The impact of X-ray scatter correction software on abdomen radiography in terms of image quality and radiation dose.

INTRODUCTION: The conventional anti-scatter grid is widely used in X-ray radiography to reduce scattered X-rays, but it increases patient dose. Scatter-correction software offers a dose-reducing alternative by correcting for scattered X-rays without a physical grid. Grids and software correction are necessary to reduce scatter radiation and improve image quality especially for the large body parts. The scatter correction can be beneficial in situations where the use of grid is challenging. The implementation of grids and advanced software correction techniques is imperative to ensure that radiographic images maintain high levels of clarity, contrast, and resolution, and ultimately facilitating more accurate diagnoses. This study compares image quality and radiation dose for abdomen exams using scatter correction software and physical grids. METHODS: An anthropomorphic phantom (abdomen) underwent imaging with varying fat and lean tissue layers and body mass index (BMI) configurations. Imaging parameters included 70 kVp tube voltage, 110 cm SID, and Automatic Exposure Control (AEC) both lateral and central chambers. AP abdomen X-ray projections were acquired with and without an anti-scatter grid, and scatter correction software was applied. Image quality was assessed using contrast to noise ratio (CNR) and signal to noise ratio (SNR) metrics. The tube current mAs was considered an exposure factor that affected radiation dose and was used to compare the VG software and physical grid. Radiation dose was measured using Dose Area Products (DAP). The effective dose was estimated using Monte Carlo simulation-PCXMC software. Paired t-tests were used to investigate the image quality difference between the Gridless and VG software, Gridless and PG, and VG software and PG approaches. For the DAP and effective dose, paired t-test was used to investigate the difference between VG software and PG. RESULTS: Images acquired with a grid had the highest mean CNR (71.3 ± 32) compared to Gridless (50 ± 33.8) and scatter correction software (59.3 ± 37.9). The mean SNR of the grid images was (82.7.3 ± 38.9), which is 18% higher than the scatter correction software images (70.4 ± 36.7) and 29% higher than in the Gridless images (62.9.3 ± 34). The mean DAP value was reduced by 81% when the scatter correction software was used compared to the grid (mean: 65.4 µGy.m2 and 338.2 µGy.m2, respectively) with a significant difference (p = 0.001). Scatter correction software resulted in a lower effective dose compared to physical grid use, (mean difference± SD = -0.3 ± 0.18 mSv) with a significant difference (P = 0.02). CONCLUSION: Scatter correction software reduced the radiation dose required but images employing a grid yielded higher CNR and SNR. However, the radiation dose reduction might affect the image quality to a level that impacts the diagnostic information available. Thus, further research needs to be conducted to optimise the use of the scatter correction software. IMPLICATION FOR PRACTICE: Objectively, X-ray scatter correction software might be promising in conditions where a grid cannot be applied.

Evaluating the impact of COVID-19 on DXA waiting lists and osteoporosis prescription trends in England 2019-2023.

This study uses NHS waiting times and osteoporosis medication community prescription datasets to assess the impact of COVID-19 on DXA waits and osteoporosis medication patterns in England. Results show significant increases in DXA waiting list times and variation in prescription rates. Investment is needed to improve waiting list times. PURPOSE: This study investigates the impact of COVID-19 on DXA scan waiting lists, service recovery and osteoporosis medication prescriptions in the NHS following the March 2020 national lockdowns and staff redeployment. METHODS: Data from March 2019 to June 2023, including NHS digital diagnostics waiting times (DM01) and osteoporosis medication prescriptions from the English Prescribing Dataset (EPD), were analysed. This encompassed total waiting list data across England's seven regions and prescribing patterns for various osteoporosis medications. Analyses included total activity figures and regression analysis to estimate expected activity without COVID-19, using R for all data analysis. RESULTS: In England, DXA waiting lists have grown significantly, with the yearly mean waiting list length increasing from 31,851 in 2019 to 65,757 in 2023. The percentage of patients waiting over 6 weeks for DXA scans rose from 0.9% in 2019 to 40% in 2020, and those waiting over 13 weeks increased from 0.1% in 2019 to 16.7% in 2020. Prescription trends varied, with increases in denosumab, ibandronic acid and risedronate sodium and decreases in alendronic acid, raloxifene hydrochloride and teriparatide. A notable overall prescription decrease occurred in the second quarter of 2020. CONCLUSION: COVID-19 has significantly increased DXA scan waiting lists with ongoing recovery challenges. There is a noticeable disparity in DXA service access across England. Osteoporosis care, indicated by medication prescriptions, also declined during the pandemic. Addressing these issues requires focused investment and effort to improve DXA scan waiting times and overall access to osteoporosis care in England.

