Assessment of regional cerebral blood flow (rCBF) is useful in the evaluation of cerebral vascular disease. However, a single resting study has limitations in that a normal rCBF may be present with diminished cerebral vascular flow reserve and regions of decreased rCBF may be seen with diaschisis or selective neuronal loss and an intact vascular supply. To help differentiate these conditions a stress rCBF study can be obtained following the administration of vasodilatory stimulus. The topic of this review is the discussion of single photon emission computed tomography (SPECT) and vascular intervention, primarily, acetazolamide (Diamox, Lederle Laboratory Division, Pearl River, NY) augmented SPECT in the evaluation of cerebral vascular disease.