We sought to determine whether single-photon-emission computed tomography (SPECT) of the brain is useful for detecting abnormalities of regional cerebral blood flow in patients with cerebral lupus. Twenty lupus patients with clinical evidence of cerebral involvement underwent SPECT and CT scanning of the brain, as well as clinical, expert neurologic, and serologic evaluation. Fifteen patients (75%) had a clear regional cerebral hypoperfusion. Seven of 8 patients (88%) who were ultimately thought to have active cerebral lupus had abnormal SPECT scan findings, while 8 of 12 patients (67%) who were ultimately thought not to have active cerebral lupus had abnormal SPECT scan findings. There was no correlation of SPECT findings with CT scan results, overall disease activity, or serologic findings. Regional cerebral blood flow measured by SPECT is often abnormal in patients with active cerebral lupus, but is also frequently abnormal in lupus patients with neuropsychiatric symptoms not attributable to cerebral lupus activity.