Atrophy rate in medial temporal lobe during progression of Alzheimer disease.

ABSTRACT

OBJECTIVE: To establish the progression of brain atrophy rates in patients with a known date of onset of Alzheimer disease (AD). METHODS: Each of 18 subjects had two high-resolution T1-weighted three-dimensional MRI examinations. The two MRIs were coregistered and the annual rate of brain tissue atrophy was derived both for the entire brain and regionally for the left and right medial temporal lobe (MTL). Time since onset (TSO) of AD, defined as the interval between the date of onset and the midpoint of MRI dates, ranged from -2.9 to 4.2 years. RESULTS: In patients with AD, TSO was a correlate of the atrophy rate for both the left MTL (R2 = 0.58, p = 0.001) and right MTL (R2 = 0.30, p = 0.03). When serial measurements were applied to a control group of 21 cognitively normal elderly subjects, MTL atrophy rate classified the group membership (AD vs normal cognition) with an accuracy of 92.3%. CONCLUSION: Increased annual atrophy rate in the medial temporal lobe is a potential diagnostic marker of the progression of Alzheimer disease.