Progress in neuroimaging of Alzheimer's disease

• Published in: Psychogeriatrics 2007-09, Vol.7 (3), p.118-124
• Main Author: MATSUDA, Hiroshi
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; MRI; PET; SPECT
• ISSN: 1346-3500; 1479-8301
• DOI: 10.1111/j.1479-8301.2007.00175.x

The main purposes of neuroimaging in Alzheimer’s disease (AD) have progressed from diagnosis of advanced AD to diagnosis of very early AD at a prodromal stage of mild cognitive impairment (MCI), prediction of conversion from MCI to AD and differential diagnosis from other diseases causing dementia. Structural MRI studies and functional studies using FDG‐PET and brain perfusion SPECT are widely used in diagnosis of AD. Outstanding progress in the diagnostic accuracy of these neuroimaging modalities has been obtained using statistical analysis on a voxel‐by‐voxel basis after spatial normalization of individual scans to a standardized brain‐volume template instead of visual inspection or a conventional region of interest technique. In a very early stage of AD, this statistical approach revealed gray matter loss in medial temporal areas prominently in the entorhinal cortex and hypometabolism or hypoperfusion in the posterior cingulate cortex and precunei. These two findings might be related in view of anatomical knowledge that the regions are linked through the circuit of Papez. This statistical approach also offers a predictive value of conversion from MCI to AD and accurate evaluation of therapeutic effects on brain metabolism or perfusion. This development in functional and structural imaging might be an important surrogate marker for trials of disease‐modifying agents.