[X-ray photodensitometric study of the second metacarpal--a new method of evaluation of metabolic bone diseases].

For the purpose of mass screening of metabolic bone diseases, the usefulness of X-ray photodensitometry should be reappraised. The optical density pattern of the second metacarpals was measured with a video camera, and was processed by a computer to be calibrated and adapted to an elliptical bone model. The computer calculated the optimal bone mineral distribution in the bone model to reproduce the original density pattern. The bone was evaluated in terms of the bone mineral mass, the cortical bone mineral density and the second moment of inertia. With these parameters, this system provides a method of quantitative as well as qualitative evaluation of metabolic bone diseases. Osteoporosis revealed the highest physical efficiency in bone mineral distribution. Inefficient distribution shown in renal osteodystrophy was attributed to the malfunction in the control system of bone remodeling metabolism.