Post-acute COVID syndrome (long COVID): What should radiographers know and the potential impact for imaging services.

OBJECTIVES: The COVID-19 pandemic caused an unprecedented health crisis resulting in over 6 million deaths worldwide, a figure, which continues to grow. In addition to the excess mortality, there are individuals who recovered from the acute stages, but suffered long-term changes in their health post COVID-19, commonly referred to as long COVID. It is estimated there are currently 1.8 million long COVID sufferers by May 2022 in the UK alone. The aim of this narrative literature review is to explore the signs, symptoms and diagnosis of long COVID and the potential impact on imaging services. KEY FINDINGS: Long COVID is estimated to occur in 9.5% of those with two doses of vaccination and 14.6% if those with a single dose or no vaccination. Long COVID is defined by ongoing symptoms lasting for 12 or more weeks post acute infection. Symptoms are associated with reductions in the quality of daily life and may involve multisystem manifestations or present as a single symptom. CONCLUSION: The full impact of long COVID on imaging services is yet to be realised, but there is likely to be significant increased demand for imaging, particularly in CT for the assessment of lung disease. Educators will need to include aspects related to long COVID pathophysiology and imaging presentations in curricula, underpinned by the rapidly evolving evidence base. IMPLICATIONS FOR PRACTICE: Symptoms relating to long COVID are likely to become a common reason for imaging, with a particular burden on Computed Tomography services. Planning, education and updating protocols in line with a rapidly emerging evidence base is going to be essential.

The challenges, coping mechanisms, and recovery from the initial waves of the COVID-19 pandemic among academic radiographers.

INTRODUCTION: The COVID-19 pandemic arrived in Europe in March 2020 and created major challenges across healthcare provision and for healthcare education programmes as well as having a major impact on society. Within the profession of Radiography changes in medical imaging, radiotherapy, and teaching practices have been reported along with the negative impact on radiographers and students. The aim of this study was to investigate key challenges relating to academic practice during the COIVD-19 pandemic; how radiography academics have coped and to identify recommendations for further support required to facilitate recovery of the academic faculty as the pandemic ebbs. METHODS: A survey was circulated using SurveyMonkey™ via personal, national and international networks, including the European Federation of Radiographer Societies (EFRS), to reach as many academic radiographers as possible. Open questions relating to the challenges of providing radiography education during the COVID-19 pandemic and the and coping strategies used were included. Thematic analysis was conducted using NVivo (QSR International, MA). RESULTS: 533 academic radiographers responded to the whole survey from 43 different countries, with 340 responses relating to challenges and 327 for coping strategies. The main themes for the challenges were clinical practice, communication with colleagues, lack of face to face, managing change, students (support), and staff support. The coping strategy themes were communication with colleagues, physical exercise, self-care and wellbeing. CONCLUSION: These data demonstrate a multitude of challenges for academic radiographers and the pressure they worked under during the first year of the COVID-19 pandemic was clear. However, the majority employed healthy coping strategies to help them deal with the pressure, uncertainty and trauma of the situation. IMPLICATIONS FOR PRACTICE: COVID-19 had a significant impact on academic radiographers and while many reported good strategies for coping, the level of pressure is unsustainable. This study highlights the need to support academic radiographers to ensure a sustainable workforce.

The risk of burnout in academic radiographers during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic created major challenges across society, healthcare provision and also for those delivering healthcare education programmes. Clinical placements were disrupted and, in many incidences cancelled. Higher education institutions were required to move completely to online delivery methods with little notice. This created significant additional workload, stress and the need to learn new skills at a time of great uncertainty. This study explored the risks of burnout in academic radiographers during the first 12 months of the pandemic. METHODS: A survey was circulated using SurveyMonkey™ via personal, national and international networks, including the European Federation of Radiographer Societies (EFRS), to reach as many academic radiographers as possible. Disengagement and exhaustion were measured using the Oldenburg burnout inventory. Descriptive statistics and a one-way ANOVA were used to analyse the quantitative data using STATA V16 (Statacorp, TA). RESULTS: 533 academic radiographers responded to the survey from 43 different countries. Mean disengagement was in the medium range and exhaustion was high for the total dataset. In a subset of countries with 10 or more responses, there was significant variation between countries, with the UK having highest mean exhaustion score and the UK, Ireland and France sharing the highest mean disengagement score. In the total dataset, 86% agreed workload had increased during the pandemic and 35% had considered leaving academia in the last year. CONCLUSION: These data demonstrate the stark reality of the impact of the COVID-19 pandemic on academic radiographers' workload, wellbeing, and intention to leave their roles. IMPLICATIONS FOR PRACTICE: COVID-19 has had a significant impact on academic radiographers and this study highlights the urgent need for remedial measures to better support academic radiographers in order to ensure a sufficient, and sustainable workforce.

