[Computed cranial tomography, magnetic resonance imaging and brain echo imaging in Japanese B encephalitis]

We reported computed cranial tomography (CCT), magnetic resonance imaging (MRI) and brain echo imaging in Japanese B encephalitis. The result were assessed in comparison with the clinical feature of the disease. CCT of the three patients showed low density in thalamus and basal ganglia. In two, the lesions were detected in the acute phase, and changed to high density in the chronic phase. Their prognosis was poor, psychomotor delay and paresis persisted. Among the previously reported sixteen patients of Japanese B encephalitis in Japan, the four developed thalamic lesions on CCT and the prognosis was poor in all patients. Brain echo detected the lesions in the acute phase before CCT visualised them clearly. MRI demonstrated thalamic hemosiderin deposits and calcification. These findings were compatible with the pathological findings, or past hemorrhage and organization. The distribution of the lesion were closely connected with the prognosis.