[Chronological changes in the vasculature and the cerebral blood flow of two patients with isolated angiitis of the central nervous system].

Isolated angiitis of the central nervous system (IAC) is an inflammatory, rare vasculopathy confined to the central nervous system, and the exact etiology has remained uncertain. We report serial changes in the vasculature and the mean cerebral blood flow (mCBF) in two patients with IAC. The first patient, a 58-year-old female, had sudden onset of severe headache and CT 4 days later showed cerebral hemorrhage in the frontal lobe. MRA revealed that the main trunks were dilated on admission, whereas two weeks later, diffuse narrowing of affected arteries occurred in multiple vascular distributions. She required about two months for almost full recovery in MRA findings. Mean CBF during the period of vascular narrowing did not correlate with the form of vasculature, and was much the same as that in the chronic phase. The second patient, a 24-year-old female, presented with severe headache one day after delivery following an uncomplicated pregnancy. MRA findings showed that, at first, segmental stenoses were located only in the peripheral regions of the middle cerebral artery, but this vascular abnormality spread to the anterior, middle and posterior cerebral arteries. She showed almost full recovery in MRA findings after about 3 months. SPECT analysis showed approximately 35% decrease in mCBF compared with that in the chronic phase. In the first case, hyperemia, which was caused by inflammatory cells infiltrating into the brain parenchyma through the vessel wall, contributed to cerebral hemorrhage. On the other hand, in the second case it was presumed that because inflammation was restricted to the vascular wall, mCBF consequently correlated with the form of vasculature. Our experience suggests that IAC has several etiologies.