17. CT scan in Alzheimer’s disease . Note the marked dilatation of the sulci and fissures, especially frontally, the poor visual distinction between grey matter and white matter, the ventricular enlargement – greater on the patient’s left (right of picture) and the general reduction in brain size. The picture is not diagnostic of Alzheimer’s disease: similar abnormalities occur in Huntington’s disease and Niemann-Pick’s disease.
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20. CT scan in multi-infarct dementia . The ventricles are normal in size, but there are patchy radiolucencies throughout the white matter. These indicate the presence of demyelinated patches, which result from multiple small infarcts in the brain.
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25. Hydrocephalus in an active 69-year-old man . This axial MRI at the level of the ventricular bodies shows severe ventricular enlargement, but the sulci of the brain are normal. The patient had communicating (normal pressure) hydrocephalus, associated with minimal memory impairment but no other significant abnormality. Many patients develop the clinical triad of dementia, ataxia, and incontinence.