[Cranial magnetic resonance tomography--value in diagnosis of dementia. Important additional information for differential diagnosis].

The clinical data and the magnetic resonance imaging (MRI) findings of 41 patients with clinically diagnosed dementia of the Alzheimer type (DAT) and 20 age-matched healthy controls were evaluated with the aim of determining the value of MRI in the diagnosis and differential diagnosis of dementia. Patients and controls with cerebrovascular risk factors, including a history of stroke, were excluded from the analysis. The MRI findings of patients with dementia revealed pathological changes, in particular cerebral atrophy (p < 0.0005), significantly more frequently than did those of controls (p < 0.005). Periventricular demyelinisation and lesions of the white matter were found in 23 (56%) patients, and in 6 (30%) of the controls. MRI revealed one case each of subdural hematoma, hydrocephalus and cerebral amyloid angiopathy. In 14 patients, the detection MRI scans of cerebral infarctions or hematomas suggested a major vascular component of the dementia. In contrast, lesions of the white matter can not reliably by ascribed to a vascular etiology. On the basis of our findings, it is concluded that cranial MRI is of great value for the differential diagnosis of dementia, even when the clinical diagnosis of Alzheimer's dementia is probable and cerebrovascular risk factors are absent.