The comparative value of bone scintigraphy and computed tomography in determining bone involvement by soft-tissue sarcomas.

In seventeen patients with a soft-tissue sarcoma, bone scintigrams were found to be more useful than computed tomograms for evaluating bone involvement. The scintigrams had higher predictive value and higher sensitivity, as there were no false-negative or false-positive scintigrams, while there were three false-positive computed tomograms. Accurate scintigraphy requires the use of high-resolution static gamma-camera images that show the tangential relationship between tumor and bone. The images that are usually made in surveying the skeleton for metastatic disease--routine whole-body bone scans, or even gamma-camera images that provide only anterior and posterior views--are inadequate. They did not demonstrate the true relationship of the tumor to bone in the patients in this study when activity within the tumor itself was superimposed over bone. In such patients, properly selected oblique views sometimes showed that the tumor was clearly separate from normal bone activity. Determination of the relationship of the soft-tissue tumor to bone is an important part of the accurate anatomical staging that is required to select appropriate surgical management.