[Diagnosis of silent cerebral infarction].

High intensity lesions are frequently encountered in the basal ganglia, thalamus and cerebral white matter in T2-weighted images of MRI. Most of them are generally assumed to represent cerebral infarction without pathologic verification. Studies were performed on the brain showing such lesions with particular emphasis on the differential diagnosis of lacunar infarcts and dilated perivascular spaces. As a result, it was shown that irregularly shaped, lesions or those in the thalamus more frequently represent lacunar infarcts, while those with smooth rims or in the putamen likely represent dilated perivascular spaces. Neither proton density nor the size of the lesions on the MRI helps to differentiate the two conditions. Small patchy high intensity areas of the white matter in the T2-weighted images showed myelin pallor with mild gliosis. Periventricular "rims" of high intensity revealed only subependymal gliosis.