Abstract
After a short historical note on the diversion of the vascular concept of dementia from that of primary degeneration, this review describes cerebral deterioration on vascular grounds in three levels. Occlusions of big vessels with a single major infarct, middle calibre vasculopathy with multiple lacunes and finally microangiopathy causing leukoaraiosis-all these three entities produce cognitive disorders.
Changes in the vessel wall, in cerebral blood flow velocity, the territorial and inter-territorial rules for the location of malacia or lacunes are reviewed using neuroradiologic aspects revealed by ultrasound, by CT and MRI. Alterations in diffusion and their measurements by MRI are discussed in regard to ultrastructural reactions to ischaemia.
Thresholds for tissue deterioration are shown in association with ATP depletion and with pathologic compounds in the interstitium.