Quantitative computed tomography in senile dementia.

Mean computed tomography (CT) numbers or Hounsfield units (HU) were computed in 15 regions of the brain in routine CT scans of 25 patients with senile dementia and 29 normal community volunteer controls. Mean HU values were significantly lower bilaterally in the medial temporal lobe, anterior frontal lobe, and head of the caudate in the group of patients with senile dementia. There was no correlation between mean HU values and age, and covariate analysis showed that the differences between patients and controls were not attributable to the size of the ventricles. These data suggest that the determination of mean HU values from selected technically suitable regions of CT scans of the brain may have clinical applications of the diagnosis of senile dementia and provide a reliable means of monitoring changes in brain tissue density during the course of senile dementia.