Cerebral perfusion computerized tomography: influence of reference vessels, regions of interest and interobserver variability.

Introduction: There are still no standardized guidelines for perfusion computerized tomography (PCT) analysis.

Methods: A total of 61 PCT studies were analyzed using either the anterior cerebral artery (ACA) or the middle cerebral artery (MCA) as the arterial reference, and the superior sagittal sinus (SSS) or the vein of Galen (VG) as the venous reference. The sizes of regions of interest (ROI) were investigated comparing PCT results obtained using a hemispheric ROI combined with vascular pixel elimination with those obtained using five smaller ROIs located over the cortex and basal ganglia.