follow‐Up in the UK Biobank Cohort Study
ABSTRACTThe iron overload disorder hemochromatosis is primarily caused by the homozygous HFE p.C282Y variant, but the scale of excess related musculoskeletal morbidity is uncertain. We estimated hemochromatosis‐genotype associations with clinically diagnosed musculoskeletal outcomes and joint replacement surgeries in the UK Biobank community cohort. A total of 451,143 European ancestry participants (40 to 70 years at baseline) were followed in hospital records (mean 11.5‐years). Cox proportional hazards models estimated HFE p.C282Y and p.H63D associations with incident outcomes. Male p.C282Y homozygotes (n = 1294) had increased incidence of osteoarthritis (n = 52, hazard ratio [HR]: 2.12 [95% confidence interval, CI: 1.61 to 2.80]; p = 8.8 × 10−8), hip replacement (n = 88, HR: 1.84 [95% CI: 1.49 to 2.27]; p = 1.6 × 10−8), knee replacement (n = 61, HR: 1.54 [95% CI: 1.20 to 1.98]; p = 8.4 × 10−4), and ankle and shoulder replacement, compared to males with no HFE mutations. Cumulative incidence analysis, using Kaplan–Meier lifetable probabilities demonstrated 10.4% of male homozygotes were projected to develop osteoarthritis and 15.5% to have hip replacements by age 75, versus 5.0% and 8.7% respectively without mutations. Male p.C282Y homozygotes also had increased incidence of femoral fractures (n = 15, HR: 1.72 [95% CI: 1.03 to 2.87]; p = 0.04) and osteoporosis (n = 21, HR: 1.71 [95% CI: 1.11 to 2.64]; p = 0.02), although the latter association was limited to those with liver fibrosis/cirrhosis diagnoses. Female p.C282Y homozygotes had increased incidence of osteoarthritis only (n = 57, HR: 1.46, [95% CI: 1.12 to 1.89]; p = 0.01). Male p.C282Y/p.H63D compound heterozygotes experienced a modest increased risk of hip replacements (n = 234, HR: 1.17 [95% CI: 1.02 to 1.33], p = 0.02), but this did not pass multiple testing corrections. In this large community cohort, the p.C282Y homozygote genotype was associated with substantial excess musculoskeletal morbidity in males. Wider HFE genotype testing may be justified, including in orthopedic clinics serving higher HFE variant prevalence populations. © 2023 the Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
Abstract.
Sayed M, Knapp KM, Fulford J, Heales C, Alqahtani SJ (2023). The principles and effectiveness of X-ray scatter correction software for diagnostic X-ray imaging: a scoping review. European Journal of Radiology, 158, 110600-110600.
Monteyne AJ, Coelho MOC, Murton AJ, Abdelrahman DR, Blackwell JR, Koscien CP, Knapp KM, Fulford J, Finnigan TJA, Dirks ML, et al (2023). Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults.
J Nutr,
153(6), 1680-1695.
Abstract:
Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults.
BACKGROUND: it remains unclear whether non-animal-derived dietary protein sources (and therefore vegan diets) can support resistance training-induced skeletal muscle remodeling to the same extent as animal-derived protein sources. METHODS: in Phase 1, 16 healthy young adults (m = 8, f = 8; age: 23 ± 1 y; BMI: 23 ± 1 kg/m2) completed a 3-d dietary intervention (high protein, 1.8 g·kg bm-1·d-1) where protein was derived from omnivorous (OMNI1; n = 8) or exclusively non-animal (VEG1; n = 8) sources, alongside daily unilateral leg resistance exercise. Resting and exercised daily myofibrillar protein synthesis (MyoPS) rates were assessed using deuterium oxide. In Phase 2, 22 healthy young adults (m = 11, f = 11; age: 24 ± 1 y; BMI: 23 ± 0 kg/m2) completed a 10 wk, high-volume (5 d/wk), progressive resistance exercise program while consuming an omnivorous (OMNI2; n = 12) or non-animal-derived (VEG2; n = 10) high-protein diet (∼2 g·kg bm-1·d-1). Muscle fiber cross-sectional area (CSA), whole-body lean mass (via DXA), thigh muscle volume (via MRI), muscle strength, and muscle function were determined pre, after 2 and 5 wk, and postintervention. OBJECTIVES: to investigate whether a high-protein, mycoprotein-rich, non-animal-derived diet can support resistance training-induced skeletal muscle remodeling to the same extent as an isonitrogenous omnivorous diet. RESULTS: Daily MyoPS rates were ∼12% higher in the exercised than in the rested leg (2.46 ± 0.27%·d-1 compared with 2.20 ± 0.33%·d-1 and 2.62 ± 0.56%·d-1 compared with 2.36 ± 0.53%·d-1 in OMNI1 and VEG1, respectively; P < 0.001) and not different between groups (P > 0.05). Resistance training increased lean mass in both groups by a similar magnitude (OMNI2 2.6 ± 1.1 kg, VEG2 3.1 ± 2.5 kg; P > 0.05). Likewise, training comparably increased thigh muscle volume (OMNI2 8.3 ± 3.6%, VEG2 8.3 ± 4.1%; P > 0.05), and muscle fiber CSA (OMNI2 33 ± 24%, VEG2 32 ± 48%; P > 0.05). Both groups increased strength (1 repetition maximum) of multiple muscle groups, to comparable degrees. CONCLUSIONS: Omnivorous and vegan diets can support comparable rested and exercised daily MyoPS rates in healthy young adults consuming a high-protein diet. This translates to similar skeletal muscle adaptive responses during prolonged high-volume resistance training, irrespective of dietary protein provenance. This trial was registered at clinicaltrials.gov as NCT03572127.
Abstract.
Author URL.
Assiri R, Knapp K, Fulford J, Chen J (2022). Correlation of the quantitative methods for the measurement of bone uptake and plasma clearance of 18F-NaF using positron emission tomography. Systematic review and meta-analysis.
Eur J Radiol,
146Abstract:
Correlation of the quantitative methods for the measurement of bone uptake and plasma clearance of 18F-NaF using positron emission tomography. Systematic review and meta-analysis.
PURPOSE: 18F-NaF PET is valuable for detecting bone metabolism through osteoblastic activity in the assessment of bone disease. Hawkins, Patlak, and standardised uptake value (SUV) are the most common quantitative measurements used to evaluate bone metabolism. This systematic review evaluates the correlation between quantitative positron emission tomography (PET) methods and to compare their precision. METHODS: a systematic search in Medline, PubMed, SCOPUS, and Web of Science was undertaken to find relevant papers published from 2000. All studies with human adults undergoing 18F-NaF PET, PET/CT, or PET/MRI were included except for subjects diagnosed with non-diffuse metabolic bone disease or malignancy. Quality Assessment Tool for Studies of Diverse Designs (QATSDD) was used to assess risk of bias. A qualitative review and meta-analysis using Hedges random-effect model was used producing summary size effects of the correlation between methods in healthy and unhealthy bone sites and assessing study heterogeneity. RESULTS: 228 healthy and unhealthy participants were included across 12 studies resulted from the systematic search. One-third of studies had a moderate quality percentage while the rest had relatively high quality. The pooled correlation coefficient in meta-analysis showed a high correlation of more than 0.88 (0.71-1.05. 95 %CI) between SUV and Hawkins and more than 0.96 (0.88-1.03. 95 %CI) between Patlak and Hawkins within all subgroups, suggesting all methods yield similar results in healthy and unhealthy bone sites. SUV has the lowest precision error followed by Patlak while Hawkins method showed the highest precision error. CONCLUSION: Patlak is the best within research and SUV is better within clinical practice.
Abstract.
Author URL.
Alqahtani SJ, Knapp KM (2022). Imaging patients with obesity. Journal of Medical Radiation Sciences, 69(1), 3-4.
Hayre CM, Knapp KM (2022). Leading radiography research to deliver clinical outcomes. Journal of Medical Imaging and Radiation Sciences, 53(4), S35-S37.
Alghamdi F, Owen R, Ashton REM, Obotiba AD, Meertens RM, Hyde E, Faghy MA, Knapp KM, Rogers P, Strain WD, et al (2022). Post-acute COVID syndrome (long COVID): What should radiographers know and the potential impact for imaging services. Radiography, 28, S93-S99.
Hu J, Gundry M, Zheng K, Zhong J, Hourigan P, Meakin JR, Winlove CP, Toms AD, Knapp KM, Chen J, et al (2022). The biomechanics of metaphyseal cone augmentation in revision knee replacement.
J Mech Behav Biomed Mater,
131Abstract:
The biomechanics of metaphyseal cone augmentation in revision knee replacement.
The demand for revision knee replacement (RKR) has increased dramatically with rising patient life expectancy and younger recipients for primary TKR. However, significant challenges to RKR arise from osseous defects, reduced bone quality, potential bone volume loss from implant removal and the need to achieve implant stability. This study utilizes the outcomes of an ongoing RKR clinical trial using porous metaphyseal cones 3D-printed of titanium, to investigate 1) bone mineral density (BMD) changes in three fixation zones (epiphysis, metaphysis, and diaphysis) over a year and 2) the biomechanical effects of the cones at 6 months post-surgery. It combines dual-energy x-ray absorptiometry (DXA), computed tomography (CT) with patient-specific based finite element (FE) modelling. Bone loss (-0.086 ± 0.05 g/cm2) was found in most patients over the first year. The biomechanical assessment considered four different loading scenarios from standing, walking on a flat surface, and walking downstairs, to a simulated impact of the knee. The patient-specific FE models showed that the cones marginally improved the strain distribution in the bone and shared the induced load but played a limited role in reducing the risks of bone fracture or cement debonding. This technique of obtaining real live data from a randomized clinical trial and inserting it into an in-silico FE model is unique and innovative in RKR research. The tibia RKR biomechanics examined open up further possibilities, allowing the in-silico testing of prototypes and implant combinations without putting patients at risk as per the recommended IDEAL framework standards. This process with further improvements could allow rapid innovation, optimization of implant design, and improve surgical planning.
Abstract.
Author URL.
Knapp KM, Venner S, McNulty JP, Rainford LA (2022). The challenges, coping mechanisms, and recovery from the initial waves of the COVID-19 pandemic among academic radiographers. Radiography, 28, S35-S40.
Knapp KM, Venner S, McNulty JP, Rainford LA (2022). The risk of burnout in academic radiographers during the COVID-19 pandemic. Radiography, 28(4), 1010-1015.
Hudson D, Knapp K, Benwell M (2021). An evaluation of MRI lumbar spine scans within a community-based diagnostic setting.
Musculoskeletal Care,
19(3), 384-395.
Abstract:
An evaluation of MRI lumbar spine scans within a community-based diagnostic setting
Background: with an ongoing move towards more management of patients within the community setting, demand for magnetic resonance imaging (MRI) is increasing and commonly used in lower back conditions. There is well recorded overuse of MRI in this scenario which goes against evidence-based practice and adds to rising healthcare costs. Methods: the study was a retrospective review of lumbar spine MRI scans performed within a community-based setting over an 18-month period. The review took a randomised purposive sample of patients (n = 450); looking at adherence to, and relevance of, guidelines in managing lower back conditions. Data extracted provided information on demographics and prevalence of clinical presentation and report observations. Results: There is variation in practice and utlisation of MRI with this patient group which warrants further exploration. Results support inappropriate use, lacking adherence to guidelines and pathways, leading to unnecessary imaging. 46% of referrals were considered clinically justified with 38% of report findings considered abnormal and of clinical relevance. Chi-square and binomial logistic regression were used to assess the significance and relationship of any factors on referral justification and report outcome. No difference was found between type of referrer, with patient age and leg symptoms being significant factors. Conclusion: the study highlights the opportunity to integrate better referral criteria to improve referral quality, its suitability and the relevance of final reports. In the current climate this would help manage appropriate use of imaging resources during the post COVID-19 pandemic recovery phase, as well as support recommendations regarding diagnostic reform and a move towards more community-based diagnostics.
Abstract.
Malamateniou C, Knapp KM, Pergola M, Woznitza N, Hardy M (2021). Artificial intelligence in radiography: Where are we now and what does the future hold?. Radiography, 27, S58-S62.
Meertens R, Knapp KM, Strain WD, Casanova F, Ball S, Fulford J, Thorn C (2021). In vivo Measurement of Intraosseous Vascular Haemodynamic Markers in Human Bone Tissue Utilising Near Infrared Spectroscopy.
Frontiers in Physiology,
12Abstract:
In vivo Measurement of Intraosseous Vascular Haemodynamic Markers in Human Bone Tissue Utilising Near Infrared Spectroscopy
Objective:Poor vascular health is associated with reduced bone strength and increased risk of fragility fracture. However, direct measurement of intraosseous vascular health is difficult due to the density and mineral content of bone. We investigated the feasibility of using a commercially available continuous wave near infrared spectroscopy (NIRS) system for the investigation of vascular haemodynamics in human bonein vivo.Approach:An arterial occlusion (AO) protocol was developed for obtaining haemodynamic measurements of the proximal tibia and lateral calf, including assessment of the protocol’s intra operator reproducibility. For 36 participants, intraosseous haemodynamics derived by NIRS were compared to alternative tests of bone health based on dual x-ray absorptiometry (DXA) testing and MRI.Main Results:Near infrared spectroscopy markers of haemodynamics of the proximal tibia demonstrated acceptable reproducibility, comparable with reproducibility assessments of alternative modalities measuring intraosseous haemodynamics, and the use of NIRS for measuring muscle. Novel associations have been demonstrated between haemodynamic markers of bone measured with NIRS and body composition and bone mineral density (BMD) measurements obtained with both DXA and MRI.Significance:Near infrared spectroscopy provides inexpensive, non-invasive, safe, and real time data on changes in oxygenated and deoxygenated haemoglobin concentration in bone at the proximal tibia. This study has demonstrated the potential for NIRS to contribute to research investigating the pathophysiological role of vascular dysfunction within bone tissue, but also the limitations and need for further development of NIRS technology.
Abstract.
Knapp KM, Courtier N (2021). The future role of radiographers.
Radiography (Lond),
27 Suppl 1, S1-S2.
Author URL.
Rainford LA, Zanardo M, Buissink C, Decoster R, Hennessy W, Knapp K, Kraus B, Lanca L, Lewis S, Mahlaola TB, et al (2021). The impact of COVID-19 upon student radiographers and clinical training.
Radiography (Lond),
27(2), 464-474.
Abstract:
The impact of COVID-19 upon student radiographers and clinical training.
