Mapping of SPECT regional cerebral perfusion abnormalities in obsessive‐compulsive disorder

Locations of cerebral perfusion abnormalities in obsessive‐compulsive disorder (OCD) were mapped with single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). This report is a new, more thorough analysis of a previous study of these subjects that used region‐of‐interest methods. Ten obsessive‐compulsive patients and seven age‐ and sex‐matched control subjects were studied. Image sets were converted into stereotaxic space, normalized to each subject's mean cerebral value, then group averaged. Difference images were calculated and searched for regions with significant between‐group cerebral perfusion differences. Obsessive‐compulsive patients had significantly higher relative cerebral perfusion in medial‐frontal and right frontal cortex and in cerebellum, and significantly reduced perfusion in right visual association cortex. Increased frontal Perfusion agrees with several prior reports. The caudate nucleus, which has been controversial in neuroimaging studies of OCD, did not display a difference between groups. The results of this study provide information about the locations and extents of cerebral perfusion abnormalities in OCD. Regional abnormalities were compared with those reported in prior functional neuroimaging studies. Issues related to OCD hyperfrontality and frontal lateralization of psychopathology are discussed. Normal caudate nucleus findings are considered in relation to prior functional imaging studies and hypotheses of OCD pathology. © 1994 Wiley‐Liss, Inc.