Decreased cerebellar blood flow in postinfectious acute cerebellar ataxia.

OBJECTIVE The aim of the present study was to evaluate the regional cerebral blood flow (rCBF) in patients with postinfectious acute cerebellar ataxia using single photon emission computed tomography (SPECT). METHODS Five children with postinfectious acute cerebellar ataxia and five control subjects were examined. The distribution of rCBF was measured by SPECT imaging after intravenous administration of 123I-IMP (111 MBq). The rCBF ratio-defined as the ratio of rCBF in the region of interest (ROI) to that in the occipital cortex-was calculated for each cortical and subcortical ROI. The mean rCBF ratio of each region was then compared between the ataxic and control subjects. These patients and all control subjects were also evaluated using MRI. RESULTS The rCBF ratio was significantly lower in the cerebellum of the ataxic patients than in the cerebellum of the control subjects (p<0.05). No abnormal cerebellar morphology and no abnormal signal intensities were found on MRI. CONCLUSION 123I-IMP SPECT clearly demonstrated the decreased rCBF in the cerebellum of all patients with postinfectious acute cerebellar ataxia.