Increased extremity uptake on three-phase bone scans caused by peripherally induced ischemia prior to injection

During arterial flow scintigraphy, increased tracer uptake in the upper extremity has been noted secondary to induced ischemia distal to blood-pressure cuffs and simple tourniquets, employed prior to the injection. We prospectively studied 68 patients undergoing three-phase bone scintigraphy to evaluate the frequency and magnitude of this artifact. The results showed that when a blood-pressure cuff was applied virtually all patients demonstrated increased activity in the extremity of cuff application. When a simple rubber tourniquet was applied few patients demonstrated the artifact. Only one patient, a case of reflex sympathetic dystrophy syndrome, had increased uptake on blood-pool and skeletal-phase images. We recommend that in flow studies of the hands, wrists, and forearms, blood pressure cuffs not be employed and that at least 3 min should elapse between release of the occlusive device and injection. Asymmetry of flow under these conditions is unlikely to be artifact.