American Journal of Neuroradiology 2009;30:532.
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American Journal of Neuroradiology
DOI 10.3174/ajnr.A1397
BRAIN
Temporoparietal MR Imaging Measures of Atrophy in Subjects with Mild Cognitive Impairment That Predict Subsequent Diagnosis of Alzheimer Disease
From the Department of Anatomy and Neurobiology (R.S.D., R.J.K.), Boston University School of Medicine, Boston, Mass; Departments of Biostatistics (H.J.C.) and Environmental Health (R.J.K.), Boston University School of Public Health, Boston, Mass; Departments of Radiology (B.F.), Athinoula A. Martinos Center for Biomedical Imaging, Psychiatry (D.B., R.J.K.), and Neurology (B.T.H.), Massachusetts General Hospital, Boston, Mass; Computer Science and Artificial Intelligence Laboratory (B.F.), Massachusetts Institute of Technology, Cambridge, Mass; Department of Radiology (C.R.G.G., R.J.K.), Brigham and Women's Hospital, Boston, Mass; and Department of Neurology (M.S.A.), Johns Hopkins University School of Medicine, Baltimore, Md.
Please address correspondence to Ronald J. Killiany, PhD, Department of Anatomy and Neurobiology, Center of Biomedical Imaging, Boston University School of Medicine, 700 Albany St, W701, Boston, MA 02118; e-mail: killiany{at}bu.edu
BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) represents a transitional state between normal aging and Alzheimer disease (AD). Our goal was to determine if specific temporoparietal regions can predict the time to progress from MCI to AD.
MATERIALS AND METHODS: MR images from 129 individuals with MCI were analyzed to identify the volume of 14 neocortical and 2 non-neocortical brain regions, comprising the temporal and parietal lobes. In addition, 3 neuropsychological test scores were included to determine whether they would provide independent information. After a mean follow-up time of 5 years, 44 of these individuals had progressed to a diagnosis of AD.
RESULTS: Cox proportional hazards models demonstrated significant effects for 6 MR imaging regions with the greatest differences being the following: the entorhinal cortex (hazard ratio [HR] = 0.54, P < .001), inferior parietal lobule (hazard ratio [HR] = 0.64, P < .005), and middle temporal gyrus (HR = 0.64, P < .004), indicating decreased risk with larger volumes. A multivariable model showed that a combination of the entorhinal cortex (HR = 0.60, P < .001) and the inferior parietal lobule (HR = 0.62, P < .01) was the best predictor of time to progress to AD. A multivariable model reiterated the importance of including both MR imaging and neuropsychological variables in the final model.
CONCLUSIONS: These findings reaffirm the importance of the entorhinal cortex and present evidence for the importance of the inferior parietal lobule as a predictor of time to progress from MCI to AD. The inclusion of neuropsychological performance in the final model continues to highlight the importance of using these measures in a complementary fashion.