Artificial intelligence in radiography: Where are we now and what does the future hold?

OBJECTIVES: This paper will outline the status and basic principles of artificial intelligence (AI) in radiography along with some thoughts and suggestions on what the future might hold. While the authors are not always able to separate the current status from future developments in this field, given the speed of innovation in AI, every effort has been made to give a view to the present with projections to the future. KEY FINDINGS: AI is increasingly being integrated within radiography and radiographers will increasingly be working with AI based tools in the future. As new AI tools are developed it is essential that robust validation is undertaken in unseen data, supported by more prospective interdisciplinary research. A framework of stronger, more comprehensive approvals are recommended and the involvement of service users, including practitioners, patients and their carers in the design and implementation of AI tools is essential. Clearer accountability and medicolegal frameworks are required in cases of erroneous results from the use of AI-powered software and hardware. Clearer career pathways and role extension provision for healthcare practitioners, including radiographers, are required along with education in this field where AI will be central. CONCLUSION: With the current growth rate of AI tools it is expected that many of the applications in medical imaging will continue to develop to more accurate, less expensive and more readily available versions moving from the bench to the bedside. The hope is that, alongside efficiency and increased patient throughput, patient centred care and precision medicine will find their way in, so we will not only deliver a faster, safer, seamless clinical service but also one that will have the patients at its heart. IMPACT FOR PRACTICE: AI is already reaching clinical practice in many forms and its presence will continue to increase over the short and long-term future. Radiographers must learn to work with AI, embracing it and maximising the positive outcomes from this new technology.

Understanding student radiographer attrition: Risk factors and strategies.

INTRODUCTION: Diagnostic student radiographer attrition is reported at 14%, 6% higher than the average for higher education, however, little research has been undertaken on this subject. This study explored risk factors for attrition and strategies that enabled these to be overcome. METHODS: A two-phase study was undertaken. Phase one: data for 579 former student diagnostic radiographers (468 completers and 111 non-completers) from 3 English universities were analysed. Logistic regression was used to estimate odds ratios and 95% confidence intervals for completion based on individual characteristics. Phase two: content analysis of data from an online survey of 186 current UK student diagnostic radiographers exploring their experiences was undertaken. RESULTS: Phase one: Attrition was 19%. Increased age, non A-level entry qualifications and poor academic performance were predictors of attrition (p < 0.005). Phase two: Challenges reported by groups identified as 'at risk' showed that for mature students and those with non-traditional entry qualifications, external responsibilities/pressures and financial pressures were likely to be the greatest cause of attrition and for younger students with traditional qualifications, academic difficulty and excessive workload were most significant. Scientific learning and academic writing were identified as the most common academic difficulties by all groups. Poor mental health may also be a risk factor. CONCLUSION: Although characteristics were identified that increased the chance of attrition, the study concluded that attrition is most likely to be multi-factorial. Academic and personal support were identified as key in students continuing their studies when they considered leaving. Clinical placement experience is likely to influence continuation decisions. IMPLICATIONS FOR PRACTICE: Transparency around course expectations and academic requirements together with ensuring high quality clinical placements may assist in reducing attrition.

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.

"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.

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 (#<3wks) (N = 9), and participants who had sustained a leg fracture more than one year previously (#>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 #<3wks demonstrated significant (p < 0.05) losses in ipsilateral TH BMD at 6 weeks from baseline 0.927 ± 0.137 g/cm2, to 0.916 ± 0.151 g/cm2 improving to 0.946 ± 0.135 g/cm2 (n.s) at 12 months following gradual return to normal function and weight-bearing activity. 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 #<3wks is not consistent with #>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.

The academic radiography workforce: Age profile, succession planning and academic development.