INTRODUCTION: to investigate student clinical placement concerns and opinions, during the initial COVID-19 pandemic outbreak and to inform educational institution support planning. METHODS: Between mid-June to mid-July 2020, educational institutions from 12 countries were invited to participate in an online survey designed to gain student radiographer opinion from a wide geographical spread and countries with varying levels of COVID-19 cases. RESULTS: 1277 respondents participated, of these 592 had completed clinical placements during January to June 2020. Accommodation and cohabiting risks were identified as challenging, as was isolation from family, travel to clinical placements, and to a lesser extent childcare. Students stated they had been affected by the feeling of isolation and concerns about the virus whilst on placement. Overall 35.4% of all respondents were 'Not at all worried' about being a radiographer, however, 64.6% expressed varying levels of concern and individual domestic or health situations significantly impacted responses (p ≤ 0.05). Year 4 students and recent graduates were significantly more likely to be 'Not worried at all' compared to Year 2 and 3 students (p ≤ 0.05). The need for improved communication regarding clinical placements scheduling was identified as almost 50% of students on clinical placements between January to June 2020 identified the completion of assessments as challenging. Furthermore, only 66% of respondents with COVID-19 imaging experience stated being confident with personal protective equipment (PPE) use. CONCLUSION: Student radiographers identified key challenges which require consideration to ensure appropriate measures are in place to support their ongoing needs. Importantly PPE training is required before placement regardless of prior COVID-19 imaging experience. IMPLICATIONS FOR PRACTICE: As the next academic year commences, the study findings identify important matters to be considered by education institutions with responsibility for Radiography training and as students commence clinical placements during the on-going global COVID-19 pandemic.
Abstract.
Author URL.
Malik H, Appelboam A, Taylor G, Wood D, Knapp K (2020). 71 Ultrasound directed reduction of Colles’ type distal radial fractures in ED (UDiReCT): a feasibility randomized controlled trial. Emergency Medicine Journal, 37(12), 835-836.
Reyes-Aldasoro CC, Ngan KH, Ananda A, d'Avila Garcez A, Appelboam A, Knapp KM (2020). Geometric semi-automatic analysis of radiographs of Colles' fractures.
PLoS One,
15(9).
Abstract:
Geometric semi-automatic analysis of radiographs of Colles' fractures.
Fractures of the wrist are common in Emergency Departments, where some patients are treated with a procedure called Manipulation under Anaesthesia. In some cases, this procedure is unsuccessful and patients need to revisit the hospital where they undergo surgery to treat the fracture. This work describes a geometric semi-automatic image analysis algorithm to analyse and compare the x-rays of healthy controls and patients with dorsally displaced wrist fractures (Colles' fractures) who were treated with Manipulation under Anaesthesia. A series of 161 posterior-anterior radiographs from healthy controls and patients with Colles' fractures were acquired and analysed. The patients' group was further subdivided according to the outcome of the procedure (successful/unsuccessful) and pre- or post-intervention creating five groups in total (healthy, pre-successful, pre-unsuccessful, post-successful, post-unsuccessful). The semi-automatic analysis consisted of manual location of three landmarks (finger, lunate and radial styloid) and automatic processing to generate 32 geometric and texture measurements, which may be related to conditions such as osteoporosis and swelling of the wrist. Statistical differences were found between patients and controls, as well as between pre- and post-intervention, but not between the procedures. The most distinct measurements were those of texture. Although the study includes a relatively low number of cases and measurements, the statistical differences are encouraging.
Abstract.
Author URL.
Connolly LJ, Scott S, Morencos CM, Fulford J, Jones AM, Knapp K, Krustrup P, Bailey SJ, Bowtell JL (2020). Impact of a novel home-based exercise intervention on health indicators in inactive premenopausal women: a 12-week randomised controlled trial.
Eur J Appl Physiol,
120(4), 771-782.
Abstract:
Impact of a novel home-based exercise intervention on health indicators in inactive premenopausal women: a 12-week randomised controlled trial.
PURPOSE: This study tested the hypothesis that a novel, audio-visual-directed, home-based exercise training intervention would be effective at improving cardiometabolic health and mental well-being in inactive premenopausal women. METHODS: Twenty-four inactive premenopausal women (39 ± 10 years) were randomly assigned to an audio-visual-directed exercise training group (DVD; n = 12) or control group (CON; n = 12). During the 12-week intervention period, the DVD group performed thrice-weekly training sessions of 15 min. Training sessions comprised varying-intensity movements involving multiplanar whole-body accelerations and decelerations (average heart rate (HR) = 76 ± 3% HRmax). CON continued their habitual lifestyle with no physical exercise. A series of health markers were assessed prior to and following the intervention. RESULTS: Following the DVD intervention, HDL cholesterol (pre: 1.83 ± 0.45, post: 1.94 ± 0.46 mmol/L) and mental well-being, assessed via the Warwick Edinburgh Mental Well-Being Scale, improved (P 0.05). There were no pre-post intervention changes in any of the outcome variables in the CON group (P > 0.05). CONCLUSION: the present study suggests that a novel, audio-visual-directed exercise training intervention, consisting of varied-intensity movements interspersed with spinal and lower limb mobility and balance tasks, can improve [HDL cholesterol] and mental well-being in premenopausal women. Therefore, home-based, audio-visual-directed exercise training (45 min/week) appears to be a useful tool to initiate physical activity and improve aspects of health in previously inactive premenopausal women.
Abstract.
Author URL.
McAnulla SJ, Ball SE, Knapp KM (2020). Understanding student radiographer attrition: Risk factors and strategies. Radiography, 26(3), 198-204.
Bleiker J, Knapp K, Morgan-Trimmer S, Hopkins S (2020). What Medical Imaging Professionals Talk About When They Talk About Compassion. Journal of Medical Imaging and Radiation Sciences, 51(4), S44-S52.
Fox DL, Rimes SJ, Knapp KM, Meertens RM (2019). Computed tomography colonography: Radiographer independent preliminary clinical evaluation for intraluminal pathology.
Radiography,
25(4), 359-364.
Abstract:
Computed tomography colonography: Radiographer independent preliminary clinical evaluation for intraluminal pathology
Introduction: We evaluated the reporting competency of radiographers providing preliminary clinical evaluations (PCE) for intraluminal pathology of computed tomography colonography (CTC). Method: Following validation of a suitable tool, audit was undertaken to compare radiographer PCE against radiology reports. A database was designed to capture radiographer and radiologist report data. The radiographer's PCE of intraluminal pathology was given a score, the “pathology discrepancy and significance” (PDS) score based on the pathology present, any discrepancy between the PCE and the final report, and the significance of that discrepancy on the management of the patient. Agreement was assessed using percentage agreement and Kappa coefficient. Significant discrepancies between findings were compared against endoscopy and pathology reports. Results: There was agreement or insignificant discrepancy between the radiographer PCE and the radiology report for 1736 patients, representing 97.0% of cases. There was a significant discrepancy between findings in 2.8% of cases and a major discrepancy recorded for 0.2% of cases. There was a 98.4% agreement in the 229 cases where significant pathologies were present. Conclusion: from a database of 1815 studies acquired over three years and representing work done in a clinical environment, this study indicates a potential for trained radiographers to provide a PCE of intraluminal pathology.
Abstract.
Heales CJ, Summers IR, Fulford J, Knapp K, Winlove CP (2019). Investigation of changes in bone density and chemical composition associated with bone marrow oedema-type appearances in magnetic resonance images of the equine forelimb. BMC Musculoskeletal Disorders, 20, 330-330.
Bleiker J, Morgan-Trimmer S, Knapp K, Hopkins S (2019). Navigating the maze: Qualitative research methodologies and their philosophical foundations.
Radiography,
25, S4-S8.
Abstract:
Navigating the maze: Qualitative research methodologies and their philosophical foundations
Objectives: One of the three objectives of the Society and College of Radiographers is the promotion and dissemination of research in radiography and radiotherapy. This article aims to assist in the production of high standard research by explaining how transparency in reporting the underpinning philosophical basis of a qualitative study can be achieved in addition to the more customary descriptions of how data were collected and analysed. Key findings: Unlike their quantitative equivalent, qualitative research methodologies are less well understood and reported in radiography research, in particular the philosophical and epistemological assumptions which underpin the methods used. Conclusion: Demonstrating consistency between the philosophical position taken and the methods used within a study is an important aspect of research quality. Implications for practice: Qualitative research can offer valuable insights into the social, organisational, behavioural and interpersonal aspects of medical imaging practice. These may include wellbeing, attitudes, perceptions and beliefs, leadership, management practices, education, professionalism and a wide range of issues around patients' experiences during medical imaging. Patient care and outcomes can be positively impacted as a result of acquiring these insights.
Abstract.
Meakin JR, Ames RM, Jeynes JCG, Welsman J, Gundry M, Knapp K, Everson R (2019). The feasibility of using citizens to segment anatomy from medical images: Accuracy and motivation. PLOS ONE, 14(10), e0222523-e0222523.
Gundry M, Knapp K, Meertens R, Meakin JR (2018). Computer-aided detection in musculoskeletal projection radiography: a systematic review.
Radiography,
24, 165-174.
Abstract:
Computer-aided detection in musculoskeletal projection radiography: a systematic review
Objectives: to investigated the accuracy of computer-aided detection (CAD) software in musculoskeletal projection radiography via a systematic review. Key findings: Following selection screening, eligible studies were assessed for bias, and had their study characteristics extracted resulting in 22 studies being included. of these 22 three studies had tested their CAD software in a clinical setting; the first study investigated vertebral fractures, reporting a sensitivity score of 69.3% with CAD, compared to 59.8% sensitivity without CAD. The second study tested dental caries diagnosis producing a sensitivity score of 68.8% and specificity of 94.1% with CAD, compared to sensitivity of 39.3% and specificity of 96.7% without CAD. The third indicated osteoporotic cases based on CAD, resulting in 100% sensitivity and 81.3% specificity. Conclusion: the current evidence reported shows a lack of development into the clinical testing phase; however the research does show future promise in the variation of different CAD systems.
Abstract.
Hopkins SJ, Toms AD, Brown M, Appleboam A, Knapp KM (2018). Disuse osteopenia following leg fracture in postmenopausal women: Implications for HIP fracture risk and fracture liaison services.
Radiography,
24(2), 151-158.
Abstract:
Disuse osteopenia following leg fracture in postmenopausal women: Implications for HIP fracture risk and fracture liaison services
Introduction: Disuse osteopenia is a known consequence of reduced weight-bearing and has been demonstrated at the hip following leg injury but has not been specifically studied in postmenopausal women. Method: Bilateral DXA (GE Lunar Prodigy) bone mineral density (BMD) measurements were taken at the neck of femur (NOF), total hip region (TH) and lumbar spine in postmenopausal female groups comprising controls (N = 43), new leg fractures (#1yr) (N = 24). #>1yr were assessed at a single visit and the remaining groups at intervals over twelve months. Weight-bearing, function, 3-day pedometer readings, and pain levels were also recorded. Results: the #1yr scored significantly below controls in almost all key physical and functional outcomes demonstrating a long-term deficit in hip bone density on the ipsilateral side. Conclusion: the clinical significance of post-fracture reduction in hip BMD is a potential increased risk of hip fracture for a variable period that may be mitigated after return to normal function and weight-bearing. Improvement at 12 months in #1yr results indicating that long-term impairment in function and bone health may persist for some leg fracture patients. Unilateral bone loss could have implications for Fracture Liaison Services when assessing the requirement for medication post fracture.
Abstract.
Arnold J, Ewings P, Handel L, Langdon M, Powell H, Rhydderch-Evans Z, Stone W, Woodland S, Hoade L, Bleiker J, et al (2018). Fragile: Please handle with care. Radiography, 24, S9-S10.
Al Arif SMMR, Knapp K, Slabaugh G (2018). Fully automatic cervical vertebrae segmentation framework for X-ray images.
Computer Methods and Programs in Biomedicine,
157, 95-111.
Abstract:
Fully automatic cervical vertebrae segmentation framework for X-ray images
The cervical spine is a highly flexible anatomy and therefore vulnerable to injuries. Unfortunately, a large number of injuries in lateral cervical X-ray images remain undiagnosed due to human errors. Computer-aided injury detection has the potential to reduce the risk of misdiagnosis. Towards building an automatic injury detection system, in this paper, we propose a deep learning-based fully automatic framework for segmentation of cervical vertebrae in X-ray images. The framework first localizes the spinal region in the image using a deep fully convolutional neural network. Then vertebra centers are localized using a novel deep probabilistic spatial regression network. Finally, a novel shape-aware deep segmentation network is used to segment the vertebrae in the image. The framework can take an X-ray image and produce a vertebrae segmentation result without any manual intervention. Each block of the fully automatic framework has been trained on a set of 124 X-ray images and tested on another 172 images, all collected from real-life hospital emergency rooms. A Dice similarity coefficient of 0.84 and a shape error of 1.69 mm have been achieved.
Abstract.
Knapp KM, Meertens RM, Seymour R (2018). Imaging in osteoporosis: an update. Geriatric Medicine, 48, 10-12.
Alqahtani S, Wellbourn R, Meakin JR, Palfrey R, Rimes S, Thomson K, Knapp K (2018). Increased radiation dose and projected radiation-related lifetime cancer risk in patients with obesity due to projection radiography. Journal of Radiological Protection, 39
Rachuba S, Knapp K, Ashton L, Pitt M (2018). Streamlining pathways for minor injuries in emergency departments through radiographer-led discharge.
Operations Research for Health Care,
19, 44-56.
Abstract:
Streamlining pathways for minor injuries in emergency departments through radiographer-led discharge
Diagnostic imaging services are essential to the diagnosis pathway for many patients arriving at hospital emergency departments with a suspected fracture. Commonly, these patients need to be seen again by a doctor or emergency nurse practitioner after an X-ray image has been taken in order to finalise the diagnosis and determine the next stage in the patients’ pathway. Here, significant waiting times can accrue for these follow-up consultations after radiographic imaging although the vast majority of patients are discharged. Research evidence from pilot studies suggests that patients with minor appendicular injuries could be safely discharged by a suitably qualified radiographer directly after imaging thereby avoiding queues for repeated consultation. In this study, we model patient pathways through an emergency department (ED) at a hospital in the South West of England using process mapping, interviews with ED staff and discrete event simulation (DES). The DES model allowed us to compare the current practice at the hospital with scenarios using radiographer-led discharge of patients directly after imaging and assess the reduction in patients’ length of stay in ED. We also quantified trade-offs between the provision of radiographer-led discharge and its effects, i.e. reduction in waiting times and ED workload. Finally, we discuss how this decision support tool can be used to support understanding for patients and members of staff.
Abstract.
