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

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-(123)I iodoamphetamine ((123)I-IMP) single photon emission computed tomography (SPECT).

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 (123)I-IMP SPECT images were automatically computed for both groups.

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.

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.