INTRODUCTION Alzheimer disease is related to several risk factors including aging, family history, high blood pressure and diabetes. Studies have shown specific regional cerebral perfusion changes in patients with Alzheimer disease. Some authors state that these changes could appear years before patient memory becomes impaired, enabling early diagnosis in high-risk persons who appear to be healthy.

OBJECTIVE Determine the usefulness of cerebral perfusion studies in Alzheimer patients and first-degree relatives for obtaining additional diagnostic information and detecting functional changes that may suggest elevated disease risk.

METHODS This study involved 128 persons (87 clinically diagnosed with Alzheimer disease and 41 of their first-degree relatives with normal cognition), all from Artemisa Province, Cuba. We performed clinical, laboratory, neuropsychological and genetic (apolipoprotein E—ApoE, e4 allele) tests, as well as cerebral perfusion studies using single photon emission computed tomography after administering 740–925 MBq of 99m Tc-ECD, following internationally standardized protocols.

RESULTS In the Alzheimer disease group, the cerebral single photon emission computed tomography showed a typical Alzheimer pattern (bilateral posterior temporal-parietal hypoperfusion) in 77% (67/87) of participants; 35.9% (28/67) in stage 1; 51.3% (40/67) in stage 2; and 12.8% (10/67) in stage 3 of the disease. In this group, 12.7% (11/87) had mild or unilateral cerebral perfusion changes; 5.7% (5/87) vascular dementia; 3.4% (3/87) frontal dementia; and 1.2% (1/87) normal cerebral perfusion. Of the patients, 28.7% (25/87) received a different classification of stage and disease diagnosis after cerebral perfusion results were considered. In the relative group, 14.6% (6/41) had cerebral perfusion abnormalities. Among these, 7.1% (3/41) were mild bilateral temporal–parietal hypoperfusion; 4.8% (2/41) mild unilateral temporal–parietal hypoperfusion; and 2.4% (1/41) had perfusion defecits in their right frontal lobes. Of patients with typical Alzheimer disease patterns in the cerebral single photon emission computed tomography, 76.6% (52/67) had positive ApoE e4. All relatives with perfusion abnormalities (6/6) had positive ApoE e4.

CONCLUSIONS Cerebral perfusion studies confirmed the Alzheimer disease diagnosis, classified disease stages, and differentiated between the types of dementia. The test showed perfusion changes in several asymptomatic first-degree relatives with positive ApoE e4, which could be predictors of disease. The technique was useful for evaluating patients and their relatives.

KEYWORDS Cerebrovascular circulation; tomography, emission-computed, single-photon; Alzheimer disease; Alzheimer’s disease; Cuba