Vlachopoulos D, Barker AR, Ubago-Guisado E, Ortega FB, Krustrup P, Metcalf B, Castro Pinero J, Ruiz JR, Knapp KM, Williams CA, et al (2018). The effect of 12-month participation in osteogenic and non-osteogenic sports on bone development in adolescent male athletes. The PRO-BONE study.
J Sci Med Sport,
21(4), 404-409.
Abstract:
The effect of 12-month participation in osteogenic and non-osteogenic sports on bone development in adolescent male athletes. The PRO-BONE study.
OBJECTIVES: Research investigating the longitudinal effects of the most popular sports on bone development in adolescent males is scarce. The aim is to investigate the effect of 12-month participation in osteogenic and non-osteogenic sports on bone development. DESIGN: a 12-month study was conducted in adolescent males involved in football, swimming and cycling and compared with an active control group. METHODS: 116 adolescent males (13.1±0.1years at baseline): 37 footballers, 37 swimmers, 28 cyclists and 14 active controls were followed for 12 months. Bone mineral content (BMC) was measured by dual-energy X-ray absorptiometry, and bone stiffness was measured by quantitative ultrasound. Bone outcomes at 12 months were adjusted for baseline bone status, age, height, lean mass and moderate to vigorous physical activity. RESULTS: Footballers had higher improvement in adjusted BMC at the total body, total hip, shaft, Ward's triangle, legs and bone stiffness compared to cyclists (6.3-8.0%). Footballers had significantly higher adjusted BMC at total body, shaft and legs compared to swimmers (5.4-5.6%). There was no significant difference between swimmers and cyclists for any bone outcomes. Swimming and cycling participation resulted in non-significant lower bone development at most sites of the skeleton compared to controls (-4.3 to -0.6%). CONCLUSIONS: Football participation induces significantly greater improvements in BMC and bone stiffness over 12 months compared to cycling and swimming. CLINICAL TRIAL REGISTRATION: ISRCTN17982776.
Abstract.
Author URL.
Meertens RM, Casanova F, Knapp KM, Thorn C, Strain WD (2018). Use of Near-Infrared Systems for Investigations of Hemodynamics in Human in Vivo Bone Tissue: a Systematic Review. Journal of Orthopaedic Research
Bleiker J, Knapp KM, Morgan-Trimmer S, Hopkins SJ (2018). “It's what's behind the mask”: Psychological diversity in compassionate patient care.
Radiography,
24, S28-S32.
Abstract:
“It's what's behind the mask”: Psychological diversity in compassionate patient care
Introduction: the Francis Report recommended an increased focus on compassion in healthcare, and recognition and non-judgmental acceptance of diversity is fundamental in compassionate patient care. The aim of this study was to achieve a wider understanding of diversity that includes individual patient needs, expectations, perceptions and feelings during diagnostic imaging. Methods: Using thirty-four semi-structured interviews with individual patients, this qualitative study explored their experiences of undergoing diagnostic radiography examinations and asked what compassionate care meant to them and how it is perceived and manifested in the brief, task-focussed and highly technical diagnostic projection imaging encounter. Data were analysed using Thematic Analysis. Results: Four key themes were identified from the analysis; these were: feelings and vulnerability; hidden emotions; professionalism and valued qualities and communication. Conclusion: Diversity is defined not only in terms of socio-cultural differences but also psychological ones, i.e. individual emotional and attitudinal characteristics, some of which may be consciously or unconsciously concealed. In order that patients are treated equitably and all of their care needs met, recommendations include a broader focus in education and training to include adapting communication skills and techniques in perception and expression of non-verbal cues. Further research into the pressures specific to the time-pressured, task-focussed, highly technical and rapid turnover environment of projection imaging radiography and how this impacts upon compassionate patient care would make a useful contribution to the field.
Abstract.
Gundry M, Hopkins S, Knapp K (2017). A Review on Bone Mineral Density Loss in Total Knee Replacements Leading to Increased Fracture Risk.
Clinical Reviews in Bone and Mineral Metabolism,
15(4), 162-174.
Abstract:
A Review on Bone Mineral Density Loss in Total Knee Replacements Leading to Increased Fracture Risk
The link between low bone mineral density (BMD) scores leading to greater fracture risk is well established in the literature; what is not fully understood is the impact of total knee replacements/revisions or arthroplasties on BMD levels. This literature review attempts to answer this question. Several different databases using specific key terms were searched, with additional papers retrieved via bibliographic review. Based on the available evidence, total knee replacements/revisions and arthroplasties lower BMD and thus increase fracture risk. This review also addresses the possible implications of this research and possible options to reduce this risk.
Abstract.
Stiles VH, Metcalf BS, Knapp KM, Rowlands AV (2017). A small amount of precisely measured high-intensity habitual physical activity predicts bone health in pre- and post-menopausal women in UK Biobank.
International Journal of Epidemiology,
46(6), 1847-1856.
Abstract:
A small amount of precisely measured high-intensity habitual physical activity predicts bone health in pre- and post-menopausal women in UK Biobank
Background: Physical inactivity is a highly modifiable risk factor for the development of osteoporosis but, due to a lack of research that has precisely and objectively meaured physical activity (PA) relevant to bone, the specific contribution that PA can make to bone health is poorly understood. This study examined whether a more precise measure of PA relelvant to bone was associated with meaures of bone health in pre- and postmenopausal women in UK Biobank. Methods: Time spent at intensities specific to bone health [≥750 milli-gravitational units (mg) and ≥1000 mg] were analysed from raw tri-axial acceleration data averaged over 1-second epochs from 7-day monitoring of habitual PA using accelerometry-based activity monitors (100 Hz; AX3, Axivity, UK) of 1218 pre- and 1316 post-menopausal healthy women. In a cross-sectional analysis, associations between categories of time ( < 1, 1-2 and ≥2minutes) spent above the intensity thresholds and calcaneal quantitative ultrasound measures of bone health (bone mineral density T-score, BMDT-score; speed of sound, SOS; and broadband ultrasound attenuation, BUA) were examined. Results: Compared with < 1minute, spending 1-2 or ≥2minutes/day at intensities ≥1000mg in pre-menopausal and ≥750mg in post-menopausal women was positively associated with BMDT-score, SOS and BUA. Conclusion: Brief bursts of high-intensity PA relevant to bone health can be captured by applying bone-specific thresholds of intensity to raw tri-axial accelerations averaged over 1-second epochs. Accumulating 1-2 minutes/day of high-intensity PA, equivalent to running in pre-menopausal women and slow jogging in post-menopausal women, is associated with better bone health.
Abstract.
Vlachopoulos D, Barker AR, Ubago-Guisado E, Fatouros IG, Knapp KM, Williams CA, Gracia-Marco L (2017). Longitudinal Adaptations of Bone Mass, Geometry, and Metabolism in Adolescent Male Athletes: the PRO-BONE Study.
J Bone Miner Res,
32(11), 2269-2277.
Abstract:
Longitudinal Adaptations of Bone Mass, Geometry, and Metabolism in Adolescent Male Athletes: the PRO-BONE Study.
Adolescence is a crucial period for bone development, and exercise can enhance bone acquisition during this period of life. However, it is not known how the different loading sports practiced can affect bone acquisition in adolescent male athletes. Therefore, the purpose of the present study was to determine the 1-year longitudinal bone acquisition among adolescent males involved in osteogenic (football) and non-osteogenic (swimming and cycling) sports and to compare with active controls. A total of 116 adolescent males aged 12 to 14 years at baseline were followed for 1 year: 37 swimmers, 37 footballers, 28 cyclists, and 14 active controls. Bone mineral content (BMC) was assessed using dual-energy X-ray absorptiometry (DXA); cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), and section modulus (Z) at the femoral neck was assessed using hip structural analysis (HSA); and bone texture of the lumbar spine was assessed using trabecular bone score (TBS). Serum N-terminal propeptide of procollagen type I (PINP), isomer of the Carboxi-terminal telopeptide of type 1 collagen (CTX-I), total serum calcium, and 25 hydroxyvitamin D [25(OH)D] were analyzed. Footballers had significantly higher adjusted BMC at the lumbar spine (7.0%) and femoral neck (5.0%) compared with cyclists, and significantly greater BMC at the lumbar spine (6.9%) compared with swimmers. Footballers presented significantly greater TBS (4.3%) compared with swimmers, and greater CSMI (10.2%), CSA (7.1%), Z (8.9%) and TBS (4.2%) compared with cyclists. No differences were noted between cyclists and swimmers, both groups had similar bone acquisition compared with controls. PINP was significantly higher in footballers and controls compared with cyclists and swimmers (3.3% to 6.0%), and 25(OH)D was significantly higher in footballers and cyclists compared with swimmers and controls (9.9% to 13.1%). These findings suggest that bone acquisition is higher in adolescent male footballers compared with swimmers and cyclists at the femoral neck and lumbar spine sites of the skeleton. © 2017 American Society for Bone and Mineral Research.
Abstract.
Author URL.
Al Arif SMMR, Asad M, Gundry M, Knapp K, Slabaugh G (2017). Patch-based corner detection for cervical vertebrae in X-ray images.
Signal Processing: Image Communication,
59, 27-36.
Abstract:
Patch-based corner detection for cervical vertebrae in X-ray images
Corners hold vital information about size, shape and morphology of a vertebra in an x-ray image, and recent literature (Al-Arif et al. 2015) [1,2] has shown promising performance for detecting vertebral corners using a Hough forest-based architecture. To provide spatial context, this method generates a set of 12 patches around a vertebra and uses a machine learning approach to predict corners of a vertebral body through a voting process. In this paper, we extend this framework in terms of patch generation and prediction methods. During patch generation, the square region of interest has been replaced with data-driven rectangular and trapezoidal region of interest which better aligns the patches to the vertebral body geometry, resulting in more discriminative feature vectors. The corner estimation or the prediction stage has been improved by utilising more efficient voting process using a single kernel density estimation. In addition, advanced and more complex feature vectors are introduced. We also present a thorough evaluation of the framework with different patch generation methods, forest training mechanisms and prediction methods. In order to compare the performance of this framework with a more general method, a novel multi-scale Harris corner detector-based approach is introduced that incorporates a spatial prior through a naive Bayes method. All these methods have been tested on a dataset of 90 X-ray images and achieved an average corner localization error of 2.01 mm, representing a 33% improvement in localization accuracy compared to the previous state-of-the-art method (Al-Arif et al. 2015) [2].1
Abstract.
McNulty JP, Knapp KM, Brown P (2017). Radiography education in the spotlight. Radiography, 23, S1-S2.
Vlachopoulos D, Barker, Williams CA, Arngrímsson SA, Knapp KM, Metcalf B, Fatouros IG, Moreno LA, Gracia Marco (2017). The impact of sport participation on bone mass and geometry in adolescent males. Medicine and Science in Sports and Exercise
Hopkins SJ, Toms AD, Brown M, Welsman JR, Ukoumunne OC, Knapp KM (2016). A study investigating short- and medium-term effects on function, bone mineral density and lean tissue mass post-total knee replacement in a Caucasian female post-menopausal population: implications for hip fracture risk.
Osteoporos Int,
27(8), 2567-2576.
Abstract:
A study investigating short- and medium-term effects on function, bone mineral density and lean tissue mass post-total knee replacement in a Caucasian female post-menopausal population: implications for hip fracture risk.
UNLABELLED: Significant increased hip fracture incidence has been reported in the year following total knee replacement. This study demonstrates that bone and muscle loss is a post-surgical consequence of total knee replacement, alongside poor outcomes in function and activity potentially contributing to reduced quality of life and increased hip fracture risk. INTRODUCTION: a significant increase in hip fracture incidence in the year following total knee replacement (TKR) surgery has been reported. This study investigated function and activity following TKR and the effects of limited mobility on bone and muscle loss and their potential contribution to hip fracture risk. METHODS: Changes in dual-energy X-ray absorptiometry (DXA) (GE Lunar Prodigy, Bedford MA), bone mineral density (BMD) at the neck of femur (NOF), total hip region (TH) and lumbar spine were measured alongside leg lean tissue mass (LLTM) in post-menopausal Caucasian females following TKR (N = 19) compared to controls (N = 43). Lumbar spine trabecular bone scores (TBSs) were calculated. Ipsilateral/contralateral weight bearing, lower limb function, 3-day pedometer readings, pain levels and falls were also recorded. Measurements were obtained at pre-surgery baseline and at 6 weeks, 6 months and 12 months post-surgery. RESULTS: No statistically significant differences were demonstrated between groups at baseline bilaterally in LLTM or BMD at the NOF and TH. Losses in ipsilateral NOF and TH BMD and contralateral LLTM were significantly higher in the TKR group at 6 months. Impairment in function and weight bearing persisted in the TKR group 12 months post-operatively alongside deficits in bilateral muscle mass and ipsilateral NOF and TH BMD. Falls incidence was not significantly higher in the TKR group. CONCLUSIONS: Bone loss at the hip with associated muscle loss is a consequence of TKR that, in addition to poor patient outcomes in function and activity, potentially contributes to increased hip fracture risk in the year following surgery.
Abstract.
Author URL.
Bleiker J, Knapp KM, Hopkins S, Johnston G (2016). Compassionate care in radiography recruitment, education and training: a post-Francis Report review of the current literature and patient perspectives.
Radiography,
22(3), 257-262.
Abstract:
Compassionate care in radiography recruitment, education and training: a post-Francis Report review of the current literature and patient perspectives
Compassion is elemental in the care of a patient during their medical imaging (MI) procedure and is highly topical in the light of the Francis Report. The patient–practitioner interaction is an amalgam of context, communication and individual differences, and whilst compassion is a term in common parlance in the media, policy and radiographers' professional documents, its meaning and manifestation in radiography recruitment, education and practice are less clearly articulated. A review of the existing literature was undertaken, including a small scale study exploring patients' experiences in diagnostic medical imaging. Themes from the study included communication; competence; emotions; attitudes and relationships, but notably absent was any mention of compassion per se. Radiography research would benefit from further exploratory work into the nature of compassionate patient care in the unique context of the medical imaging encounter; offering an evidence-based contribution to radiography in the light of the Francis Report.
Abstract.
Bowtell JL, Jackman SR, Scott S, Connolly LJ, Mohr M, Ermidis G, Julian R, Yousefian F, Helge EW, Jørgensen NR, et al (2016). Short duration small sided football and to a lesser extent whole body vibration exercise induce acute changes in markers of bone turnover.
BioMed Research International,
2016Abstract:
Short duration small sided football and to a lesser extent whole body vibration exercise induce acute changes in markers of bone turnover
We aimed to study whether short-duration vibration exercise or football sessions of two different durations acutely changed plasma markers of bone turnover and muscle strain. Inactive premenopausal women (n=56) were randomized to complete a single bout of short (FG15) or long duration (FG60) small sided football or low magnitude whole body vibration training (VIB). Procollagen type 1 amino-terminal propeptide (P1NP) was increased during exercise for FG15 (51.6±23.0 to 56.5±22.5 μg·L-1, mean ± SD, P
Abstract.
