Failure of CT scan to detect ischemic lesions in patients with dementia

Although clinical series have described relatively high accuracy in the ability of computed tomographic (CT) scan to detect significant cerebrovascular damage in patients with dementia, a recent neuropathologically controlled study failed to document that relationship. We now present clinical, neuroradiologic (CT), and neuropathologic information on four patients in whom CT scans did not contribute to the diagnosis of multi-infarct dementia or mixed dementia, despite clinical and neuropathologic evidence of infarcts. In one patient, the failure of CT scan to detect ischemic lesions may be attributable to less sensitive neuroradiologic criteria in use at the time of the examination. In the other three, even neuroradiologic review after the pathology was known failed to reveal the infarcts. These observations suggest the advisability of caution in using CT scan as a criterion for the presence or absence of cerebrovascular damage in patients with dementia.