Significance of skeletal uptake detected on radionuclide renal perfusion studies

Since the introduction of Tc-99m labeled radiopharmaceuticals, flow studies have become a useful and readily performed component of renal nuclear medicine examinations. In addition to detecting aberrations of renal perfusion, a number of extrarenal abnormalities may also be surreptitiously detected. Three cases of hyperperfused skeleton, an extremely unusual finding which complements two previous reports in the literature, have recently been observed. All three of the patients, as well as the two previously described, had underlying neoplastic abnormalities. The appearance of perfused skeleton should therefore be recognized as suggesting the presence of underlying neoplastic disease. Considerable interest as to the etiology and magnitude of the increased skeletal perfusion exists. Measurements of normal marrow and osseous perfusion have been reviewed in order to better appreciate the magnitude of increase required for skeletal visualization on renal flow studies. Some considerations as to the etiology of this increase are offered.