Meertens RM, Knapp KM, Strain WD, Casanova F (2016). The Effects of Lumbar Sympathectomy on Bone and Soft Tissue Haemodynamics of the Leg recorded using Near Infrared Spectroscopy: a Case Report. Journal of Biomedical Engineering and Informatics, 3, 28-32.
Vlachopoulos D, Barker A, Williams C, Knapp K, Metcalf B, Arngrimsson S, Fatouros I, Gracia-Marco L (2016). UK popular sports and hip differences on bone outcomes in adolescent male athletes: the PRO-BONE study. Bone Abstracts
Meertens RM, Strain WD, Knapp KM (2015). A Review of the Mechanisms, Diagnosis and Preventative Treatment of Osteoporotic Fragility Fractures in Patients with Type 2 Diabetes Mellitus.
Journal of Endocrinology and Metabolism,
Volume 5(Number 1-2), 157-162.
Abstract:
A Review of the Mechanisms, Diagnosis and Preventative Treatment of Osteoporotic Fragility Fractures in Patients with Type 2 Diabetes Mellitus
The primary association of both type 2 diabetes mellitus (T2DM) and fragility fractures with age has become cause for concern in the developed world, with T2DM now considered an independent risk factor for an increased risk of fragility fracture. The increased susceptibility to fragility fracture associated with T2DM has wide ranging and increasing socioeconomic, morbidity and mortality effects. As the incidence of T2DM increases, understanding the mechanisms behind why T2DM is a causative risk factor to decreased bone health is an important step. These may be split into two broad categories: those that involve an increased risk of falling, and those mechanisms that make fragility fracture after falling more likely due to detrimental changes to bone strength. The latter is not definitively understood making diagnosis in T2DM populations difficult. Current diagnostic methods do not sufficiently account for the unique endocrinological effects of T2DM on bone. New markers for identifying fragility fracture risk in patients with T2DM are required to overcome the paradoxical increase in bone mineral density (BMD) in these populations, and the shortcomings of predictive algorithms and dual energy X-ray absorptiometry (DXA) in identifying fracture risk in T2DM populations. Earlier identification of patients with T2DM who are at risk of fragility fracture is important, as these patients are not as responsive to current preventative medical interventions as those without T2DM, although there are also adoptive lifestyle changes that can help.
Abstract.
Knapp K, Meertens R, Ashton LR, Hopkins S (2015). Dual energy x-ray absorptiometry beyond bone mineral density measurement: vertebral fracture assessment. Imaging and Oncology for Imaging and Therapy Professionals, 48-53.
Knapp KM, Welsman JR, Hopkins SJ, Shallcross A, Fogelman I, Blake GM (2015). Obesity increases precision errors in total body dual-energy x-ray absorptiometry measurements.
Journal of Clinical Densitometry,
18(2), 209-216.
Abstract:
Obesity increases precision errors in total body dual-energy x-ray absorptiometry measurements
Total body (TB) dual-energy X-ray absorptiometry (DXA) is increasingly being used to measure body composition in research and clinical settings. This study investigated the effect of body mass index (BMI) and body fat on precision errors for total and regional TB DXA measurements of bone mineral density, fat tissue, and lean tissue using the GE Lunar Prodigy (GE Healthcare, Bedford, UK). One hundred forty-four women with BMI's ranging from 18.5 to 45.9kg/m2 were recruited. Participants had duplicate DXA scans of the TB with repositioning between examinations. Participants were divided into 3 groups based on their BMI, and the root mean square standard deviation and the percentage coefficient of variation were calculated for each group. The root mean square standard deviation (percentage coefficient of variation) for the normal (30kg/m2; n=32) BMI groups, respectively, were total BMD (g/cm2): 0.009 (0.77%), 0.009 (0.69%), 0.011 (0.91%); total fat (g): 545 (2.98%), 486 (1.72%), 677 (1.55%); total lean (g): 551 (1.42%), 540 (1.34%), and 781 (1.68%). These results suggest that serial measurements in obese subjects should be treated with caution because the least significant change may be larger than anticipated.
Abstract.
Birch C, Knapp K, Hopkins S, Gallimore S, Rock B (2015). SpineAnalyzer™ is an accurate and precise method of vertebral fracture detection and classification on dual-energy lateral vertebral assessment scans.
Radiography,
21(3), 278-281.
Abstract:
SpineAnalyzer™ is an accurate and precise method of vertebral fracture detection and classification on dual-energy lateral vertebral assessment scans
Osteoporotic fractures of the spine are associated with significant morbidity, are highly predictive of hip fractures, but frequently do not present clinically. When there is a low to moderate clinical suspicion of vertebral fracture, which would not justify acquisition of a radiograph, vertebral fracture assessment (VFA) using Dual-energy X-ray Absorptiometry (DXA) offers a low-dose opportunity for diagnosis. Different approaches to the classification of vertebral fractures have been documented. The aim of this study was to measure the precision and accuracy of SpineAnalyzer™, a quantitative morphometry software program. Lateral vertebral assessment images of 64 men were analysed using SpineAnalyzer™ and standard GE Lunar software. The images were also analysed by two expert readers using a semi-quantitative approach. Agreement between groups ranged from 95.99% to 98.60%. The intra-rater precision for the application of SpineAnalyzer™ to vertebrae was poor in the upper thoracic regions, but good elsewhere. SpineAnalyzer™ is a reproducible and accurate method for measuring vertebral height and quantifying vertebral fractures from VFA scans.
Abstract.
Rimes SJ, Fox D, Knapp KM, Meertens R (2015). The development and evaluation of an audit tool for measuring reporting accuracy of radiographers compared with radiologists for intra-luminal pathology detected at computed tomography colonography (CTC).
Radiography,
21(3), 264-268.
Abstract:
The development and evaluation of an audit tool for measuring reporting accuracy of radiographers compared with radiologists for intra-luminal pathology detected at computed tomography colonography (CTC)
Objective: to design and test an audit tool to measure the reporting accuracy of radiographers using radiologist reports as the gold standard. Design: a database was designed to capture radiographer and radiologist report data. The radiographer preliminary evaluation of intraluminal pathology was given a score (PDS score) by the reporting radiologist based on the pathology present, the discrepancy between the preliminary evaluation and the final report and the significance of that discrepancy on the clinical management of the patient. To test the reliability of this scoring system, 30 randomly selected cases (n=1815) were retrospectively compared and assessed for accuracy using the PDS score by 3 independent practitioners. Inter rater reliability was assessed using percentage agreement and kappa scores. Results: There was 100% agreement between participants for all significant pathologies. Inter rater agreement was 80-93% for normal studies and insignificant pathologies. Conclusion: Results indicate that the tool provides a practical, easy to use and reliable method to record, monitor and evaluate a preliminary evaluation of the colon by radiographers.
Abstract.
Cantin P, Knapp KM (2014). Diagnostic image quality in gynaecological ultrasound: Who should measure it, what should we measure and how?.
Ultrasound,
22, 44-51.
Abstract:
Diagnostic image quality in gynaecological ultrasound: Who should measure it, what should we measure and how?
Assessment of diagnostic image quality in gynaecological ultrasound is an important aspect of imaging department
quality assurance. This may be addressed through audit, but who should undertake the audit, what should be measured
and how, remains contentious. The aim of this study was to identify whether peer audit is a suitable method of assessing
the diagnostic quality of gynaecological ultrasound images. Nineteen gynaecological ultrasound studies were independently
assessed by six sonographers utilising a pilot version of an audit tool. Outcome measures were levels of inter-rater
agreement using different data collection methods (binary scores, Likert scale, continuous scale), effect of ultrasound
study difficulty on study score and whether systematic differences were present between reviewers of different clinical
grades and length of experience. Inter-rater agreement ranged from moderate to good depending on the data collection
method. A continuous scale gave the highest level of inter-rater agreement with an intra-class correlation coefficient of
0.73. A strong correlation (r¼0.89) between study difficulty and study score was yielded. Length of clinical experience
between reviewers had no effect on the audit scores, but individuals of a higher clinical grade gave significantly lower
scores than those of a lower grade (p¼0.04). Peer audit is a promising tool in the assessment of ultrasound image quality.
Continuous scales seem to be the best method of data collection implying a strong element of heuristically driven decision
making by reviewing ultrasound practitioners.
Abstract.
Connolly LJ, Scott S, Mohr M, Ermidis G, Julian R, Bangsbo J, Jackman SR, Bowtell JL, Davies RC, Hopkins SJ, et al (2014). Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45.
Journal of Sport and Health Science,
3(4), 284-292.
Abstract:
Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45
Purpose: the present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n=13) and oscillating whole-body vibration training vibration group (VG, n=17) on body composition, aerobic fitness, and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO, n=14). Methods: Training for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HRs) of ~155 and 90bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on- and off-kinetics, and HR measurements during standardised submaximal exercise were performed. Results: After 16 weeks of training in SG, fat percentage was lowered (p=0.03) by 1.7%±2.4% from 37.5%±6.9% to 35.8%±6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4%±8%, p=0.04), with no changes in VG or CO (time-group effect: p=0.03 and p=0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (6%±5% of HRmax, p=0.01). Conclusion: Short duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women.
Abstract.
Connolly LJ, Scott S, Mohr M, Ermidis G, Julian R, Bangsbo J, Jackman SR, Bowtell JL, Davies RC, Hopkins SJ, et al (2014). Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45. Journal of Sport and Health Science
Hopkins SJ, Welsman JR, Knapp KM (2014). Short-term Precision Error in Dual Energy X-Ray Absorptiometry, Bone Mineral Density and Trabecular Bone Score Measurements; and Effects of Obesity on Precision Error. Journal of Biomedical Graphics and Computing, 4(2), 8-14.
Rimes SJ, Fox D, Knapp KM, Meertens R (2014). The development and evaluation of an audit tool for measuring reporting accuracy of radiographers compared with radiologists for intra-luminal pathology detected at computed tomography colonography (CTC).
RadiographyAbstract:
The development and evaluation of an audit tool for measuring reporting accuracy of radiographers compared with radiologists for intra-luminal pathology detected at computed tomography colonography (CTC)
Objective: to design and test an audit tool to measure the reporting accuracy of radiographers using radiologist reports as the gold standard. Design: a database was designed to capture radiographer and radiologist report data. The radiographer preliminary evaluation of intraluminal pathology was given a score (PDS score) by the reporting radiologist based on the pathology present, the discrepancy between the preliminary evaluation and the final report and the significance of that discrepancy on the clinical management of the patient. To test the reliability of this scoring system, 30 randomly selected cases (n=1815) were retrospectively compared and assessed for accuracy using the PDS score by 3 independent practitioners. Inter rater reliability was assessed using percentage agreement and kappa scores. Results: There was 100% agreement between participants for all significant pathologies. Inter rater agreement was 80-93% for normal studies and insignificant pathologies. Conclusion: Results indicate that the tool provides a practical, easy to use and reliable method to record, monitor and evaluate a preliminary evaluation of the colon by radiographers.
Abstract.
Hopkins S, Smith C, Toms A, Brown M, Welsman J, Knapp K (2013). Evaluation of a dual-scales method to measure weight-bearing through the legs, and effects of weight-bearing inequalities on hip bone mineral density and leg lean tissue mass.
J Rehabil Med,
45(2), 206-210.
Abstract:
Evaluation of a dual-scales method to measure weight-bearing through the legs, and effects of weight-bearing inequalities on hip bone mineral density and leg lean tissue mass.
OBJECTIVE: to investigate: the accuracy of measuring relative left/right weight-bearing using two identically calibrated weighing scales; the short-term weight-bearing tendencies in a general population of 9 participants and long-term in 42 females; the effect weight-bearing inequalities on hip bone mineral density and leg lean tissue mass. METHOD: Participants were measured standing astride two scales. Short-term volunteers were measured 10 times on one visit, with repositioning between measurements and the long-term group were measured on three visits at 6 month intervals. Baseline bilateral hip and total body Dual X-ray Absorptiometry scans were performed on the long-term group. RESULTS: the short-term Coefficient of Variation is 5.41% and long-term 7.01%. No significant correlations were found between hip bone density differences and weight-bearing inequalities, although a weak correlation of r = 0.31 (p = 0.047) was found for differences in leg lean tissue mass. CONCLUSION: Left/right weight-bearing measured using two scales is a consistent method for evaluating weight distribution through the legs. The short- and long-term weight-bearing tendencies showed a similar degree of variation. Weight-bearing inequalities were not associated with any significant left/right differences in bone mineral density at the hip, but were weakly associated with left-right differences in leg muscle mass.
Abstract.
Author URL.
Knapp KM, Meertens RM, Seymour R (2013). Imaging in Osteoporosis. CME Journal: Geriatric Medicine, 10
Griffin JGL, Knapp KM, Pearce G (2013). Static and mobile DXA scanner in-vivo cross-calibration study.
Radiography,
19(1), 7-10.
Abstract:
Static and mobile DXA scanner in-vivo cross-calibration study
In-vitro cross-calibration of DXA scanning equipment, with a phantom device, has been recommended for assessing agreement between devices co-located within DXA scanning services. This study evaluated in-vivo and in-vitro cross-calibration of a static and a mobile DXA scanner within the same service in their individual clinical settings.50 individuals from a volunteer group were recruited to take part in this study and had DXA measurements made on two GE Lunar Prodigy Advance (GE Lunar, Bedford, UK) scanners. Results in this study showed that the scanners agreed, with no clinically significant differences in BMD measurements made at the same site on the individual devices used in this study. The in-vivo cross-calibration of the instruments was a useful experience, which demonstrated closely calibrated systems and raised the profile of the bone densitometry service within the hospital. © 2012 the College of Radiographers.
Abstract.
Meakin JR, Fulford J, Seymour R, Welsman JR, Knapp KM (2013). The relationship between sagittal curvature and extensor muscle volume in the lumbar spine.
Journal of Anatomy,
222(6), 608-614.
