EFFECT OF SYMPATHETIC BLOCK DEMONSTRATED BY TRIPLE-PHASE BONE-SCAN

The triple-phase bone scan is frequently used in the diagnosis of refl ex sympathetic dystrophy although the etiology of the abnormal finding s is not well established. This study evaluated the effect of increase d blood flow secondary to sympathetic block on the triple-phase bone s can. In 15 reflex sympathetic dystrophy patients, all of whom had sign ificant relief with sympathetic block, baseline and postsympathetic bl ock bone scans were analyzed. There was a significant linear relations hip between change in counts from baseline to postsympathetic block on the blood pool image and bone uptake image. As the blood pool and bon e uptake counts increased, the likelihood of typical reflex sympatheti c dystrophy findings on visual inspection also increased. These result s strongly support the concept of increased vascular flow as the cause of increased periarticular uptake.