Reduced perfusion in the anterior cingulate cortex of patients with pure autonomic failure: an 123I-IMP SPECT study

Background: Pure autonomic failure (PAF) is a selective peripheral disorder in which Lewy bodies form within the autonomic ganglia. Patients with this disorder usually have no central lesions; however, chronic autonomic failure may secondarily affect the central nervous system. This study evaluated brain perfusion in patients with PAF by using N-isopropyl-p-I-123 iodoamphetamine (I-123-IMP) single photon emission computed tomography (SPECT). Methods: Six patients with PAF (all men; mean (SD) age 68 +/- 5 years) who had experienced autonomic symptoms for more than 5 years and six age-matched healthy control subjects (all men; mean (SD) age 67 +/- 5 years) were included in this study. The regions of interest (ROI) on spacially normalized I-123-IMP SPECT images were automatically computed for both groups. Results: Perfusion of the dorsal anterior cingulate cortex was decreased in the PAF group compared with the healthy control group (0.93 vs 1.01; p<0.001). In the other brain regions measured, there was no significant difference in regional perfusion between the two groups. Conclusions: The dorsal anterior cingulate cortex is poorly perfused and may be functionally altered in patients with PAF. The reduced perfusion in such individuals may be a secondary change that results from chronic autonomic failure.