MR findings of eosinophilic meningoencephalitis attributed to Angiostrongylus cantonensis.

Eosinophilic meningoencephalitis is prevalent and widely distributed in Thailand, especially in the northeastern and central parts of the country. Angiostrongylus cantonensis is one of the causative agents of fatal eosinophilic meningoencephalitis. The nematodes produce extensive tissue damage by moving through the brain and inducing an inflammatory reaction. We report the clinical features and the findings revealed by MR imaging and MR spectroscopy in six patients with eosinophilic meningoencephalitis. The clinical presentation included severe headache, clouded consciousness, and meningeal irritation. Abnormal findings on MR images included prominence of the Virchow-Robin spaces, subcortical enhancing lesions, and abnormal high T2 signal lesions in the periventricular regions. Proton brain MR spectroscopy was performed in three patients and was abnormal in one severe case, showing decreased choline in a lesion. Small hemorrhagic tracts were found in one case. Lesions thought to be due to microcavities and migratory tracts were found in only one case. We believe the MR imaging and MR spectroscopy findings are of diagnostic value and helpful in understanding the pathogenetic mechanisms of the disease.