Fluorodeoxyglucose Positron Emission Tomography Studies in Presumed Alzheimer Cases, Including 13 Serial Scans

Positron emission tomographic (PET) data on local cerebral metabolic rates for glucose (LCMR) are reported for 32 regions of interest (ROI)s in cross-sectional studies on 57 patients with clinically diagnosed Alzheimer's disease (AD) and 20 neurologically normal controls, and in serial studies on 13 of the AD cases, including a familial, young-onset case where the diagnosis has been confirmed at autopsy. Extensive psychological testing was done on all the AD cases. Almost all cortical regions showed a significant decline in LCMR with age in the control subjects. There were the expected cortical metabolic deficits in AD and the serial studies showed a general increase in such deficits over time in 12 of the 13 cases. The regions showing the greatest declines with time in serial studies are the same as those showing the most severe deficiencies in cross-sectional studies. The young-onset case did not show a greater rate of metabolic decline than many of the older cases studied. Results on individual psychological tests tended to correlate with metabolic rates in multiple, rather than single, cortical regions, suggesting intact neuronal networks are required for good performance. The correlations with cortical metabolic activity found were of a sign indicating that the higher the metabolic rates and the better the left:right asymmetry index, the better was the performance. RESUME: Tomographic par emission de positrons utilisant le F-fluorodeoxyglucose chez des cas presumement atteints de la maladie d'Alzheimer, dont 13 scans series Nous rapportons les donnces sur les taux m£taboliques cerebraux locaux d'utilisation du glucose (TMCL) determines au moyen de la tomographic par emission de positrons (PET) dans 32 regions d'interet, en etude transversale chez 57 patients avec un diagnostic clinique de maladie d'Alzheimer (MA) et 20 controles normaux au point de vue neurologique, en etude seriee chez 13 cas de MA, incluant un cas de MA familiale, a debut precoce, ou le diagnostic a ete confirme a l'autopsie. Tous les cas de MA ont &\€ soumis a une evaluation psychologique poussee. 11 existait une diminution significative du TMCL avec l'age chez les controles dans presque toutes les regions corticales. Les deficits metaboliques corticaux auxquels on s'attendait elaient presents dans la MA et les etudes seriees ont montre un accroissement general de ces deficits avec le temps chez 12 des 13 sujets. Les regions manifestant les plus hauts taux de progression des deficits avec le temps dans les efudes seYiees sont les memes que celles manifestant les deficits les plus seVeres dans les Etudes transversales. Le cas a d6but precoce ne montrait pas une diminution plus rapide du taux metabolique que plusieurs des cas plus ages qui ont efe Studies. Les resultats des epreuves psychologiques individuelles tendaient a etre en correlation avec les taux metaboliques dans plusieurs regions corticales plutot que dans une seule, suggerant que des reseaux neuronaux intacts sont requis pour fournir un bon rendement. Les correlations avec l'activite metabolique corticale indiquent que plus les taux metaboliques etaient eleves et meilleur etait l'index d'asymetrie gauche : droite, meilleur etait le rendement. Can. J. Neurol. Sci. 1990; 17:1-11 It is well established that patients with clinically diagnosed Alzheimer disease (AD) show decreased cortical metabolic rates in positron emission tomographic (PET) scans using F-fluorodeoxyglucose. Although the symptoms of AD are progressive, relatively few reports exist of serial PET scans on patients to document the course of the metabolic disorder and to determine whether relationships exist between psychological deficits and local cerebral metabolic rates for glucose (LCMR). This paper is an attempt to determine: (i) whether there is an increasing metabolic deficit with time which is more or less uniform from case to case or from region to region of brain; and (ii) if the LCMRs (or changes in LCMRs over time) correlate with results of psychological tests (or change in performance). We were particularly interested in whether relatively young AD cases would From the Kinsmen Laboratory of Neurological Research Department of Psychiatry (E.G.M., P.L.M., R.P., H.A.); Division of Neurology, Department of Medicine (R.P.P., D.B.C.); Department of Psychology, University Hospital (H.T.); Division of Psychology, Department of Psychiatry (D.C., R.P.); Department of Medicine, University of B.C. (B.L.B.), Vancouver, and School of Computer Science, Simon Fraser University (R.H.), Burnaby, British Columbia Received June 5, 1989. Accepted in final form September 30, 1989 Reprint requests to: Dr. Edith McGeer, 2255 Wesbrook Mall, University of B.C., Vancouver, British Columbia, Canada V6T 1W5