Abstract:
The relationship between sagittal curvature and extensor muscle volume in the lumbar spine
A previous modelling study predicted that the forces applied by the extensor muscles to stabilise the lumbar spine would be greater in spines that have a larger sagittal curvature (lordosis). Because the force-generating capacity of a muscle is related to its size, it was hypothesised that the size of the extensor muscles in a subject would be related to the size of their lumbar lordosis. Magnetic resonance imaging (MRI) data were obtained, together with age, height, body mass and back pain status, from 42 female subjects. The volume of the extensor muscles (multifidus and erector spinae) caudal to the mid-lumbar level was estimated from cross-sectional area measurements in axial T1-weighted MRIs spanning the lumbar spine. Lower lumbar curvature was determined from sagittal T1-weighted images. A stepwise linear regression model was used to determine the best predictors of muscle volume. The mean lower lumbar extensor muscle volume was 281cm3 (SD=49cm3). The mean lower lumbar curvature was 30° (SD=7°). Five subjects reported current back pain and were excluded from the regression analysis. Nearly half the variation in muscle volume was accounted for by the variables age (standardised coefficient, B=-3.2, P=0.03) and lower lumbar curvature (B=0.47, P=0.002). The results support the hypothesis that extensor muscle volume in the lower lumbar spine is related to the magnitude of the sagittal curvature; this has implications for assessing muscle size as an indicator of muscle strength. © 2013 Anatomical Society.
Abstract.
Wood G, Knapp KM, Rock B, Cousens C, Roobottom C, Wilson MR (2013). Visual expertise in detecting and diagnosing skeletal fractures.
Skeletal Radiology,
42(2), 165-172.
Abstract:
Visual expertise in detecting and diagnosing skeletal fractures
Objective: Failure to identify fractures is the most common error in accident and emergency departments. Therefore, the current research aimed to understand more about the processes underlying perceptual expertise when interpreting skeletal radiographs. Materials and methods: Thirty participants, consisting of ten novices, ten intermediates, and ten experts were presented with ten clinical cases of normal and abnormal skeletal radiographs of varying difficulty (obvious or subtle) while wearing eye tracking equipment. Results: Experts were significantly more accurate, more confident, and faster in their diagnoses than intermediates or novices and this performance advantage was more pronounced for the subtle cases. Experts were also faster to fixate the site of the fracture and spent more relative time fixating the fracture than intermediates or novices and this was again most pronounced for subtle cases. Finally, a multiple linear regression analysis found that time to fixate the fracture was inversely related to diagnostic accuracy and explained 34 % of the variance in this variable. Conclusions: the results suggest that the performance advantage of expert radiologists is underpinned by superior pattern recognition skills, as evidenced by a quicker time to first fixate the pathology, and less time spent searching the image. © 2012 ISS.
Abstract.
Wood G, Knapp KM, Rock B, Cousens C, Roobottom C, Wilson MR (2013). Visual expertise in detecting and diagnosing skeletal fractures.
Skeletal Radiol,
42(2), 165-172.
Abstract:
Visual expertise in detecting and diagnosing skeletal fractures.
OBJECTIVE: Failure to identify fractures is the most common error in accident and emergency departments. Therefore, the current research aimed to understand more about the processes underlying perceptual expertise when interpreting skeletal radiographs. MATERIALS AND METHODS: Thirty participants, consisting of ten novices, ten intermediates, and ten experts were presented with ten clinical cases of normal and abnormal skeletal radiographs of varying difficulty (obvious or subtle) while wearing eye tracking equipment. RESULTS: Experts were significantly more accurate, more confident, and faster in their diagnoses than intermediates or novices and this performance advantage was more pronounced for the subtle cases. Experts were also faster to fixate the site of the fracture and spent more relative time fixating the fracture than intermediates or novices and this was again most pronounced for subtle cases. Finally, a multiple linear regression analysis found that time to fixate the fracture was inversely related to diagnostic accuracy and explained 34 % of the variance in this variable. CONCLUSIONS: the results suggest that the performance advantage of expert radiologists is underpinned by superior pattern recognition skills, as evidenced by a quicker time to first fixate the pathology, and less time spent searching the image.
Abstract.
Author URL.
Knapp KM, Welsman JR, Hopkins SJ, Fogelman I, Blake GM (2012). Obesity Increases Precision Errors in Dual-Energy X-Ray Absorptiometry Measurements.
Journal of Clinical Densitometry,
15(3), 315-319.
Abstract:
Obesity Increases Precision Errors in Dual-Energy X-Ray Absorptiometry Measurements
The precision errors of dual-energy X-ray absorptiometry (DXA) measurements are important for monitoring osteoporosis. This study investigated the effect of body mass index (BMI) on precision errors for lumbar spine (LS), femoral neck (NOF), total hip (TH), and total body (TB) bone mineral density using the GE Lunar Prodigy. One hundred two women with BMIs ranging from 18.5 to 45.9kg/m 2 were recruited. Participants had duplicate DXA scans of the LS, left hip, and TB with repositioning between scans. Participants were divided into 3 groups based on their BMI and the percentage coefficient of variation (%CV) calculated for each group. The %CVs for the normal (30kg/m 2) (n=28) BMI groups, respectively, were LS BMD: 0.99%, 1.30%, and 1.68%; NOF BMD: 1.32%, 1.37%, and 2.00%; TH BMD: 0.85%, 0.88%, and 1.06%; TB BMD: 0.66%, 0.73%, and 0.91%. Statistically significant differences in precision error between the normal and obese groups were found for LS (p=0.0006), NOF (p=0.005), and TB BMD (p=0.025). These results suggest that serial measurements in obese subjects should be treated with caution because the least significant change may be larger than anticipated. © 2012 the International Society for Clinical Densitometry.
Abstract.
Knapp KM, Welsman JR, Hopkins SJ, Fogelman I, Blake GM (2012). Obesity increases precision errors in dual-energy X-ray absorptiometry measurements.
J Clin Densitom,
15(3), 315-319.
Abstract:
Obesity increases precision errors in dual-energy X-ray absorptiometry measurements.
The precision errors of dual-energy X-ray absorptiometry (DXA) measurements are important for monitoring osteoporosis. This study investigated the effect of body mass index (BMI) on precision errors for lumbar spine (LS), femoral neck (NOF), total hip (TH), and total body (TB) bone mineral density using the GE Lunar Prodigy. One hundred two women with BMIs ranging from 18.5 to 45.9 kg/m(2) were recruited. Participants had duplicate DXA scans of the LS, left hip, and TB with repositioning between scans. Participants were divided into 3 groups based on their BMI and the percentage coefficient of variation (%CV) calculated for each group. The %CVs for the normal (30 kg/m(2)) (n=28) BMI groups, respectively, were LS BMD: 0.99%, 1.30%, and 1.68%; NOF BMD: 1.32%, 1.37%, and 2.00%; TH BMD: 0.85%, 0.88%, and 1.06%; TB BMD: 0.66%, 0.73%, and 0.91%. Statistically significant differences in precision error between the normal and obese groups were found for LS (p=0.0006), NOF (p=0.005), and TB BMD (p=0.025). These results suggest that serial measurements in obese subjects should be treated with caution because the least significant change may be larger than anticipated.
Abstract.
Author URL.
Allison R, Knapp KM (2012). SPASTICITY MANAGEMENT WITH BOTULINUM TOXIN: DEVELOPMENT AND EVALUATION OF a TOOL FOR AUDIT.
JOURNAL OF REHABILITATION MEDICINE,
44(7), 558-561.
Author URL.
Bleiker J, Knapp KM, Frampton IJ (2011). Teaching patient care to students: a blended learning approach in radiography education. Radiography
Knapp KM, Rowlands AV, Welsman JR, Macleod KM (2010). Prolonged unilateral disuse osteopenia 14 years post external fixator removal: a case history and critical review.
Case Rep Med,
2010Abstract:
Prolonged unilateral disuse osteopenia 14 years post external fixator removal: a case history and critical review.
Disuse osteopenia is a complication of immobilisation, with reversal generally noted upon remobilisation. This case report focuses on a patient who was seen 18 years following a road traffic collision when multiple fractures were sustained. The patient had an external fixator fitted for a tibia and fibula fracture, which remained in situ for a period of 4 years. Following removal, the patient was mobilised but, still required a single crutch to aid walking. Fourteen years post removal of the fixator, the patient had a DXA scan which, demonstrated a T-score 2.5 SD lower on the affected hip. This places the patient at an increased risk of hip fracture on this side, which requires monitoring. There appear to be no current studies investigating prolonged disuse-osteopenia in patients following removal of long-term external fixators. Further research is required to quantify unilateral long-term effects to bone health and fracture risk in this population.
Abstract.
Author URL.
Knapp KM (2009). Quantitative ultrasound and bone health.
Salud Publica Mex,
51 Suppl 1, S18-S24.
Abstract:
Quantitative ultrasound and bone health.
This review of quantitative ultrasound (QUS) and bone health uses the current literature to summarise the clinical and research effectiveness of QUS. QUS has been demonstrated to have the ability to predict fracture, particularly at the hip. However, the magnitude of prediction is fracture-site, measurement-site and device dependent. The correlations between dual X-ray absorptiometry (DXA) and bone mineral density (BMD) are weak to moderate, resulting in different subjects being identified as being at risk of fracture by the two different methods. QUS is sensitive to age and menopause-related changes and to clinical risk factors and lifestyle factors associated with osteoporosis. Whilst a limited ability of QUS to monitor therapeutic intervention has been demonstrated, this is still an area where it's poorer precision, in comparison to DXA, results in limited applicability. Whilst DXA remains the gold standard for the diagnosis of osteoporosis, QUS may be of use for the prediction of those at risk of future fracture in areas where there is limited availability of DXA.
Abstract.
Author URL.
Knapp KM, Green S (2009). Reporting of dual energy x-ray absorptiometry scans by radiographers. Osteoporosis Review, 17(1), 22-25.
Moger CJ, Barrett R, Bleuet P, Bradley DA, Ellis RE, Green EM, Knapp KM, Muthuvelu P, Winlove CP (2007). Regional variations of collagen orientation in normal and diseased articular cartilage and subchondral bone determined using small angle X-ray scattering (SAXS).
Osteoarthritis Cartilage,
15(6), 682-687.
Abstract:
Regional variations of collagen orientation in normal and diseased articular cartilage and subchondral bone determined using small angle X-ray scattering (SAXS).
OBJECTIVE: to determine regional differences in the orientation of collagen in the articular cartilage of the equine metacarpophalangeal joint as well as describing cartilage orientation in lesions using small angle X-ray scattering (SAXS). DESIGN: SAXS diffraction patterns were taken at the European Synchrotron Radiation Facility (ESRF), with increasing depth into cartilage and bone cross sections. Results for healthy samples were taken at different regions along the joint which receive different loads and differences in collagen orientation were determined. Results were also taken from diseased samples and the collagen orientation changes from that of healthy samples observed. RESULTS: Regions subject to low loads show a lower degree of orientation and regions exposed to the highest loads possess oriented collagen fibres especially in the radial layer. In early lesions the orientations of the collagen fibres are disrupted. Subchondral bone fibres are twisted in regions where the joint receives shear forces. Changes in fibre orientation are also observed in the calcified cartilage even in regions where the cartilage is intact. In more advanced lesions where there is loss of cartilage the fibres in the calcified layer are realigned tangential to the surface. CONCLUSIONS: Regional variations in collagen arrangement show that the highly ordered layers of the articular cartilage are the most important elements in supporting high variable loads. In lesions changes occur in the deep tissue whilst the overlying cartilage appeared normal. We therefore suggest that the interface region is a key element in the early stages of the disease.
Abstract.
Author URL.
Mansfield J, Winlove CP, Knapp K, Matcher S (2006). Imaging articular cartilage using non-linear microscopy. Journal of Biomechanics, 39, s452-s453.
Moger CJ, Bleuet P, Barrett R, Ellis RE, Knapp KM, Winlove CP (2006). Mechanical properties of cartilage under load determined using small angle X-ray diffraction (SAXS) and Raman micro-spectrometry. Journal of Biomechanics, 39
Blake GM, Knapp KM, Spector TD, Fogelman I (2006). Predicting the risk of fracture at any site in the skeleton: are all bone mineral density measurement sites equally effective?.
Calcif Tissue Int,
78(1), 9-17.
Abstract:
Predicting the risk of fracture at any site in the skeleton: are all bone mineral density measurement sites equally effective?
The ability to assess a patient's risk of fracture is fundamental to the clinical role of bone densitometry. Fracture discrimination is quantified by the relative risk (RR), defined as the increased risk of fracture for a 1 standard deviation decrease in bone mineral density (BMD). The larger the value of RR, the more effective measurements are at identifying patients at risk of fracture. Epidemiological studies show that RR values for predicting the risk of any fracture are approximately the same for all BMD measurement sites. In this study, we show theoretically that this interesting observation is predictable and a consequence of two related observations: (1) that fracture prediction by BMD measurement sites distant from the fracture site is quantitatively explained by the correlation of BMD measurements and (2) that all correlation coefficients between distant BMD sites are comparable, with values in the range r = 0.55-0.65. The first of these conditions (referred to as the correlation hypothesis) is important because it sets a lower limit on the RR values at distant BMD sites on the assumption that measurements at these sites contain no independent information about fracture risk over and above that provided by their correlation with the fracture site BMD. If the correlation hypothesis is true, the present study points to the importance of the correlation coefficient between BMD sites as a key index that is indicative of the ability of different types of measurement to predict fracture risk. If, on the contrary, the correlation hypothesis is not valid, there is scope to improve bone densitometry by further studies to better identify those measurements that do provide independent information about fracture risk and how best to integrate this information with existing techniques to improve decision making.
Abstract.
Author URL.
Blake GM, Knapp KM, Fogelman I (2005). Dual X-ray absorptiometry: clinical evaluation of a new cone-beam system.
Calcif Tissue Int,
76(2), 113-120.
Abstract:
Dual X-ray absorptiometry: clinical evaluation of a new cone-beam system.
The DMS Lexxos is the first cone-beam dual X-ray absorptiometry (DXA) system capable of performing bone mineral density (BMD) measurements of the spine and hip. By using a two-dimensional (2-D) detector array rather than the linear array used with conventional fan-beam DXA systems, image acquisition time on Lexxos is only 1.5 s. However, the need to correct for the large signal from scattered radiation reaching the detector is a potential source of error in cone-beam DXA. The aim of this clinical evaluation of the Lexxos bone densitometer was to investigate the relative accuracy of cone-beam BMD measurements compared with conventional DXA by performing an in vivo cross-calibration study with an established fan-beam system, the Hologic QDR-4500. Spine (L1-L4) and hip BMD measurements were performed in 135 patients (111 women, 24 men) referred for a bone densitometry examination. Duplicate Lexxos measurements were performed in 27 female patients to evaluate precision. On average, Lexxos spine and femoral neck BMD measurements were 2% lower than those on the QDR-4500, whereas total hip BMD was 5% higher. Larger differences were found for the trochanter and Ward's triangle regions. For all sites, Lexxos BMD measurements showed a strong linear relationship with those measured on the QDR-4500 with correlation coefficients in the range r = 0.95 to 0.97 for the clinically important spine, femoral neck, and total hip regions. The root mean standard error (RMSE) between Lexxos and QDR-4500 BMDs ranged from 0.037 g/cm(2) for the femoral neck to 0.060 g/cm(2) for the spine, whereas Lexxos precision was 1.3% for total hip, 2.0% for femoral neck, and 2.3% for spine BMD. Although for the hip BMD sites the RMSE and precision of Lexxos measurements were similar to studies of pencil-beam and fan-beam DXA systems, the results for the spine were poorer than expected. The findings of this study suggest that Lexxos corrects accurately for the effects of scattered radiation at the detector, but that the precision of spine BMD measurements may be limited by involuntary patient movement between the high and low energy X-ray exposures.
