[Clinical study on the relationship between middle cerebral artery lesions and Binswanger type infarction]

To investigate the relationship between middle cerebral artery (MCA) trunk lesions and the etiology of Binswanger type (B type) infarction, which was demonstrated as a diffuse subcortical low density area/high intensity area by CT/MRI, patients with both MCA lesions and B type infarction were studied clinically. Eighteen patients with B type infarction were diagnosed among 224 patients with MCA occlusion/stenosis on angiography accounting for 8%. The incidence was as high as 25% in M2 stenosis. The mean age of B type infarction patients was 64 years and 16 of them were men. Chronologically stepwize/slowly-progressive deterioration of clinical manifestations were observed in 14. All patients had hemiplegia, though half of them were mild or moderate in severity. Furthermore, aphasia, Gerstmann syndrome and dementia were present in 10, 1 and 2 patients, respectively. Twelve had a history of hypertension, while 11 showed transient decreases with marked changes (more than 31 mmHg in mean arterial blood pressure) in arterial blood pressure during their clinical course. Out of 9 patients in whom cerebral blood flow (CBF) was measured by 133Xe injection method/inhalation method, 7 demonstrated mild to moderate decreases in mean CBF (more than 30 ml/100 g/min) with no relation to the severity of MCA lesions. These findings suggested that hemodynamic mechanisms associated with hypoperfusion due to marked fluctuations in blood pressure are accelerating factors of B type infarction and MCA lesions, even though ischemia in the subcortical area due to leptomeningeal anastomosis may be mild or moderate.