SPECT IN PATIENTS WITH CORTICAL VISUAL-LOSS

Single-photon emission computed tomography (SPECT) with Tc-99m-hexamet hyl propyleneamine oxime (HMPAO) was used to investigate changes in ce rebral blood flow in seven patients with cortical visual impairment. T raumatic brain injury (TBI) was the cause of cortical damage in two pa tients, cerebral ischemia in two patients and carbon monoxide (CO) poi soning, status epilepticus and Alzheimer's Disease (AD) each in three separate patients. The SPECT scans of the seven patients were compared to T2-weighted magnetic resonance image (MRI) scans of the brain to d etermine the correlation between functional and anatomical findings. I n six of the seven patients, the qualitative interpretation of the SPE CT studies supported the clinical findings (i.e., the visual field def ect) by revealing altered regional cerebral blood flow (rCBF) in the a ppropriate regions of the visual pathway. MR scans in all of the patie nts, on the other hand, were either normal or disclosed smaller lesion s than those detected by SPECT. We conclude that SPECT may reveal alte red rCBF in patients with cortical visual impairment of various etiolo gies, even when MRI studies are normal or nondiagnostic.