Changing ischaemic lesion patterns in adult moyamoya disease

Objectives: Ischaemic stroke is a frequent manifestation in patients with adult moyamoya disease (MMD), but the relationship between the lesion pattern and disease severity has rarely been investigated. Methods: Data were collected on a consecutive series of 65 adult patients with MMD who visited our hospital between 1999 and 2006. Among them, 32 patients with first ever ischaemic stroke were included. The ischaemic lesions were categorised by location and compared as follows: (1) cortical versus subcortical involvement and (2) anterior (fronto-temporal) versus posterior (parieto-occipital) involvement. The lesions were also compared by disease severity, as determined by the extent of intracranial artery involvement (Suzuki's grading method) and by perfusion status visualised on single photon emission computed tomography (SPECT). Result: Disease severity was significantly greater in patients with cortical involvement than in those with subcortical involvement (Suzuki's grade 4.17 (0.72) vs 2.70 (0.73); p<0.001). Disease severity was also significantly greater in patients with posterior involvement than in those with anterior involvement (4.50 (0.53) vs 2.83 (0.76); p<0.001). In most of the patients (83.3%) the perfusion defect area shown on SPECT was larger than the ischaemic lesion area shown on MRI. Conclusions: Patients with advanced stage adult MMD tended to have ischaemic lesions involving the cortex and posterior part of the brain and the stroke mechanism in these patients was largely associated with haemodynamic compromise. Our results suggest that the lesion pattern of ischaemic stroke may change along with the extent of arterial involvement.