Does computed tomographic brain imaging have a place in the diagnosis of dementia?
P. A. Engel and J. Gelber
Department of Medicine, New Britain General Hospital, CT.
BACKGROUND--Computed tomographic (CT) scanning of the head is an accepted
routine in the evaluation of dementia. This study attempted to identify a
patient group in which brain imaging adds meaningful data to the clinical
picture. METHODS--One hundred patients who met criteria for dementia as
defined in the Diagnostic and Statistical Manual of Mental Disorders,
Revised Third Edition, underwent computed tomographic imaging. From
clinical data alone, 56 of these patients also met the following strict
criteria for the diagnosis of probable Alzheimer's disease (PAD): the
McKhann criteria for PAD, Diagnostic and Statistical Manual of Mental
Disorders, Revised Third Edition, criteria for primary degenerative
dementia, a score of less than 4 on the modified Hachinski Ischemia Scale,
a normal neurologic examination and symptoms for at least 1 year.
RESULTS--In the PAD group, eight scans (14%) had abnormalities other than
atrophy; only three (two showing lacunae and one showing infarct) were of
possible clinical significance. In the 44 patients not meeting PAD
criteria, 23 scans (52%) were abnormal, including 15 with infarcts, two
with periventricular lucencies, three showing tumors, and one showing
hydrocephalus. CONCLUSIONS--These results support the diagnostic value of
computed tomographic scanning in atypical dementia and its limited utility
in PAD. The data indicate that clinical guidelines can be developed for the
application of CT in the diagnosis of dementia.
