[Bone density measurements by computer tomography (author's transl)].

The suitability of the E.M.I. mark I computer scanner for carrying out bone densitometry has been tested, using the forearm. Within the region of interest there was an almost linear relationship between CT densities and the concentration of the bone equivalent substance K2HPO4. By means of a special computer programme, the spongiosa and cortex of both forearm bones could be analysed quantitatively. The reproducibility of the results (coefficient of variation 5%) was similar to that of other procedures in current use. The advantage of the method lies in the fact that it is possible to estimate the spongiosa and cortex separately. Investigations on patients with normal bones have shown that senile demineralisation affects the cortex most severely. On the other hand, in renal osteopathies of chronically dialysed patients, demineralisation in the forearm predominantly involves the spongiosa.