Coexistent neurocysticercosis and Japanese B encephalitis: MR imaging correlation

BACKGROUND AND PURPOSE: An increased incidence of intestinal helminthic inf ections has been observed in patients with viral encephalitis in endemic ar eas. Both Japanese B encephalitis (JE) and neurocysticercosis (NCC) share s ome common socio-demographic and ecologic factors, and pigs act as the inte rmediate carrier for both. Our purpose was to show the coexistence of JE an d NCC in brain on MR images and highlight the possible role of NCC as an am plifier of JE. METHODS: MR images from 10 cases of coexistent JE and NCC were studied retr ospectively. T1-weighted axial and sagittal, proton T2-weighted axial and c oronal, and T2-weighted fluid-attenuated inversion recovery axial and coron al sections of the brain were evaluated. NCC was diagnosed on the basis of neuroimaging. Diagnostic serologic testing for JE was conducted using paire d blood and CSF samples. RESULTS: The JE changes were bilateral and asymmetrical and were more sever e on the side harboring the solitary cyst or the side bearing the greater n umber of cysts or lodging the degenerating cyst. In each of nine of 10 case s, at least one degenerating cyst was found on the side of predominant JE p athologic abnormality. CONCLUSION: The study suggests that the co-occurrence of JE and NCC is not just a chance coincidence. NCC apparently predisposes a person to JE infect ion and is a positive modulator of the encephalitic process. The study show s a spectrum of MR imaging findings of coexistent JE and NCC.