Abstract.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2004). Can the WHO definition of osteoporosis be applied to multi-site axial transmission quantitative ultrasound?.
Osteoporos Int,
15(5), 367-374.
Abstract:
Can the WHO definition of osteoporosis be applied to multi-site axial transmission quantitative ultrasound?
Osteoporosis is a highly prevalent but preventable disease and, as such, it is important that there are appropriate diagnostic criteria to identify those at risk of low trauma fracture. In 1994 the World Health Organization (WHO) introduced definitions of osteoporosis and osteopenia using T-scores, which identified 30% of all Caucasian post-menopausal women as having osteoporosis. However, the use of the WHO T-score thresholds of -2.5 for osteoporosis and -1.0 for osteopenia may be inappropriate at skeletal sites other than the spine, hip and forearm or when other modalities, such as quantitative ultrasound (QUS) are used. The aim of this study was to evaluate the age-dependence of T-scores for speed of sound (SOS) measurements at the radius, tibia, phalanx and metatarsal by use of the Sunlight Omnisense, to evaluate the prevalence of osteoporosis and osteopenia at these sites by use of the WHO criteria, and calculate appropriate equivalent T-score thresholds. The study population consisted of 278 healthy pre-menopausal women, 194 healthy post-menopausal women and 115 women with atraumatic vertebral fractures. All women had SOS measurements at the radius, tibia, phalanx and metatarsal and bone mineral density (BMD) measurements at the lumbar spine and hip. A group of healthy pre-menopausal women aged 20-40 years from the pre-menopausal group were used to estimate the population mean and SD for each of the SOS and BMD measurement sites. Healthy post-menopausal women were classified into normal, osteopenic or osteoporotic, based upon the standard WHO definition of osteoporosis and expressed as a percentage. We investigated the age-related decline in T-scores from 20-79 by stratifying the healthy subjects into 10-year age groups and calculating the mean T-score for each of these groups. Finally, we estimated appropriate T-score thresholds, using five different approaches. The prevalence of osteoporosis in the post-menopausal women aged 50 years and over ranged from 1.4 to 12.7% for SOS and 1.3 to 5.2% for BMD. The age-related decline in T-scores ranged from -0.92 to -1.80 for SOS measurements in the 60 to 69-year age group and -0.60 to -1.19 for BMD measurements in the same age group. The WHO definition was not suitable for use with SOS measurements, and revised T-score thresholds for the diagnosis of osteoporosis of -2.6, -3.0, -3.0 and -2.2 and for osteopenia of -1.4, -1.6, -2.3, and -1.4, for the radius, tibia, phalanx and metatarsal, respectively, were recommended.
Abstract.
Author URL.
Somner J, McLellan S, Cheung J, Mak YT, Frost ML, Knapp KM, Wierzbicki AS, Wheeler M, Fogelman I, Ralston SH, et al (2004). Polymorphisms in the P450 c17 (17-hydroxylase/17,20-Lyase) and P450 c19 (aromatase) genes: association with serum sex steroid concentrations and bone mineral density in postmenopausal women.
J Clin Endocrinol Metab,
89(1), 344-351.
Abstract:
Polymorphisms in the P450 c17 (17-hydroxylase/17,20-Lyase) and P450 c19 (aromatase) genes: association with serum sex steroid concentrations and bone mineral density in postmenopausal women.
The CYP 17 and CYP 19 genes encode 17alpha-hydroxylase/17,20-lyase and aromatase, respectively, both involved in sex hormone synthesis. We investigated the association between 2 common polymorphisms in 1) the promoter region (T-->C substitution) of CYP 17, and 2) exon 3 (G-->A) of CYP 19, bone mineral density (BMD) and serum androgen/estradiol, in a case-control study of 252 postmenopausal women aged 64.5 +/- 9.2 yr (mean +/- SD). There was no significant difference in serum estradiol concentrations between cases (n = 136) and controls (n = 116). The CYP 19 genotype was significantly associated with serum estradiol (P = 0.002). Women with the AA genotype had higher serum estradiol concentrations compared with those with the GG genotype (P = 0.03). In older women, those with the CYP 19 GA and GG genotypes had an increased prevalence of osteoporosis (P = 0.04) and fractures (P = 0.003). We found no significant association between CYP 17 genotype and serum androgens and estradiol concentrations. However, a significant association was seen between BMD values at the femoral neck with CYP 17 genotype in cases (P = 0.04) and in the whole study population (P = 0.012). Subjects with the CC genotype had significantly lower BMD (mean +/- SD: TT, 0.7 +/- 0.16; CC, 0.6 +/- 0.08 g/cm(2); P = 0.006). In conclusion, both CYP 17 and CYP 19 are candidate genes for osteoporosis in postmenopausal women.
Abstract.
Author URL.
Knapp KM, Andrew T, MacGregor AJ, Blake GM, Fogelman I, Spector TD (2003). An investigation of unique and shared gene effects on speed of sound and bone density using axial transmission quantitative ultrasound and DXA in twins.
J Bone Miner Res,
18(8), 1525-1530.
Abstract:
An investigation of unique and shared gene effects on speed of sound and bone density using axial transmission quantitative ultrasound and DXA in twins.
UNLABELLED: the genetic influences of speed of sound (SOS) and BMD were evaluated using 215 pairs of healthy female twins. Genetic influences were found for all SOS and BMD measurements. A combination of shared and unique genetic influences was found to control BMD and SOS at the radius. INTRODUCTION: the aim of this study was to investigate to what extent axial transmission speed of sound (SOS) measurements in cortical bone at multiple, peripheral skeletal sites will be influenced by genetic factors and to estimate the proportion of shared and unique genetic influences controlling bone mineral density (BMD) and SOS at a single site, the radius. MATERIALS AND METHODS: the study population consisted of 215 pairs of healthy female twins. of these, 85 pairs were monozygotic (MZ) and 130 pairs were dizygotic (DZ). The twins had measurements of the nondominant third proximal phalanx, one-third radius, midshaft tibia, and fifth metatarsal using the Sunlight Omnisense and DXA measurements of the lumbar spine, nondominant proximal femur, nondominant radius, and whole body using Hologic QDR-4500W densitometers. Calcaneal quantitative ultrasound (QUS) measurements were performed using the McCue CUBA clinical. Intraclass correlations were calculated, and heritability was estimated using multiple regression analysis. Bivariate analysis of site-matched SOS and BMD measurements at the radius was performed using a variance components analysis program. RESULTS: Age- and body mass index-adjusted heritability estimates ranged from 0.51 (95% CI, 0.32-0.70) to 0.56 (0.37-0.76) for SOS measurements, 0.58 (0.41-0.75) for broadband ultrasound attenuation (BUA), 0.72 (0.58-0.86) to 0.77 (0.63-0.91) for axial BMD, and 0.53 (0.16-0.90) to 0.63 (0.26-1.00) for radius and whole body BMD. The correlation between SOS and DXA at the radius was r = 0.34 (0.29-0.47). Thirty-eight percent (16-57%) of the genetic variance explained by SOS at the radius was also explained by BMD (one-third radius region of interest), with 62% being unique. CONCLUSION: in conclusion, genetic influences were demonstrated for SOS measurements in cortical bone at multiple sites, axial BMD, calcaneal BUA, radius, and whole body BMD. At the radius, up to 38% of the genetic influence is shared by genes controlling BMD and SOS. Clarifying the site specificity and pleiotropic effects of bone genes should help our understanding of these complex pathways.
Abstract.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2003). Differential effects of hormone replacement therapy on bone mineral density and axial transmission ultrasound measurements in cortical bone.
Osteoporos Int,
14(4), 289-294.
Abstract:
Differential effects of hormone replacement therapy on bone mineral density and axial transmission ultrasound measurements in cortical bone.
The menopause has a large effect on bone density, and hormone replacement therapy (HRT) has been shown to be an effective treatment for preventing postmenopausal bone loss. The aim of this study was to compare the effects of HRT use on speed of sound (SOS) measurements at the radius, tibia, phalanx, and metatarsal with bone mineral density (BMD) measurements of the lumbar spine and proximal femur. The study population consisted of 278 healthy premenopausal women, 194 healthy postmenopausal women, and 126 healthy postmenopausal women currently receiving HRT for one or more years. SOS measurements were taken at the radius, tibia, phalanx, and metatarsal using the Sunlight Omnisense, and BMD measurements at the lumbar spine and proximal femur using Hologic QDR-4500 densitometers. Z-scores were calculated using the postmenopausal control group. Z-score differences between the postmenopausal controls and HRT group, for the entire group and with the HRT group subdivided into three groups based on duration of HRT usage, were calculated. Significant postmenopausal bone loss was found for all SOS and BMD measurements. A positive effect of HRT usage was found for all SOS measurement sites and lumbar spine BMD, although only the radius and tibia SOS and lumbar spine BMD reached statistical significance. The Z-score differences between the two groups were 0.44, 0.37, 0.15, and 0.26 for the radius, tibia, phalanx, and metatarsal SOS respectively, and 0.28, 0.00, and -0.03 for the lumbar spine, femoral neck, and total hip BMD respectively. A clear effect of the duration of HRT use was seen for the radius measurements, the differences being less marked elsewhere. In conclusion, these results demonstrate a positive effect of HRT on SOS measurements at the radius and tibia and BMD measurements of the lumbar spine.
Abstract.
Author URL.
Blake GM, Patel R, Knapp KM, Fogelman I (2003). Does the combination of two BMD measurements improve fracture discrimination?.
J Bone Miner Res,
18(11), 1955-1963.
Abstract:
Does the combination of two BMD measurements improve fracture discrimination?
UNLABELLED: Combining information from different types of BMD measurement should improve the evaluation of patients' risk of fracture. This study used a bivariate gaussian model to examine the effect of combining two different BMD measurements. The results show that, in practice, there is little benefit unless the measurements are completely unrelated. INTRODUCTION: Intuitively, the combination of information from two or more different types of bone densitometry investigation should improve our ability to identify patients at high risk of fracture. However, the best way to combine measurements and the resulting gain in fracture discrimination are not known. MATERIALS AND METHODS: in this study, we used a bivariate gaussian model to investigate the effect of combining two different types of bone densitometry measurements. The measurements had individual relative risk values RR1 and RR2 and a correlation coefficient r between their Z-scores. Different approaches to the combination of the two measurements were compared by calculating the area under the curve (AUC) for the receiver operating characteristic (ROC) curve, which was obtained by plotting the percentage of fracture patients against the percentage of the whole population with a Z-score below some chosen threshold. ROC curves were calculated for three cases: (1) one type of measurement only; (2) two different types of measurements combined using their mean Z-score weighted according to the theoretical optimum weighting factors predicted by the bivariate gaussian model; and (3) two different types of measurements combined using the conventional World Health Organization (WHO) approach, where one or other measurement is below a set threshold. The theoretical model was tested using measurements of speed of sound (SOS) in the radius, phalanx, and metatarsal in patients with vertebral and Colles' fractures. RESULTS: Results were calculated for RR values of 1.5, 2.0, and 2.5 and r = 0, 0.5, and 0.7. Although a significant improvement in fracture discrimination was obtained when r = 0 and RR1 = RR2, the improvements obtained when r > or = 0.5 or RR1 double dagger RR2 were relatively modest. Slightly better fracture discrimination was obtained using the weighted mean Z-score approach compared with the WHO approach, although the differences were small. The results of the in vivo study in Colles' and vertebral fracture patients showed close agreement with the predictions of the bivariate gaussian model. CONCLUSION: in practice, from a theoretical point of view, there is unlikely to be any benefit from combining information from different types of bone densitometry measurements unless they are completely unrelated.
Abstract.
Author URL.
Blake GM, Knapp KM, Fogelman I (2002). Absolute fracture risk varies with bone densitometry technique used. A theoretical and in vivo study of fracture cases.
J Clin Densitom,
5(2), 109-116.
Abstract:
Absolute fracture risk varies with bone densitometry technique used. A theoretical and in vivo study of fracture cases.
The lack of consensus of how the results of peripheral bone mineral density (BMD) measurements should be interpreted is proving a barrier to the wider use of these devices. One approach is to interpret peripheral measurements using thresholds (so-called equivalent T-scores) defined to have the same absolute fracture risk as a femoral neck T-score of -2.5. For this concept to be valid, the estimates of fracture risk for a population should be the same irrespective of the measurement technique used. We tested this prediction both theoretically and in vivo using data for 63 postmenopausal women with Colles fracture and 191 control subjects. The theoretical analysis showed that if the normal population has a Gaussian BMD distribution and fracture risk varies exponentially with Z-score as exp(-beta Z) then patients who experience a low-trauma fracture have a fracture risk that is larger by a factor exp(beta(2)) compared with the fracture risk of the whole population. Using data from the in vivo study, fracture risk predictions were compared for seven different types of measurement (lumbar spine; femoral neck; total hip BMD; and speed of sound [SOS] at the radius, tibia, phalanx, and metatarsal). When quantitative estimates of fracture risk were made for individual subjects, the average risk of fracture for the Colles group varied between 1.03 times larger (for tibial SOS) and 2.77 times larger (for total hip BMD) than the average fracture risk for the whole population. As predicted by the theoretical study, fracture risk varied according to the odds ratio determined by logistic regression analysis. Therefore, estimates of fracture risk derived for the same group of patients varied almost threefold according to the type of measurement. It was concluded that equating estimates of absolute fracture risk for different types of scan should not be used as the basis of deriving equivalent T-scores for interpreting peripheral measurements.
Abstract.
Author URL.
Knapp KM, Blake GM, Fogelman I, Doyle DV, Spector TD (2002). Multisite quantitative ultrasound: Colles' fracture discrimination in postmenopausal women.
Osteoporos Int,
13(6), 474-479.
Abstract:
Multisite quantitative ultrasound: Colles' fracture discrimination in postmenopausal women.
