Clinical Utility of Computer-Aided Diagnosis of Vertebral Fractures From Computed Tomography Images.

Osteoporotic vertebral compression fractures (VCFs) are a risk factor for morbidity and mortality, frequently asymptomatic and often present in computed tomography (CT) scans performed for unrelated conditions. Computer-aided diagnosis (CAD) of VCF from such images can potentially improve identification and treatment of osteoporosis. This single-blinded, single tertiary center study compared a CAD (Zebra Medical Vision®) to an adjudicated imaging specialist reevaluation using a retrospective consecutive sample of abdominal and thoracic CT scans (n = 2357) performed as part of routine care. Subjects over 50 years between January 1, 2019 and May 12, 2019 were included. Duplicates and unanalyzable scans were excluded resulting in a total of 1696 CT scans. The sensitivity, specificity, and accuracy were calculated for all VCF and for Genant grades 2 or 3 (ie, height loss of >25%) using imaging specialist as the gold standard. Prestudy VCF reporting by hospital-rostered radiologist was used to calculate the number of scans needed to screen (NNS) to detect one additional VCF using CAD. Prevalence of any VCF was 24% (406/1696) and of Genant 2/3 VCF was 18% (280/1570). The sensitivity and specificity were 54% and 92%, for all fractures, respectively, and 65% and 92% for Genant 2/3 fractures, respectively. Accuracy for any VCF, and for detection of Genant 2/3 VCF, was 83% and 88%, respectively. Of 221 CAD-detected VCFs, 133 (60.2%) were reported prestudy resulting in 88 additional fractures (72 Genant 2/3) being identified by CAD. NNS to detect one additional VCF was 19 scans for all fractures and 23 for Genant 2/3 fractures. Thus, the CAD tested in this study had a high specificity with moderate sensitivity to detect incidental vertebral fractures in CT scans performed for routine care. A low NNS suggests it is an efficient tool to assist radiologists and clinicians to improve detection and reporting of vertebral fractures. © 2020 American Society for Bone and Mineral Research (ASBMR).

Validation of longitudinal DXA changes in body composition from pre- to mid-adolescence using MRI as reference.

Dual-energy X-ray absorptiometry (DXA) has been used extensively for bone mineral density and body composition assessments. Surprisingly, the role of DXA in monitoring changes in children's body composition, using direct imaging methods such as magnetic resonance imaging (MRI) as reference, is still yet to be validated. We aimed at validating the use of DXA in monitoring change in the thigh lean soft tissue mass (LSTM) and fat mass (FM) when compared with thigh skeletal muscle mass (SM) and FM, measured using MRI as the reference standard, from childhood to midadolescence. At baseline, 22 healthy children (16 boys and 6 girls) aged 8-11yr were included, and then recalled at pubertal stage Tanner2-Tanner4. LSTM-DXA and FM-DXA of the mid-third femur and SM-MRI and FM-MRI of the same region were measured on the same day. The same protocol was repeated 26-48mo later. At baseline, DXA overestimated LSTM-DXA on average by 222g (95% confidence interval [CI]: 33-410g) with a concordance C-LSTM=0.576. FM-MRI and FM-DXA were not significantly different (95% CI=213 to 199g, the C-FM=0.907). At follow-up, change in LSTM-DXA and FM-DXA were not significantly different to change in SM-MRI and FM-MRI, respectively (95% CI of the difference was -278 to 208g for LSTM, and -148 to 236g for FM). The coefficient of concordance between the 2 techniques was 0.88 for both LSTM and FM. This study validates the use of DXA in monitoring changes in LSTM and FM in children, confirming its significant potential in clinical and research roles in pediatric body composition.

Prediction of appendicular skeletal and fat mass in children: excellent concordance of dual-energy X-ray absorptiometry and magnetic resonance imaging.

BACKGROUND: Body composition studies in children have great potential to help understand the aetiology and evolution of acute and chronic. diseases. AIM: To validate appendicular lean soft tissue mass (LSTM) and fat mass (FM) measured using dual energy X-ray absorptiometry (DXA), with magnetic resonance imaging (MRI) as the reference standard, in healthy peri-pubertal adolescents. DESIGN: Peri-pubertal Caucasian children (n = 74) aged 11-14 years were evaluated. DXA LSTM and FM of the mid third femur were measured and skeletal muscle mass (SM) and FM of the same region were measured on the same day by MRI. RESULTS: There was a strong correlation between MRI SM and DXA LSTM (r2 = 0.98, index of concordance [C] = 0.91). DXA estimation of LSTM exceeded MRI SM by a mean of 189 g, from 6-371 g (p < 0.0001). The discordance between DXA and MRI significantly increased with the absolute value (r = 0.27; p = 0.024). FM was highly correlated (r = 0.98) with a high index of concordance (C = 0.97). CONCLUSION: This study validates the use of DXA in LSTM measurement in children, confirming its potential in clinical and research roles in paediatric diseases affecting and related to body composition.

Bone mineral density, body mass index and cigarette smoking among Iranian women: implications for prevention.

