[Serial magnetic resonance angiography in a case with isolated angiitis of the CNS].

Isolated angiitis of the central nervous system (IAC) is an idiopathic type of vasculitis, exclusively affecting small to medium-sized blood vessels of the central nervous system. We report serial angiographical findings, mainly demonstrated with magnetic resonance angiography (MRA) in a case of IAC. A 58-year-old-female came to our hospital because of a sudden headache. Computed tomography (CT) did not show any particular findings. MRA 3 days after the onset revealed diffuse arterial dilatations and segmental stenoses of the middle and anterior cerebral arteries. However, these findings did not lead us to make a diagnosis of IAC. Two days later she was admitted with increased headache and subcortical hemorrhage in the left frontal lobe on CT. Subsequent MRA demonstrated remarkable changes such as dilatated main trunks with segmental stenoses. Steroid pulse therapy was started after definite diagnosis of IAC. She improved gradually and was headache-free 15 days after the onset. Nevertheless, follow-up MRA at 15 days revealed diffusely narrowed anterior and middle cerebral arteries with multiple segmental stenoses. Characteristic findings of angiitis showed improvement at 29 days and had disappeared at 73 days. The patient discontinued corticosteroids and has remained free from headache for the last 7 months.

[A case of brainstem encephalitis diagnosed by stereotactic biopsy].

Brainstem encephalitis is a rare form of encephalitis which should be differentiated from cerebrovascular and neoplastic diseases. The authors report a case of viral brainstem encephalitis mimicking malignant lymphoma. A 55-year-old female was admitted to our hospital with gradually progressive diplopia and left hemiplegia. CT scan revealed low density lesions in the right globus pallidus and the anterior limb of the internal capsule. MRI demonstrated high intensity signals extending into the right cerebral peduncle, temporal lobe, thalamus and the contralateral thalamus on FLAIR images. Petechial hemorrhages were seen in the affected lesions, but no enhancement was observed following administration of a contrast material. CSF examination revealed mild mononuclear cell dominant pleocytosis. Both early and delayed images of 123I-IMP SPECT revealed marked hot spots corresponding to the lesions on FLAIR images. CT-guided stereotactic biopsy was useful for early diagnosis.