S.J. Hopkins

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 (<25 kg/m(2)) (n=48), overweight (25-30 kg/m(2)) (n=26), and obese (>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.

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 BMIs ranging from 18.5 to 45.9 kg/m(2) 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 (<25 kg/m²; n = 76), overweight (25-30 kg/m²; n = 36), and obese (>30 kg/m²; n = 32) BMI groups, respectively, were total BMD (g/cm(2)): 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.

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.

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.

“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.

Response to ‘Precision Error in Dual-Energy X-Ray Absorptiometry Body Composition Measurements in Elite Male Rugby League Players’

Dual-energy X-ray absorptiometry (DXA) has long been regarded as the gold standard modality for the measurement of longitudinal changes in bone mineral density and body composition on the basis of its low doses of ionizing radiation and high levels of equipment precision. Although equipment precision is acceptable in the region of 1.5% (1), it is acknowledged that other factors, including differences in participant positioning and scan analysis, can markedly increase precision error in serial in vivo measurements. Recent studies of short-term in vivo precision for DXA bone mineral density in GE Lunar Prodigy have demonstrated that precision error is exacerbated in obese participants (2), and it has been suggested that this may be