Evaluation by microdensitometry and dual energy X-ray absorptiometry of changes in bone metabolism after gastrectomy

We used microdensitometry (MD) and dual energy X-ray absorptiometry (DXA) to evaluate impaired bone metabolism in 79 patients who had undergone gastrectomy. With MD, radiographs are simultaneously taken of the second metacarpal bone and an aluminum step-wedge, and the images were analyzed by computer. DXA was used to measure the bone mineral density of the second through fourth vertebrae and the estimated volumetric bone mineral density (EstVBMD) was assessed. Significant positive correlations were obtained between EstVBMD as determined by DXA and metacarpal index (MCI) (r = 0.413, P < 0.01), peak of the cortex (GSmax) (r = 0.362, P < 0.05), peak of the middle portion of the bone marrow (GSmin) (r = 0.412, P < 0.01), and metacarpal bone mineral density (mBMD) (r = 0.413, P < 0.01) as determined by MD. When EstVBMD was compared with MCI, GSmax, GSmin, and mBMD according to sex, age, type of operation, and interval after operation, generally similar trends were obtained. We conclude that the determination by MD of various indices of bone metabolism is useful in the diagnosis of osteopathy after gastrectomy.