[Usefulness of rCBF SPECT in patients with encephalitis: comparison study with MRI]

Twenty-nine rCBF SPECT study was done in 17 patients with encephalitis. Five of 6 patients (83.3%) showed regional high uptake in acute phase within a week after onset and 16 of 23 studies (69.6%) showed regional low uptake in subacute and chronic phase. Six of 19 lesions (31.6%) with regional high uptake changed to low uptake and 11 lesions (57.9%) improved to normal uptake on follow up studies. Seventeen of 51 lesions with low uptake (33.3%) improved to normal uptake. On the comparative study with MRI, 8 of 18 (44.4%) high uptake area showed cortical thickness or high intensity on T2 weighted images. Thirty-six of 74 low uptake area (48.6%) showed cortical thickness, brain atrophy or high intensity on T2 weighted images. Forty-eight of 212 regions (22.6%) with normal MRI findings showed abnormal accumulation of cerebral tracer on rCBF SPECT studies. rCBF SPECT was useful tool for diagnosis and follow up management in patients with encephalitis.