ACCURACY OF LATERAL DUAL-ENERGY X-RAY ABSORPTIOMETRY FOR THE DETERMINATION OF BONE-MINERAL CONTENT IN THE THORACIC AND LUMBAR SPINE - AN INVITRO STUDY

Lateral scanning with dual energy X-ray absorptiometry (DXA) was under taken on 153 thoracic and lumbar vertebral bodies from nine individual s (mean age 67; range 34-92 years) to establish their bone mineral con tent (BMC). All specimens were subsequently de-fatted and ashed to com pare ash weight with BMC of the T1 to L5 segments. Linear regression a nalysis indicated a higher correlation between BMC and measured ash we ights for each vertebral column (range: r = 0.97-0.99), with error ana lysis for all vertebrae tested showing a standard error of 0.40 g, or 10.8%. For the L2-4 segments the accuracy error was 0.50 g or 7.9%. In both cases there was a mean trend towards underestimation of ash weig ht. Mean BMC values of the T1 to T5 segments were similar before a pro gressive increase caudally. These data affirm the utility of DXA for d etermining bone mineral content in the vertebral column across wide ra nges of age, and segmental and bone density.