Femoral Neck Dual X-ray Absorptiometry Research Articles

Computed Tomography of the Chest as a Screening Tool for Low Bone Mineral Density.

Computed tomography (CT) Hounsfield units (HU) recently emerged as a promising screening tool for low bone mineral density (BMD). We hypothesized that CT HU measurements of the thoracic spine would significantly and positively correlate with dual X-ray absorptiometry (DXA) BMD scans of the femoral neck. The study included patients with DXA scans and thoracic CT scans at the Walter Reed National Military Medical Center. One author, blinded to the DXA scans, measured HU from the cancellous bone in T4 vertebrae. Another author statistically compared femoral neck DXA T-scores to the CT HU measurements. The study included 145 patients with CT scans and femoral neck DXAs. The osteoporotic and osteopenic groups had a significant difference in HU measurements compared to the normal group within the study (P < .0001 and .002, respectively). A low BMD screening value of 231 HU provided a sensitivity of 90.1% and negative predictive value of 85.7%. Thoracic vertebrae HU measurements correlate with a low BMD of the femoral neck as determined by DXA T-scores. A high sensitivity and negative predictive value was achieved with a screening value of 231 HU. Utilization of chest or thoracic spine CT imaging as a screening method provides a quick and available screening tool for assessing low BMD in patients with these scans.Level of Evidence: III (Diagnostic).

Estimation of Whole-Body and Appendicular Lean Mass from Spine and Hip Dual Energy X-ray Absorptiometry: A Cross-Sectional Study.

Whole-body dual X-ray absorptiometry (DXA) accurately measures lean mass but is not routinely used in clinical practice. Hip and spine DXA are used in the diagnosis of osteoporosis, and with the common co-occurrence of sarcopenia with osteoporosis, regional DXA scans provide an opportunity for assessment of lean mass. The aim of this study is to develop predictive equations for the estimation of whole-body lean mass (WBLM), appendicular lean mass (ALM) and whole-body fat mass (WBFM) from regional DXA scans. A total of 2427 participants (ages 20-96year; 57.7% men) from the Geelong Osteoporosis Study who underwent both regional and whole-body DXA were included in the analysis. Using forward stepwise multivariable linear regression, percentage fat (spine%fat, hip%fat) values from lumbar spine and femoral neck DXA were used in combination with clinical data to develop and validate equations for the estimation of WBLM, WBFM and ALM. Mean age was 53.5year (± 19.2), weight 78.2kg (± 15.4), height 169.6cm (± 9.4), WBLM 50.4kg (± 11.1), ALM 22.8kg (± 5.4) and WBFM 24.3kg (± 10.4). Spine%fat (r = 0.21) and hip%fat (r = - 0.34) were correlated with whole-body lean mass (p < 0.001). Final predictive equations included age, sex, weight, height, spine%fat, and hip%fat and possessed high predictive value (Adj R2 0.91-0.94, RMSE 1.60-2.84kg). K-fold cross-validation methods produced median root mean square error (RMSE) ranging from 1.59 to 2.81kg for the three models. Regional DXA scans of the spine and hip can be used to estimate whole-body and appendicular lean mass, to assist in the identification of low muscle mass.

Does Quantitative Ultrasound at the Calcaneus Predict an Osteoporosis Diagnosis in Postmenopausal Women from the Silesia Osteo Active Study?

The aims of the study were to assess the clinical conformity between quantitative ultrasound (QUS) and densitometry with use of the standard World Health Organization T-score thresholds to determine optimal diagnostic cutoff values for QUS T-scores in different age groups. Three hundred sixty-five postmenopausal Caucasian women were enrolled into the study and divided into two age groups (<65 y and ≥65 y). Skeletal status was assessed using QUS measurements at the calcaneus and bone densitometry at the spine and proximal femur (Hologic Explorer, Bedford, MA, USA). QUS measurement results expressed as the stiffness index (SI) correlated significantly with both femoral neck bone mineral density (r = 0.51, p < 0.0001) and lumbar spine bone mineral density (r = 0.52, p < 0.0001). On the basis of receiver operating characteristic curve analyses, the thresholds for correspondence between QUS T-score values and T-score –2.5SD in dual X-ray absorptiometry (DXA) were established. They ranged between –1.63SD and –1.70SD in relation to femoral neck DXA and between –1.22SD and –1.51SD in relation to lumbar spine DXA, depending on age category. In conclusion, the study described here confirmed that QUS measurements at the calcaneus may provide information comparable to DXA examinations at the femoral neck and lumbar spine in postmenopausal women.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P30. Thoracic computed tomography Hounsfield unit measurement accurately predicts low bone mineral density of the femoral neck

