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Imaging plays an increasingly important role in both clinical practice and research in Alzheimer's disease. Clinically, there is growing appreciation that imaging provides not just exclusion of alternative pathologies, but also positive predictive, diagnostic, and prognostic information in dementia. Imaging can improve specificity of diagnosis in trial populations, facilitate research on the earlier stages of disease, and provide crucial information regarding drug safety and toxicity. With the advent of disease-modifying therapies, these properties acquire increasing importance. Furthermore, imaging biomarkers have the potential to serve as outcome measures of disease progression. A whole arsenal of imaging modalities has now been developed, each allowing a different aspect of the disease process to be explored. However, the limitations of each technique must also be appreciated. A multimodal approach, where imaging markers are combined, may be required to maximize the potential of imaging to enhance our understanding of Alzheimer's disease and to help find effective therapies. [ABSTRACT FROM AUTHOR]

Abstract: Medial temporal lobe atrophy (MTA) is a recognized marker of Alzheimer''s disease (AD), however, it can be prominent in frontotemporal lobar degeneration (FTLD). There is an increasing awareness that posterior atrophy (PA) is important in AD and may aid the differentiation of AD from FTLD. Visual rating scales are a convenient way of assessing atrophy in a clinical setting. In this study, 2 visual rating scales measuring MTA and PA were used to compare atrophy patterns in 62 pathologically-confirmed AD and 40 FTLD patients. Anatomical correspondence of MTA and PA was assessed using manually-delineated regions of the hippocampus and posterior cingulate gyrus, respectively. Both MTA and PA scales showed good inter- and intrarater reliabilities (kappa > 0.8). MTA scores showed a good correspondence with manual hippocampal volumes. Thirty percent of the AD patients showed PA in the absence of MTA. Adding the PA to the MTA scale improved discrimination of AD from FTLD, and early-onset AD from normal aging. These results underline the importance of considering PA in AD diagnosis, particularly in younger patients where medial temporal atrophy may be less conspicuous. [Copyright &y& Elsevier]