[Experimental studies on the accuracy of mineral content assessment in spongiosa bone using quantitative CT (single energy measurement)].

The mineral content of 42 lumbar vertebral bodies (using a phantom to simulate living conditions) and of 30 calcanea was measured by quantitative CT. The bones were subsequently ashed and the calcium and fat content determined chemically. The mineral concentration (calibrated against a K2HPO4 solution) showed good correlation with the calcium content (for the lumbar vertebrae, r = 0.963 and for the calcanea r = 0.94. The fat content of the bone marrow leads to a systematic under-estimation of the mineral content, if one uses single energy CT measurements. The experimental findings can be satisfactorily treated in a quantitative way with the help of a model which contains the three components of spongy bone (mineral, fat and fat-free connective tissue.