Regional cerebral blood flow scintigraphy in tick-borne encephalitis and other aseptic meningoencephalitis

In a prospective study, regional cerebral blood flow (rCBF) was studied in patients with aseptic meningoencephalitis at 6 wk and 1 yr after onset of d isease. Methods: Patients with tick-borne encephalitis ([TBE] n = 73) and m eningoencephalitis of other etiology ([non-TBE] n = 56) were investigated w ith rCBF-scintigraphy (SPECT). SPECT images in the acute phase of disease a nd at long-term follow-up were analyzed for blood-flow disturbances and the ir localization in the central nervous system and were correlated to clinic al course and outcome. Results: Decreased rCBF was seen in 50% of patients after 6 wk (TBE 49%, non-TEE 50%) and in 46% (TBE 47%, non-TEE 46%) after 1 yr. The decrease in rCBF was moderate in 18% and 11% at 6 wk and in 8% and 9% at the I-yr follow-up of TEE and non-TEE patients, respectively. Reduce d rCBF was significantly more common among patients with encephalitis than among those with meningitis, and more common in males. The distribution of cerebral flow changes was predominantly patchy or multifocal. At long-term follow-up, improvement in rCBF was seen in 28 of 109 patients (26%), but wo rsening of decreased rCBF was demonstrated in 19 of 109 (17%). In TEE patie nts, remaining neurological symptoms at 6 wk of disease were associated wit h worsening of decreased rCBF at the I-yr follow-up. Conclusion: With SPECT , rCBF changes, mostly slight and patchy or multifocal, were detected in pa tients with aseptic meningoencephalitis. Decreased rCBF was more frequent i n patients with moderate-to-severe encephalitis, although the clinical use in predicting long-term outcomes in aseptic meningoencephalitis (e.g., TEE) seems limited.