Accuracy of visually estimated bone mineralization in routine radiographs of the lower extremity

In order to determine the accuracy of reports of demineralization based on observations of routine radiographs of the peripheral skeleton, pairs of radiographs with known difference in bone mineral density (BMD) were shown to a panel of medically qualified observers. No significant difference in the rate of correct identification of osteopenia of metaphyseal and diaphyseal bone was observed. Experienced observers were more accurate than their juniors. The probability of correct identification was greater than 0.5 at all levels of BMD difference, and in general increased with increasing BMD differences, reaching a probability of 0.7 at a BMD difference of 30%. The probability increased considerably when the assessment relied on the majority vote of three or more observers. It is concluded that it is inadvisable for a single observer to judge BMD when studying routine X-ray studies of the peripheral skeleton.