Osteopenia and osteoporosis in postmenopausal women. Assessment by radiogrammetric measurement

To compare the ability of the medial cortical thickness ratio to the width of the second metacarpal bone at the midshaft (MCR) in discriminating patients as normal, osteopenic or osteoporotic.

MCR was calculated from radiographs of 120 postmenopausal women. By dual-energy X-ray absorptiometry, the mineral density was measured in the lumbar spine, the wrist and the femoral neck. Patients were grouped in accordance with the diagnostic criteria of WHO on the basis of t-scores. MCR values were compared with t-scores and the ability of the MCR technique in discriminating the patient groups was evaluated.

Analysis of radiogrammetric data revealed significant differences in MCR value between the 3 groups. The MCR was lower in patients with osteoporosis and osteopenia compared with the normal group. The mean value of MCR was also slightly lower in patients with osteoporosis than in those with osteopenia. Accuracy assessment (ROC analysis) of MCR in the discrimination of patients with osteoporosis showed that test accuracy was acceptable, but less accurate than spinal, wrist and femoral neck t-scores. Compared with t-scores, this test was found to fairly discriminate those with and without osteopenia.

The MCR method can discriminate patients as osteoporotic or normal. However, it seems that the MCR method should not be used for decisions concerning treatment of osteoporosis because of its low accuracy and thereby a risk for misclassification.