Quantitative computed tomography of vertebral spongiosa: A sensitive method for detecting early bone loss after oophorectomy (reprinted from Ann Intern Med vol 97, pg 699-705, 1982)

We assessed serially the bone mineral loss in 37 premenopausal women for 24 months after oophorectomy and determined the dose-response for conjugated estrogen therapy in preventing this loss. Spinal cancellous bone was measur ed by quantitative computed tomography and measurement of appendicular cort ical bone by radial photon absorptiometry and metacarpal radiogrammetry, Fo r the placebo and low-dose treatment groups, the mean annual bone mineral l osses were 7% to 9% from the vertebral spongiosum and 1% to 3% from the per ipheral cortex. The correlation between axial and appendicular loss was wea k (r = 0.581), precluding a reliable estimate of spinal loss from periphera l measurements. For the maximal-dose group (0.6 mg/d), the mean annual bone mineral losses were less than 0.5% from the axial and appendicular sites, and were not significant. The results indicate that spinal quantitative com puted tomography provides a highly sensitive measurement of bone mineral lo ss after oophorectomy, that bone mineral loss is five- to sevenfold greater from the spinal spongiosum than from the appendicular cortex, and that con jugated estrogen in doses of less than 0.6 mg/d are inadequate to prevent t he vertebral mineral loss.