A clinicopathological study of CT scans in Alzheimer's disease

To investigate the accuracy of cranial computerized tomography (CT) scans in distinguishing patients with Alzheimer's disease from those with other dementing conditions.

Retrospective clinicopathological correlation with pre-mortem CT scans.

Urban and rural hospitals and nursing homes in the Upper Midwest.

All 507 patients had clinical dementia diagnosed as Alzheimer's disease during life and the subsequent referral of their brains to a dementia brain bank. Of these, 375 patients had had CT scans as part of the diagnostic work-up for dementia.

The presence of neuropathological evidence of Alzheimer's disease and the specific findings on CT scans.

Of the 375 patients evaluated with a CT, 28% were misdiagnosed (lacked neuropathological evidence of Alzheimer's disease); of the 132 patients evaluated without a CT scan, only 18% were misdiagnosed (P less than 0.05). The degree of atrophy and other CT findings were similar in the correctly diagnosed and misdiagnosed groups except for increased ventricular size in the correctly diagnosed patients (P less than 0.05).

Although CT scans do not usually contribute to the recognition of Alzheimer's disease, the presence of ventricular enlargement may help distinguish Alzheimer's disease from other dementias.