Dynamic SPECT with Xe-133: regional cerebral blood flow in patients with unilateral cerebrovascular disease: concise communication.

To validate xenon-133 dynamic single photon emission tomography (SPECT) clinically, 74 patients were examined. Strictly unilateral cerebrovascular disease was confirmed in 47 patients by clinical history and by transmission computerized tomography (TCT) and contrast angiography. Twenty-seven were excluded, considered normal. SPECT flow maps were evaluated visually (against TCT) or by automated region of interest (ROI) techniques (12 areas per slice) to measure area flow (AF) (ml/100 g-min) and interhemispherical area flow ratios (AR). These were compared with normal values. Minimum AF in affected hemisphere decreased, and AR-to-normal difference increased, with the severity of the disease. Visually, low-flow areas were detected twice as frequently in SPECT as areas of low density of TCT. In reversible episodes, sensitivity of AF alone ws significantly below the sensitivity of combined evaluation of flow and ratio.