Magnetic resonance imaging (MRI) and CT-scan are crucial for the diagnosis of cerebrovascular diseases. Multi-infarct dementias may be divided into (i) dementias due to multiple cortical infarcts and (ii) dementias due to multiple lacunar infarcts in the basal ganglia, thalamus and hemispheric white matter, usually associated with leukoaraiosis. A single infarct located in the thalamus or in the left angular gyrus may also induce dementia. Abnormalities of the cerebral white matter, so-called leukoaraiosis, are usually the consequence of a cerebrovascular disease and may be called Binswanger's disease in severe cases. However, leukoaraiosis is not specific of vascular dementia and may also be found in Alzheimer's disease and even in normal aging.