Distal forearm fractures are the most common perimenopausal fracture and are generally associated with osteoporosis. The aim of this study was to evaluate the capability of speed of sound (SOS) measurements in cortical bone at the phalanx, radius, tibia and metatarsal to discriminate Colles' fracture cases from controls in postmenopausal women and to compare this with bone mineral density (BMD) measurements obtained by dual-energy X-ray absorptiometry (DXA). Sixty-three postmenopausal Colles' fracture cases and 191 postmenopausal controls had SOS measurements of the radius, tibia, phalanx and metatarsal using a semi-reflection ultrasound technique and BMD measurements of the lumbar spine and proximal femur using DXA. The age-adjusted odds ratios (ORs) for fracture for the SOS measurement sites were 1.50 [95% CI 1.07-2.10] for the radius, 1.23 [0.86-1.76] for the tibia, 1.85 [1.06-3.23] for the phalanx and 1.74 [1.12-2.71] for the metatarsal site. For the BMD measurements the ORs were 1.95 [1.34-2.85] for the lumbar spine, 2.21 [1.43-3.40] for the femoral neck and 2.62 [1.69-4.08] for the total hip. The benefits of combining sites either by taking their average Z-score or by using the manufacturer's ORI algorithm were evaluated. The two methods yielded similar results and the ORs for the combination of the radius and phalanx were 2.00 [1.21-3.33], for the radius and metatarsal 1.67 [1.05-2.67], for the phalanx and metatarsal 1.86 [1.11-3.08] and for the radius, phalanx and metatarsal 1.81 [1.07-3.06]. Combinations of DXA sites gave 2.22 [1.44-3.41] for the lumbar spine and femoral neck and 2.41 [1.57-3.70] for the lumbar spine and total hip. In conclusion, semi-reflection ultrasound measurements at the radius, phalanx or metatarsal demonstrated an ability to discriminate fracture cases from controls in postmenopausal Colles' fracture patients, although the odds ratios were lower than with spine and femur BMD.
Abstract.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2001). Differential effects of multi-site SOS and DXA on cortical bone with HRT.
JOURNAL OF BONE AND MINERAL RESEARCH,
16, S246-S247.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2001). Multisite quantitative ultrasound: precision, age- and menopause-related changes, fracture discrimination, and T-score equivalence with dual-energy X-ray absorptiometry.
Osteoporos Int,
12(6), 456-464.
Abstract:
Multisite quantitative ultrasound: precision, age- and menopause-related changes, fracture discrimination, and T-score equivalence with dual-energy X-ray absorptiometry.
This study evaluated the clinical utility of a new multisite ultrasound device capable of measuring speed of sound (SOS) at the phalanx, radius, tibia and metatarsal. The in vitro and in vivo short- and long-term precision were evaluated, reference data were collected for 409 healthy white women (236 premenopausal and 173 postmenopausal), and age and menopause related changes were calculated using linear regression. Fracture discrimination was evaluated using 109 women with vertebral fractures and the age-adjusted odds ratios calculated for each standard deviation decrease in SOS measurement. Correlations between SOS measurements and spine and femur bone mineral density (BMD) were calculated. T-score equivalence with BMD was also investigated together with the prevalence of osteoporosis as defined by the WHO criteria. The in vivo short-term precision standardized in T-score units ranged from 0.14 to 0.33 and long-term standardized precision was 0.35-0.65. Postmenopausal age-related bone loss expressed as the annual change in T-score ranged from 0.040 to 0.089 for SOS and 0.053 to 0.066 for BMD, whilst menopause-related annual loss ranged from 0.036 to 0.094 for SOS and 0.050 to 0.074 for BMD. Correlations between the different SOS sites ranged from r = 0.24 to 0.55, and between SOS and BMD from r = 0.12 to 0.47. The odds ratio (and 95% confidence intervals) for fracture per 1 SD decrease in SOS were 2.0 (1.22 to 3.23) for the phalanx; 1.5 (1.01 to 2.24) for the metatarsal; 1.4 (1.03 to 1.99) for the radius and 1.2 (0.87 to 1.66) for the tibia. Odds ratios for BMD in the same population ranged from 2.6 to 4.8 (1.70 to 8.29). The prevalence of osteoporosis as defined by T =
Abstract.
Author URL.
Knapp KM, Andrew T, Blake GM, Fogelman I, Spector TD (2000). The heritability of SOS and BMD - a comparative study between multi-site ultrasound and DXA: a twin study.
JOURNAL OF BONE AND MINERAL RESEARCH,
15, S259-S259.
Author URL.
Knapp KM, de Lange ME, Blake GM, Fogelman I, Spector TD (2000). The heritability of bone quality using multisite ultrasound in the peripheral skeleton: a twin study.
OSTEOPOROSIS INTERNATIONAL,
11, S20-S20.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (1999). Ultrasound measurements at the radius predict vertebral fractures in postmenopausal women.
JOURNAL OF BONE AND MINERAL RESEARCH,
14, S256-S256.
Author URL.
Knapp KM, Blake GM, Fogelman I, Spector TD (1999). Ultrasound measurements at the radius predict wrist fractures in postmenopausal women.
JOURNAL OF BONE AND MINERAL RESEARCH,
14(6), 1052-1052.
Author URL.
Conferences
Malik H, Appelboam A, Taylor G, Wood D, Knapp K (In Press). Ultrasound directed reduction of Colles’ type distal radial fractures in ED (UDiReCT): a randomized controlled trial.
Sayed M, Knapp K, Fulford J, Heales C, Saeed A, Rimes S, Moffatt D (2023). Evaluation of dose reduction potential of a scatter correction software for AP lumbar spine X-Ray imaging. UK Imaging and Oncology Congress. 5th - 7th Jun 2023.
Banfield L, Aboelmagd S, Seymour R, Atkins J, Melzer D, Knapp K (2022). Demonstration of degenerative disease as identified on iDXA images: an inter-observer reliability study. European Congress of Radiology (ECR) Overture. 2nd - 6th Mar 2022.
Abstract:
Demonstration of degenerative disease as identified on iDXA images: an inter-observer reliability study
Abstract.
Rodrigues L, Knapp K, Meakin J, Heales C, Alqahtani A, Gill M, Haji Abdullah Z, Vilela-Mansell C, Ding C (2022). Trabecular bone score (TBS) role in fracture risk assessment. European Congress of Radiology. 13th - 17th Jul 2022.
Abstract:
Trabecular bone score (TBS) role in fracture risk assessment.
Abstract.
Sayed M, Knapp K, Fulford J, Heales C, Alqahtani S, Rimes S, Moffatt D (2022). Virtual grid software for scatter correction to improve image quality and reduce radiation dose, assessed using a TOR CDR image quality phantom. UK Imaging & Oncology. 4th - 6th Jul 2022.
Abstract:
Virtual grid software for scatter correction to improve image quality and reduce radiation dose, assessed using a TOR CDR image quality phantom
Abstract.
Sayed M, Knapp K, Fulford J, Heales C, Alqahtani S, Rimes S, Moffatt D, Najaran SA (2022). X-ray scatter correction software for improving image quality and reducing radiation dose in large anatomical regions. European Congress of Radiology. 13th - 17th Jul 2022.
Abstract:
X-ray scatter correction software for improving image quality and reducing radiation dose in large anatomical regions
Abstract.
Sayed M, Knapp K, Fulford J, Heales C, Alqhatani S (2022). X-ray scatter correction software studies for diagnostic X-ray imaging. UK Imaging & Oncology. 4th - 6th Jul 2022.
Abstract:
X-ray scatter correction software studies for diagnostic X-ray imaging
Abstract.
Elliot J, Williams D, Graham-Black P, Whitehead K, James R, Alqahtani S, Knapp K (2020). Dual energy x-ray absorptiometry: the accuracy of measurements with increasing body fat on the GE Lunar prodigy and GE Lunar iDXA: an in-vitro study. United Kingdom Imaging and Oncology. 1st - 31st Jul 2020.
Abstract:
Dual energy x-ray absorptiometry: the accuracy of measurements with increasing body fat on the GE Lunar prodigy and GE Lunar iDXA: an in-vitro study.
Abstract.
Meertens R, Knapp K, Casanova F, Ball S, Strain W (2020). Near infrared spectroscopy for the investigation of vascular haemodynamics in human bone in vivo. Bone Research Society Annual Meeting. 6th - 8th Jul 2020.
Peters-Cheale P, Hoade L, Heales C, Knapp K (2020). Scope and indications of lumbar spine radiography for lower back pain in the South West. UKIO 2020. 29th Jun - 31st Jul 2020.
Abstract:
Scope and indications of lumbar spine radiography for lower back pain in the South West.
Abstract.
Meertens R, Knapp K, Casanova F, Ball S, Fulford J, Merson S, Strain W (2020). Sex-based differences in vascular haemodynamics at the proximal tibia. European Congress of Radiology. 15th - 19th Jul 2020.
Khumalo J, Abdulle M, Almurairi A, Kazimi A, Asiri M, Fulford J, Strain WD, Knapp KM (2020). Short-term intra- and inter-operator precision errors of radiofrequency echographic multispectrometry bone density measurements at the lumbar spine using the Echolight scanner. United Kingdom Imaging and Oncology. 1st - 31st Jul 2020.
Abstract:
Short-term intra- and inter-operator precision errors of radiofrequency echographic multispectrometry bone density measurements at the lumbar spine using the Echolight scanner.
Abstract.
Meertens R, Knapp K, Casanova F, Ball S, Fulford J, Merson S, Strain W (2020). Vascular measurements of the proximal tibia and their associations with bone mineral density. European Congress of Radiology. 15th - 19th Jul 2020.
Gundry M, Knapp K, Hopkins S, Winzenrieth R, Ferchaud L (2019). 3D Shape Modelling Analysis of the Hip using 3D-SHAPER Software - a Comparison Between Contralateral, Ipsilateral, and Baseline Hips for RTKR, TKR, and Control Participants.
Author URL.
Gundry M, Knapp K, Hopkins S, Winzenrieth R, Ferchaud L (2019). 3D Shape Modelling Analysis of the Hip using 3D-SHAPER Software - a Comparison Between Contralateral, Ipsilateral, and Baseline Hips for RTKR, TKR, and Control Participants.
Author URL.
Meertens RM, Knapp KM, Casanova F, Ball SE, Strain WD (2019). Exploring the potential relationships between microvascular haemodynamics and density in bone: a feasibility study utilising near infrared spectroscopy. UKIO 2019. 10th - 12th Jun 2019.
McAnulla S, Knapp K, Ball S (2019). Understanding diagnostic student radiographer attrition in UK. European Congress of Radiology. 27th Feb - 3rd Mar 2019.
Abstract:
Understanding diagnostic student radiographer attrition in UK
Abstract.
McAnulla S, Knapp K, Ball S (2018). Achieving Excellence in Radiography Education and Research. Achieving Excellence in Radiography Education and Research. 29th Nov - 1st Dec 2018.
Abstract:
Achieving Excellence in Radiography Education and Research
Abstract.
Fuller N, Knapp K, Stokes O, Brown M (2018). CERVICAL SPINE FRACTURES IN THE ELDERLY: ARE THERE MISSED OPPORTUNITIES FOR PREVENTION?.
Author URL.
Gundry M, Hourigan P, Hopkins S, Waterson B, Knapp K, Toms A (2018). COMPARISON OF POST-OPERATION AND PRE-REVISION PATIENTS & RSQUO; BONE MINERAL DENSITY IN TOTAL KNEE REPLACEMENTS COMPARED TO THEIR CONTRALATERAL KNEES.
Author URL.
Fuller N, Stokes O, Brown M, Knapp K (2018). Cervical spine fractures in the elderly: how can radiology aid in their prevention?. UKRO. 2nd - 4th Jul 2018.
Abstract:
Cervical spine fractures in the elderly: how can radiology aid in their prevention?
Abstract.
Alqahtani S, Knapp K, Palfrey R, Meakin J (2018). Construction of obese phantoms for dose optimisation and image quality purposes. European Congress of Radiology. 28th Feb - 4th Mar 2018.
Alqahtani S, Knapp K, Palfrey R, Meakin J (2018). Fabrication of fat tissue-equivalent substitutes (FTES) and lean tissue-equivalent substitute. European Congress of Radiology. 28th Feb - 4th Mar 2018.
Alqahtani A, Meakin J, Knapp K, Fulford J (2018). MRI of the lumbar spine: paraspinal muscle asymmetry in a healthy volunteer population. UKRO. 2nd - 4th Jul 2018.
MacMillan J, Hoade L, Reyes-Aldasoro CC, Knapp KM, Slabaugh G, Appelboam A (2018). Prediction of manipulation under anaesthesia success using local binary pattern features. UKRO. 2nd - 4th Jul 2018.
Abstract:
Prediction of manipulation under anaesthesia success using local binary pattern features.
Abstract.
Al Arif SMMR, Knapp K, Slabaugh G (2018). SPNet: Shape prediction using a fully convolutional neural network.
Abstract:
SPNet: Shape prediction using a fully convolutional neural network
Abstract.
Al Arif SMMR, Knapp K, Slabaugh G (2018). Shape-aware deep convolutional neural network for vertebrae segmentation.
Abstract:
Shape-aware deep convolutional neural network for vertebrae segmentation
Abstract.
Gundry M, Meertens RM, Meakin JR, Knapp KM (2017). Computer-aided detection in musculoskeletal plain radiography: a systematic review.
Abstract:
Computer-aided detection in musculoskeletal plain radiography: a systematic review.
Abstract.
Elder H, Hancock E, Martin S, Spreadbury J, Morris C, Knapp KM (2017). Intra- and inter-operator precision measurements of hip migration using projection radiography and dual energy x-ray absorptiometry.
Abstract:
Intra- and inter-operator precision measurements of hip migration using projection radiography and dual energy x-ray absorptiometry
Abstract.
Knapp KM, Alqahtani SJM, Welbourn R, Meakin JR, Palfrey RM, Thomson K, Rimes SJ (2017). Obese patients in projection radiography: double the weight, quadruple the dose.
Abstract:
Obese patients in projection radiography: double the weight, quadruple the dose.
Abstract.
Masudur Rahman Al Arif SM, Knapp K, Slabaugh G (2017). Probabilistic spatial regression using a deep fully convolutional neural network.
Abstract:
Probabilistic spatial regression using a deep fully convolutional neural network
Abstract.
Masudur Rahman Al Arif SM, Knapp K, Slabaugh G (2017). Probabilistic spatial regression using a deep fully convolutional neural network.
Abstract:
Probabilistic spatial regression using a deep fully convolutional neural network
Abstract.
Knapp KM (2017). Radiography Education.
Abstract:
Radiography Education.
Abstract.
Al Arif SMMR, Knapp K, Slabaugh G (2017). Region-aware deep localization framework for cervical vertebrae in X-ray images.