BACKGROUND: While risk factors of osteoporosis in Western populations have been extensively documented, such a profile has not been well studied in Caucasians of non-European origin. This study was designed to estimate the modifiable distribution and determinants of bone mineral density (BMD) among Iranian women in Australia. METHODS: Ninety women aged 35 years and older completed a questionnaire on socio-demographic and lifestyle factors. BMD was measured at the lumbar spine (LS) and femoral neck (FN) using DXA (GE Lunar, WI, USA), and was expressed in g/cm2 as well as T-score. RESULTS: In multiple regression analysis, advancing age, lower body mass index (BMI), and smoking were independently associated with LS and FN BMD, with the 3 factors collectively accounting for 30% and 38% variance of LS and FN BMD, respectively. LS and FN BMD in smokers was 8% lower than that in non-smokers. Further analysis of interaction between BMI and smoking revealed that the effect of smoking was only observed in the obese group (p = 0.029 for LSBMD and p = 0.007 for FNBMD), but not in the overweight and normal groups. Using T-scores from two bone sites the prevalence of osteoporosis (T-scores

Limited utility of clinical indices for the prediction of symptomatic fracture risk in postmenopausal women.

Bone mineral density (BMD) is the primary predictor of fracture, and is utilised in the definition of osteoporosis. Mass screening for osteoporosis is, however, currently not recommended. The primary objective of this study was to develop, validate and assess a simple, non-invasive scoring system to identify women at high risk of fracture. Using baseline data of the Dubbo Osteoporosis Epidemiology Study, a sample of 1256 women aged 60 or above was randomly divided into a development cohort (n=846) and a validation cohort (n=410). Low BMD was evaluated by DXA, with respect to 2.0 or 2.5 SD below the mean for young normal women at the femoral neck and lumbar spine. A logistic regression model was used to derive a predictive score, "DOEScore", in the development cohort, and the performance of this score was then assessed in the validation cohort. Incident fractures over 9395 person-years (median of follow-up duration: 8.4 years) were identified by X-ray records. Approximately 57% and 40% of women (in both cohorts) had T-scores less than -2.0 and greater than -2.5, respectively. Only age, body weight, and previous fracture were significantly related to BMD at both the femoral neck and lumbar spine. These three variables were used in the development of the DOEScore. When applied to the validation cohort, the sensitivity and specificity of DOEScore were 0.82 and 0.52, respectively, for selecting women with T-scores less than -2.5; the area under the receiver operating characteristic (ROC) curve was 0.75. These goodness-of-fit indices were comparable to, or better than, those obtained by the FOSTA, SOFSURF and ORAI score systems. However, neither the DOEScore nor other score systems reliably identify women with incident fractures; for DOEScore, the sensitivity and specificity were 0.52 and 0.49, respectively, with an area under the ROC curve of 0.48. Clinical risk scores can be used to identify women likely to have low BMD (albeit with low specificity), but they are not a useful tool to identify women who will have a fracture.

The diagnostic role of dual femur bone density measurement in low-impact fractures.

A high correlation has been documented between the left and right femoral bone mineral densities in the normal population. This suggests that dual femur measurements are not justified in clinical practice. This study evaluated whether this premise holds for subjects who have lost bone mass and have sustained fractures with minimal trauma. Seventy-eight women aged 31-83 years (mean=66 years) with previous low-impact fractures had both proximal femora measured using dual-energy X-ray absorptiometry. There were significant correlations between values in the left and right total hip (TH) (r=0.95; p<0.05) and in the left and right femoral neck (FN) (r=0.90; p<0.05). The mean differences between the left and right TH and FN densities were not significant. However, the range of the limits of agreement for the TH (-0.074 to 0.086 g/cm2) and FN (-0.115 to 0.105 g/cm2) were greater than the 95% confidence interval for true change for the TH (0.05 g/cm2) and FN (0.07 g/cm2). Any longitudinal BMD assessment therefore needs to measure the same proximal femur to get a reliable comparison. A one-tailed analysis showed that for the TH, 7.5% of subjects had a T-score discordance greater than or equal to 0.5 and 0.5% had a T-score discordance greater than or equal to 1. For the FN, 9% had a T-score discordance greater than or equal to 0.5 and 2.5% had a T-score discordance greater than or equal to 1. The use of dual femur measurements increases the diagnostic yield by about 10% in subjects with prior minimal trauma fractures.

Reproducibility and concordance in quantitative ultrasound measurements between densitometers: a comparative study.

Although calcaneal quantitative ultrasound (QUS) is an independent predictor of osteoporotic fracture, its role in monitoring changes in bone status remains limited because of its relatively poor precision compared to the rate of bone loss. Recently, imaging QUS has been developed that can standardize the region of interest in the calcaneus with the potential of improving precision. We assessed the concordance and precision of an imaging QUS scanner (UBIS 5000) and a nonimaging scanner (LUNAR Achilles+) in 52 subjects aged between 27 and 79 yr. Each subject had duplicate measurements on each scanner on the same day. The measurements were broad-band ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index, which was derived from BUA and SOS. Precision was evaluated by the standard error of measurement (SEM) and within-subject coefficient of variation (CV). There was significant correlation between the two scanners in all QUS measurements (r > 0.8; p < 0.001); however, BUA and SOS measurements by the UBIS were significantly lower than by the Achilles+. The SEM of BUA (0.6 dB/MHz) and SOS (2.7 m/s) in the UBIS were significantly lower (p < 0.001) than the Achilles+ (1.4 dB/MHz for BUA and 6.3 m/s for SOS). When the SEM was expressed as the percentage of the mean, there were no significant differences in CVs between UBIS (0.9% for BUA and 0.2% for SOS) and Achilles+ (1.2% for BUA and 0.4% for SOS) scanners. The SEM of stiffness index derived by UBIS was not significantly different from that derived by the Achilles+. These data suggest that although there are systematic differences between the UBIS and Achilles+ scanners in QUS measurements, the precision of the two instruments is equivalent.