Total body and regional bone mineral densitometry (BMD) and soft tissue measurements: Correlations of BMD parameter to lumbar spine and hip

Bone loss in men and women seems to differ according to the skeletal region s or particular areas being evaluated. Dual energy X-ray absorptiometry (DX A) is the method of choice for measuring total body and regional bone miner al area density (BMD). The aim of the study was to evaluate the importance of DXA measurements of total body in relation to lumbar spine and hip in di fferent scan beam designs. In 300 patients, ages 43-80 years, lumbar spine, hip, total body and regional bone mineral area density, and soft tissue me asurements were performed on all subjects in the supine position on a QDR 2 000 using single beam (SB) and fan beam (FB). Short-term precision errors w ere 0.7% (SB) and 1.2% (FB) for BMD total of the total body and between 1.2 % and 8.0% for soft tissue measurements. All mid-term precision errors of B MD total, right and left leg, and pelvis were below 2.0% with SE and FB, wh ereas precision errors of thoracic and lumbar spine varied depending on the scan mode being applied. In contrast, all mid-term precision errors of sof t tissue measurements were greater (2.6-11.0%). All SE values of BMD and so ft tissue measurement were significantly higher than FB values, except for BMD values of the head, thoracic spine, and pelvis. Furthermore, BMD total of the total body scan correlated significantly (P < 0.001) with all subreg ional parameters with best "r"-values (0.86-0.92) for the right and left le g in SE and FB design. In addition, there were excellent correlations (r > 0.94, P < 0.001) between the right and left legs (SB and FB) or arms (SB). There were also highly significant correlations between the lumbar spine (o r hip) and total body, being best for the subregional thorax. Our data demo nstrate short-and mid-term precision errors of BMD with reproducible result s for most areas in SE and FB design, whereas soft tissue measurements vary depending on the area being measured. Furthermore, there is a close relati onship between BMD values of total body total and subregional parameters an d lumbar spine and hip scans, respectively.