INTRODUCTION: Academia is one area of practice in which radiographers can specialise; they compile approximately 2% of the total radiography profession in the UK, but are highly influential and essential for the education and development of the workforce in addition to undertaking research. However, the academic environment is very different to clinical practice and a period of transition is required. METHODS: Data were collated to explore the age and retirement profile of the academic radiography workforce in the UK; to understand the research time allocated to this workforce; the time required to develop a clinical radiographer into an academic and the mentorship and succession planning provisions nationally. An online UK wide survey was conducted and sent to all 24 Universities delivering radiography education within the UK. RESULTS: Eighteen out of 24 Universities in the UK responded to the survey. Approximately 30% of radiography academics are due to retire over the next 10 years, with over 25% of radiographers who currently hold a doctorate qualification included within this figure. Those entering academia have notably lower qualifications as a group than those who are due to retire. Developing clinical radiographers into academics was thought to take 1-3 years on average, or longer if they are required to undertake research. CONCLUSION: There is vulnerability in the academic radiography workforce. Higher education institutions need to invest in developing the academic workforce to maintain research and educational expertise, which is underpinned by master's and doctorate level qualifications.

Patient-derived xenotransplants can recapitulate the genetic driver landscape of acute leukemias.

Genomic studies have identified recurrent somatic mutations in acute leukemias. However, current murine models do not sufficiently encompass the genomic complexity of human leukemias. To develop preclinical models, we transplanted 160 samples from patients with acute leukemia (acute myeloid leukemia, mixed lineage leukemia, B-cell acute lymphoblastic leukemia, T-cell ALL) into immunodeficient mice. Of these, 119 engrafted with expected immunophenotype. Targeted sequencing of 374 genes and 265 frequently rearranged RNAs detected recurrent and novel genetic lesions in 48 paired primary tumor (PT) and patient-derived xenotransplant (PDX) samples. Overall, the frequencies of 274 somatic variant alleles correlated between PT and PDX samples, although the data were highly variable for variant alleles present at 0-10%. Seventeen percent of variant alleles were detected in either PT or PDX samples only. Based on variant allele frequency changes, 24 PT-PDX pairs were classified as concordant while the other 24 pairs showed various degree of clonal discordance. There was no correlation of clonal concordance with clinical parameters of diseases. Significantly more bone marrow samples than peripheral blood samples engrafted discordantly. These data demonstrate the utility of developing PDX banks for modeling human leukemia, and emphasize the importance of genomic profiling of PDX and patient samples to ensure concordance before performing mechanistic or therapeutic studies.

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 < 0.05) and FG60 (42.6 ± 11.8 to 50.2 ± 12.8 µg·L-1, P < 0.05) but not for VIB (38.8 ± 15.1 to 36.6 ± 14.7 µg·L-1, P > 0.05). An increase in osteocalcin was observed 48 h after exercise (P < 0.05), which did not differ between exercise groups. C-terminal telopeptide of type 1 collagen was not affected by exercise. Blood lactate concentration increased during exercise for FG15 (0.6 ± 0.2 to 3.4 ± 1.2 mM) and FG60 (0.6 ± 0.2 to 3.3 ± 2.0 mM), but not for VIB (0.6 ± 0.2 to 0.8 ± 0.4 mM) (P < 0.05). Plasma creatine kinase increased by 55 ± 63% and 137 ± 119% 48 h after FG15 and FG60 (P < 0.05), but not after VIB (26 ± 54%, NS). In contrast to the minor elevation in osteocalcin in response to a single session of vibration exercise, both short and longer durations of small sided football acutely increased plasma P1NP, osteocalcin, and creatine kinase. This may contribute to favorable effects of chronic training on musculoskeletal health.

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.

Endemic fungal infections in solid organ and hematopoietic cell transplant recipients enrolled in the Transplant-Associated Infection Surveillance Network (TRANSNET).

BACKGROUND: Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations. METHODS: Fifteen institutions belonging to the Transplant-Associated Infection Surveillance Network prospectively enrolled SOT and HCT recipients with histoplasmosis, blastomycosis, or coccidioidomycosis occurring between March 2001 and March 2006. RESULTS: A total of 70 patients (64 SOT recipients and 6 HCT recipients) had infection with an endemic mycosis, including 52 with histoplasmosis, 9 with blastomycosis, and 9 with coccidioidomycosis. The 12-month cumulative incidence rate among SOT recipients for histoplasmosis was 0.102%. Occurrence of infection was bimodal; 28 (40%) infections occurred in the first 6 months post transplantation, and 24 (34%) occurred between 2 and 11 years post transplantation. Three patients were documented to have acquired infection from the donor organ. Seven SOT recipients with histoplasmosis and 3 with coccidioidomycosis died (16%); no HCT recipient died. CONCLUSIONS: This 5-year multicenter prospective surveillance study found that endemic mycoses occur uncommonly in SOT and HCT recipients, and that the period at risk extends for years after transplantation.

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.

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.