Early dynamic bone-imaging as an indicator of osseous blood flow. 1 Its clinical application in evaluating the vascularity of the femoral head.

The dynamic bone scans consisted of sixty-one-second images of both femoral heads, recorded immediately after the injections of technetium 99-labeled methylene diphosphonate. The counts per second were plotted against time to give time-activity curves for each of the femoral heads. The time-activity curves were integrated and then divided by the time-span to give average total counts per unit of time. In order to determine whether the blood flow to the diseased femoral head was decreased or increased, ratios were calculated using the values from the regions of interest on the affected side as the numerator and the values from the analogous regions of interest on the non-affected side as the denominator. The value for the ratios was less than 0.91 in a group of patients, with the following clinical diagnoses: three with femoral prosthesis of the hip, four with femoral neck fracture (Garden Stage IV), and three patients with avascular necrosis of the femoral heads. This non-invasive technique is suggested to evaluate the vascularity of a bone lesion.