BACKGROUND CONTEXT Osteoporosis remains a major cause of morbidity and mortality, despite increasing efforts among provider organizations to promote awareness and screening. Recent attention has turned to the opportunistic utilization of Hounsfield unit (HU) measurements from computed tomography (CT) as a potential screening method for low bone mineral density (BMD). We hypothesized that thoracic spine CT HU measurements will correlate with BMD measurements conducted with dual X-ray absorptiometry (DXA) scans of the femoral neck. PURPOSE To compare thoracic spine HU and femoral neck T-scores determined by DXA, and determine the accuracy with which thoracic HU values estimate central BMD. STUDY DESIGN/SETTING Retrospective review of patients with applicable imaging. PATIENT SAMPLE Fifty-six patients with both computed tomography scans including the thoracic spine obtained for any indication, and dual X-ray absorptiometry T-scores of the femoral neck. METHODS Patients with thoracic CT and DXA scans at one institution were included in the study. Hounsfield units were manually measured from the cancellous bone in T4 vertebrae by one author blinded to DXA scans. HU measurements were compared with femoral neck DXA t-scores. A receiver operator characteristic curve (ROC) with associated dataset was utilized to aid in determining maximum screening HU values for sensitivity and specificity. RESULTS Fifty-six patients with 58 CT scans and femoral neck DXAs were included in the study. The average HU in the osteoporotic group was significantly lower than the normal group (148.89HU±56.53HU vs. 217.56HU±65.69HU, respectively; p CONCLUSIONS Thoracic vertebrae HU measurements correlate with low BMD of the femoral neck as determined by DXA scan T-score. Screening values of 218 HU captured over 95% of those with low BMD, with sensitivity of 90%. Opportunistic utilization of thoracic HU as a screening method provides a simple, quick, and easily assessable screening tool for assessing low BMD.

The ultrasonic assessment of osteopenia as defined by dual X-ray absorptiometry

Dual X-ray absorptiometry (DXA) studies of bone mineral density (BMD) of the lumbar spine and femoral neck were compared with measurements of broadband ultrasonic attenuation (BUA) and velocity of ultrasound (VOS) in the calcaneus in 300 pre- and postmenopausal women (mean age 53 years). The women were referred for evaluation of possible osteopenia as defined by DXA. The ability of ultrasound measurements to predict osteopenia in women was compared with the ability of lumbar spine and femoral neck DXA scans to predict osteopenia in the hip and spine. A new ultrasound parameter obtained by combining BUA and VOS (combined attenuation and velocity (CAV)) was also evaluated. Linear regression analysis of the three ultrasound parameters and lumbar spine and femoral neck BMD gave weak but statistically significant correlations (r = 0.45-0.54). The correlation between spine and femoral neck BMD was statistically significantly better (r = 0.72). Receiver-operating characteristic (ROC) analysis was used to investigate the sensitivity and specificity of ultrasound measurements in predicting patients with osteopenia. The areas under the ROC curves ranged from 0.64 to 0.75 and ultrasound parameters were shown to be poor at predicting osteopenia as defined by DXA. The ability of lumbar spine and femoral neck DXA measurement to predict osteopenia in the hip and spine, respectively, was statistically significantly better than any of the ultrasound parameters. Ultrasound measurements in the calcaneus did not appear to identify accurately patients with osteopenia defined by DXA measurements of bone density in the axial and appendicular skeleton.