Quantitative computed tomographic analysis in the diagnosis of dementia.

We compared the computed tomographic (CT) scans of 46 patients with dementia with those of 46 normal subjects matched for age and sex. We measured the areas subtended by the third ventricle, frontal horns, bodies of the lateral ventricles, and interhemispheric fissure as depicted in CT sections, then determined the ratio between each of those areas and the entire brain at each level. Patients with dementia had significantly larger ratios on all measures. A multivariate classification procedure showed that a composite formula of two measures, the bodies of the lateral ventricles and the interhemispheric fissure, predicted clinical status in 84% of the cases. Findings indicated that some CT measurements reflected cerebral changes associated with dementia. If appreciated in a suitable probabilistic framework, these data may be clinically useful in supporting or weakening the diagnostic hypothesis of dementia in the many cases in which diagnosis is unclear.