The Diagnosis of Alzheimer-Type Dementia: A Preliminary Comparison of Positron Emission Tomography and Proton Magnetic Resonance

DESPITE recent advances in our understanding of the pathophysiology of Alzheimer's disease (AD), we remain unable to make the diagnosis noninvasively, except by exclusion. While computed tomography (CT) is of great value in indicating the absence of other dementing illnesses, it cannot be relied on to confirm the diagnosis of AD. The cortical and ventricular atrophy present in AD is not apparent in all cases and often cannot be distinguished from the changes on CT in healthy, aged persons. 1 The more recently developed technique of positron emission tomography (PET) has been used with a labeled glucose analogue ( 18 F)-2-fluoro-2-deoxy-D-glucose (FDG) to study glucose metabolism in dementia non-invasively. Specific regional alterations, particularly in the temporalparietal cortex, have been found. 2-5 Magnetic resonance (MR) imaging is another powerful new technology that is beginning to be applied to dementia. In this report we present a comparison of the findings in PET-FDG studies