3D comparison of low, intermediate, and advanced hippocampal atrophy in MCI

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Abstract
We applied the hippocampal radial atrophy mapping technique to the baseline and follow‐up magnetic resonance image data of 169 amnestic mild cognitive impairment (MCI) participants in the imaging arm of the Alzheimer's Disease Cooperative Study MCI Donepezil/Vitamin E trial. Sixty percent of the subjects with none to mild hippocampal atrophy rated with the visual medial temporal atrophy rating scale (MTA score < 2) and 33.8% of the subjects with moderate to severe (MTA ≥ 2) hippocampal atrophy converted to Alzheimer's disease (AD) during 3‐year follow‐up. MTA ≥ 2 showed a trend for greater left sided hippocampal atrophy versus MTA < 2 groups at baseline (Pcorrected = 0.08). Higher MTA scores were associated with progressive atrophy of the subiculum and the CA1‐3 subregions. The MTA < 2 group demonstrated significant bilateral atrophy progression at follow‐up (left Pcorrected = 0.008; right Pcorrected = 0.05). Relative to MTA < 2 nonconverters, MTA < 2 converters showed further involvement of the subiculum and CA1 and additional involvement of CA2‐3 at follow‐up. Right CA1 atrophy was significantly associated with conversion to dementia (for 1 mm greater right CA1 radial distance subjects had 50% reduced hazard for conversion). Greater CA1 and subicular atrophy can be demonstrated early and is predictive of future conversion to AD, whereas CA2‐3 involvement becomes more evident as the disease progresses. Hum Brain Mapp, 2010.