Abstract:
Region-aware deep localization framework for cervical vertebrae in X-ray images
Abstract.
Ashton L, Fulford J, McAnulla S, Knapp KM, Heales C, Silver D, Williams CA (2017). The incidence of bone marrow oedema in asymptomatic adolescent footballers - an observational study.
Abstract:
The incidence of bone marrow oedema in asymptomatic adolescent footballers - an observational study
Abstract.
Meertens RM, Casanova F, Strain WD, Knapp K, Thorn C (2017). The use of near-infrared systems for investigations of microvascular haemodynamics in human in vivo bone tissue: a systematic review. International Society of Oxygen Transfer to Tissue Annual Meeting 2017. 19th - 23rd Aug 2017.
Knapp K (2016). ADVANCING ALLIED HEALTH PROFESSIONALS' PRACTICE IN OSTEOPOROSIS.
Author URL.
Ashton L, Rooke F, Reeve J, Eade C, Knapp KM (2016). Analysis of training needs for radiographer image interpretation in clinical practice.
Abstract:
Analysis of training needs for radiographer image interpretation in clinical practice
Abstract.
Alqahtani S, Palfrey RM, Meakin JR, Fulford J, Hopkins SJ, Knapp KM (2016). Body composition changes in obese populations.
Abstract:
Body composition changes in obese populations.
Abstract.
Gundry M, Slabaugh G, Appelboam A, Reubens A, Arif MRA, Phillips M, Knapp KM (2016). Can CSPINE-CAD software increase diagnostic accuracy and confidence in c-spine imaging?.
Abstract:
Can CSPINE-CAD software increase diagnostic accuracy and confidence in c-spine imaging?
Abstract.
Knapp KM, Rachuba S, Ashton L, Rooke F, Reeve J, Pitt M (2016). Changing pathways through the minor injuries: Using modelling to support service delivery change.
Abstract:
Changing pathways through the minor injuries: Using modelling to support service delivery change
Abstract.
Malamateniou C, Mellor F, Appleyard R, Knapp KM (2016). FoRRM: a Formal radiography research mentoring scheme to increase research capacity.
Abstract:
FoRRM: a Formal radiography research mentoring scheme to increase research capacity
Abstract.
Al Arif SMMR, Gundry M, Knapp K, Slabaugh G (2016). Global localization and orientation of the cervical spine in X-ray images.
Abstract:
Global localization and orientation of the cervical spine in X-ray images
Abstract.
Al Arif SMMR, Gundry M, Knapp K, Slabaugh G (2016). Improving an active shape model with random classification forest for segmentation of cervical vertebrae.
Abstract:
Improving an active shape model with random classification forest for segmentation of cervical vertebrae
Abstract.
Alqahtani S, Fulford J, Meakin J, Palfrey RM, Knapp KM (2016). Magnetic resonance imaging quantification of visceral and subcutaneous fat mass and its relationship to anthropometric measurements routinely used to quantify health risks.
Abstract:
Magnetic resonance imaging quantification of visceral and subcutaneous fat mass and its relationship to anthropometric measurements routinely used to quantify health risks.
Abstract.
Meertens R, Knapp K, Strain D, Casanova F (2016). NEAR INFRARED SPECTROSCOPY: a POTENTIAL TOOL FOR ASSESSING HAEMODYNAMIC MARKERS OF THE MICROVASCULAR BLOOD SUPPLY WITHIN BONE TISSUE.
Author URL.
Scott S, Knapp K, Broderick A, Fulford J, Krustrup P, Bowtell J (2016). SERUM VITAMIN D STATUS IN ELITE MALE AND FEMALE DANCERS: a 12 WEEK OBSERVATIONAL STUDY.
Author URL.
Meertens RM, Knapp KM, Strain WD, Casanova F (2016). The use of near infrared spectroscopy (NIRS) as a diagnostic tool to measure microvascular haemodynamics in bone tissue. National Osteoporosis Society 2016. 7th - 9th Nov 2016.
Meertens RM, Al-Rubeyi S, Farah W, Furmully M, Knapp K, Green D (2016). Vitamin D deficiency and insufficiency in the radiography population: Are we at risk?. UKRC 2016.
Al-Rubeyi S, Farah W, Furmully M, Meertens R, Shepherd J, Green D, Strain WD, Knapp KM (2016). Vitamin D deficiency and insufficiency in the radiography population: Are we at risk?.
Abstract:
Vitamin D deficiency and insufficiency in the radiography population: Are we at risk?
Abstract.
Knapp KM, Gundry M, Phillips M, Ashton L, Meakin J, Appelboam A, Reuben A, Slabaugh G (2015). Can the Genant semi-quantitative scale for vertebral fracture assessment be applied to cervical spine radiographs using CSPINE-CAD?.
Abstract:
Can the Genant semi-quantitative scale for vertebral fracture assessment be applied to cervical spine radiographs using CSPINE-CAD?
Abstract.
Al Arif SMMR, Asad M, Knapp K, Gundry M, Slabaugh G (2015). Cervical vertebral corner detection using haar-like features and modified hough forest.
Abstract:
Cervical vertebral corner detection using haar-like features and modified hough forest
Abstract.
Jebri B, Phillips M, Knapp K, Appelboam A, Reuben A, Slabaugh G (2015). Detection of Degenerative Change in Lateral Projection Cervical Spine X-ray Images.
Author URL.
Narang B, Phillips M, Knapp K, Appelboam A, Reuben A, Slabaugh G (2015). Semi-Automatic Delineation of the Spino-Laminar Junction Curve on Lateral X-ray Radiographs of the Cervical Spine.
Author URL.
Hopkins SJ, Brown M, Toms AD, Welsman JR, Knapp KM (2014). EFFECTS OF LEG FRACTURES ON BONE MINERAL DENSITY AT THE HIP IN a FEMALE POSTMENOPAUSAL POPULATION: IMPLICATIONS FOR FRACTURE LAISON SERVICES.
Author URL.
Whitlock O, Ferrington-Bolshaw H, Ellis L, Petter L, Knapp KM (2014). HIGH-HEEL WEARING AND CALCANEAL BONE QUALITY IN PREMENOPAUSAL WOMEN: AN INVERSE RELATIONSHIP.
Author URL.
Scott SE, Knapp K, Bowtell J (2014). MOVEMENT TRAINING FOR BONE HEALTH: THE DANCE GRID FEASIBILITY STUDY.
Author URL.
Hopkins SJ, Knapp K, Parker D, Yusof R (2013). Effect of bone area on bone-mineral-density and trabecular-bone-score measurements at the lumbar spine.
Hopkins S, knapp K, Parker D, Yusof R (2013). Short-term precision error in Dual Energy X-Ray Absorptiometry Bone-Mineral-Density and Trabecular-Bone-Score measurements; and effects of obesity.
Hopkins S, Smith C, Toms A, Brown M, Welsman J, Knapp K (2012). A STUDY INVESTIGATING THE LONG-TERM EFFECTS ON FUNCTION, BONE MINERAL DENSITY AND LEAN TISSUE MASS POST TOTAL KNEE REPLACEMENT IN a FEMALE POSTMENOPAUSAL POPULATION.
Author URL.
Knapp K, Scaife L, Paisey R, Warren R, Donohoe M (2012). CHARCOT NEUROARTHROPATHY IS ASSOCIATED WITH LOW BONE MINERAL DENSITY.
Author URL.
Hopkins SJ, Smith C, Toms A, Brown M, Welsman J, Knapp K (2012). Left-right weight-bearing:short and long-term measurement precision, and effects of weight-bearing imbalance on hip bone mineral density and leg lean tissue mass.
Hopkins S, Smith C, Toms A, Brown M, Appelboam A, Welsman J, Knapp K (2012). RELATIONSHIP BETWEEN SPINE BONE MINERAL DENSITY AND TRABECULAR BONE SCORE IN POSTMENOPAUSAL POPULATIONS FOLLOWING TOTAL KNEE REPLACEMENT OR LEG FRACTURE.
Author URL.
Scott E, West H, Kilsby H, Reid EJ, Seymour R, Knapp KM (2011). Do the WHO recommendations for exercise lead to reduced body fatness?. UK Radiological Congress. 6th - 8th Jun 2011.
Reid EJ, Kilsby H, West H, Scott E, Seymour R, Knapp KM (2011). Is body mass index a good measure of body fatness?. UK Radiological Congress. 6th - 8th Jun 2011.
Knapp KM, Green L, Pickett N, Rendell L, Summers IR, Heales CJ (2009). An investigation of the inter-operator precision associated with two different methods of ultrasound quality assurance. 8th - 10th Jun 2009.
Abstract:
An investigation of the inter-operator precision associated with two different methods of ultrasound quality assurance
Abstract.
Green L, Pickett N, Rendell L, Knapp K, Summers I, Heales C (2009). An investigation of the inter-operator precision associated with two different methods of ultrasound quality assurance. UK Radiological Congress. 8th - 10th Jun 2009.
Green L, Pickett N, Rendell L, Knapp K, Summers I, Heales C (2009). An investigation of the sensitivity of two ultrasound quality assurance systems to changes in probe performance. UK Radiological Congress. 8th Oct - 10th Jun 2009.
Knapp KM, Green L, Pickett N, Rendell L, Summers IR, Heales CJ (2009). An investigation of the sensitivity of two ultrasound quality assurance systems to changes in probe performance.
Abstract:
An investigation of the sensitivity of two ultrasound quality assurance systems to changes in probe performance
Abstract.
Willis S, Heales CJ, Knapp K (2009). Can the Use of Virtual Learning Environments (VLEs) promote students’ preparedness to practice?. Meeting the Challenge of Education and Research Today; a Conference for Health and Social Care Academics. 7th - 7th Apr 2009.
Abstract:
Can the Use of Virtual Learning Environments (VLEs) promote students’ preparedness to practice?
Abstract.
Willis S, Heales C, Cousens C, Iyengar S, Knapp K (2009). Is the teaching of skeletal image interpretation at undergraduate level effective in preparing students for practice?. UK Radiological Congress. 8th - 10th Jun 2009.
Abstract:
Is the teaching of skeletal image interpretation at undergraduate level effective in preparing students for practice?
Abstract.
Knapp KM, Willis SJ, Heales CJ, Cousens C, Iyengar S (2009). Is the teaching of skeletal image-interpretation at undergraduate level effective in preparing students for practice?.
Abstract:
Is the teaching of skeletal image-interpretation at undergraduate level effective in preparing students for practice?
Abstract.
Welsman J, Knapp K, MacLeod K, Blake G (2009). OBESITY INCREASES PRECISION ERRORS IN DUAL ENERGY X-RAY ABSORPTIOMETRY MEASUREMENTS.
Author URL.
Heales C, Knapp K, Frost M, Patel R, Moore AEB, Spector T, Fogelman I (2008). Vertebral Fracture Assessment (Using DXA) is a Precise Method of Measuring Intervertebral Disc Height. 2nd Joint Meeting of the Bone Research Society and British Orthopaedic Research Society. 23rd - 25th Jun 2008.
Mansfield J, Winlove CP, Moger J, Knapp K, Matcher S (2007). Second-harmonic and two-photon imaging and polarimetry of articular cartilage.
Abstract:
Second-harmonic and two-photon imaging and polarimetry of articular cartilage
Abstract.
Heales CJ, Knapp KM, Moore AEB, Blake GM, Swaminathan R, Fogelman I (2006). Current pain and the visual analogue scale as a predictor of quality of life in individuals with osteoporosis.
Author URL.
Mansfield JC, Winlove CP, Knapp K, Matcher SJ (2006). Imaging articular cartilage using second harmonic generation microscopy.
Abstract:
Imaging articular cartilage using second harmonic generation microscopy
Abstract.
Moore AEB, Knapp KM, Frost ML, Blake GM, Spector TD, Fogelman I (2006). Is IVA a reliable method of detecting vertebral fractures?.
Author URL.
Heales C, Knappi KM, Moore AEB, Frost ML, Patel R, Blake GM (2006). Quality of life and current pain levels are associated with fracture rather than with osteoporosis.
Author URL.
Mansfield JC, Ugryumova N, Knapp KM, Matcher SJ (2006). The collagen structure of equine articular cartilage, characterized using polarization-sensitive optical coherence tomography and non-linear microscopy.
Abstract:
The collagen structure of equine articular cartilage, characterized using polarization-sensitive optical coherence tomography and non-linear microscopy
Abstract.
Knapp KM, Moore AEB, Frost ML, Blake GM, Spector TD, Fogelman I (2006). Visibility of thoracic vertebra using instant vertebral assessment is dependent on hip bone mineral density.
Author URL.
Blake GM, Knapp KM, Fogelman I (2004). Clinical evaluation of a new cone-beam DXA system.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2004). Is axial transmission ultrasound sensitive to risk factors for osteoporosis?.
Author URL.
Blake GM, Knapp KM, Spector TD, Fogelman I (2004). Predicting the risk of fracture at any site in the skeleton: Are all BMD measurements equally effective?.
Author URL.
Knapp KM, Blake GM, Spector TD, Fogelman I (2003). (Young Investigator Award) - Does combining sites improve fracture discrimination?.
Author URL.
Knapp KM, Koa-Sales RM, Boudousq V, Ruiz I, Kotzki O, Chappard D, Audran M (2003). In-vivo bone mineral measurement of the hip using the lexxos cone beam densitometer: Precision and cross-calibration with hologic densitometers.
Author URL.
Somner J, Mclellan S, Cheung J, Mak YT, Frost ML, Knapp KM, Wierebicki AS, Wheeler M, Fogelman I, Ralston SH, et al (2003). Polymorphisms in the P450C17 (17-hydroxylase/17,20-lyase)and P450C19 (aromatase) genes: Assosiation with serum sex steroids concentrations and bone mineral density in postmenopausal women.
Author URL.
Hampson G, Sankaralingam S, Frost M, Knapp K, Farmer CKT, Fogelman I (2003). Serum osteoprotegerin (OPG) is altered in disorders of bone remodelling including osteoporosis and following nutritional improvement.
Author URL.
Somner J, Cheung J, Mak YT, Prowse E, Frost M, Knapp K, Fogelman I, Wierzbicki AS, Hampson G (2002). Aromatase gene polymorphisms: Association with bone mineral density and serum estradiol concentrations in post-menopausal women.
Author URL.
Knapp KM, Blake GM, Yaniv L, Spector TD, Fogelman I (2002). Can the WHO criteria be applied to multi-site axial transmission quantitative ultrasound?.
Author URL.
Sankaralingam S, Cheung J, Prowse E, Frost M, Knapp K, Fogelman I, Hampson G (2002). Serum osteoprotegerin (OPG): Relationship with age and dietary improvement.
Author URL.