Postinfectious cerebellitis: clinical significance of Tc-99m HMPAO brain SPECT compared with MRI.

PURPOSE We compared Tc-99m HMPAO brain SPECT and MRI with the clinical findings in a case of a 14-year-old boy with post-infectious cerebellitis. RESULTS Tc-99m HMPAO brain SPECT scan showed marked reduction in perfusion to the left anterior lobe, left lateral hemisphere, and left posterior lobe of the cerebellum. The MRI showed a limited region of abnormal signal in the mid posterior left cerebellar hemisphere. Since the patient's overall neurological deficit was characterized by ataxia, nystagmus, head and body titubation, dysmetria, dysdiadochokinesia, loss of normal check, and rebound testing attributed to the involvement of the anterior, lateral, and posterior lobes of the left cerebellar hemisphere, the Tc-99m HMPAO brain SPECT finding correlated better with the extent of functional neurological deficits. CONCLUSION Tc-99m HMPAO brain SPECT may better assess cerebellar signs and symptoms in cerebellitis since the blood flow abnormalities correlated with dysfunction of the cerebellum, whereas the MRI abnormalities did not encompass the scope of the neurological deficits.