Temporoparietal MRI Measures of Atrophy in Subjects with Mild Cognitive Impairment that Predict Subsequent Diagnosis of Alzheimer’s Disease

Background and Purpose—Mild cognitive impairment (MCI) represents a transitional state between normal aging and Alzheimer’s disease (AD). Our goal was to determine if specific temporoparietal regions can predict the time to progress from MCI to AD. Methods—MRI scans 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, three 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 six MRI regions with the greatest differences being: entorhinal cortex (HR=0.54, p < 0.001), inferior parietal lobule (HR=0.64, p <0.005), and middle temporal gyrus (HR=0.64, p < 0.004), indicating decreased risk with larger volumes. A multivariable model showed that a combination of the entorhinal cortex (HR = 0.60, p < 0.001) and inferior parietal lobule (HR = 0.62, p < 0.01) was the ‘best ’ predictor of time to progress to AD. A multivariable model re-iterated the importance of included both MRI an