HMPAO-SPECT IN DEMENTIA OF THE ALZHEIMER- TYPE AND MAJOR DEPRESSION WITH MEMORY IMPAIRMENT

The aim of the present study was to see whether HMPAO-SPECT may contri bute to the differentiation between dementia of the Alzheimer type (DA T) and major depression (MD). The results in 77 patients with memory i mpairment were evaluated. 48 patients suffered from DAT and 29 from MD . Initially, the defects in SPECT imaging were attributed to a cerebra l region and the degree of decrease was evaluated (-1/-2/-3). Thereaft er, the results were classified by 7 categories. In some of these cate gories an accumulation of cases of either DAT or MD was found. 35% of the patients suffering from DAT had bilateral defects with distinct (> -1) parietal/parietotemporal hypoperfusions, but no patient with MD sh owed this perfusion pattern. 62% of the patients with MD had unilatera l defects but only 31% of the patients with DAT. The present study dem onstrates that only 35% of all patients suffering from DAT show a perf usion pattern, thought earlier as ''pathognomonic'' for this disease. This perfusion pattern - if it exists - may be used as a safe criterio n to exclude MD. Beyond that no clearcut (''specific'') perfusion patt ern may be recognized but unilateral defects point to MD.