AUTHOR=Gullett Joseph M. , Albizu Alejandro , Fang Ruogu , Loewenstein David A. , Duara Ranjan , Rosselli Monica , Armstrong Melissa J. , Rundek Tatjana , Hausman Hanna K. , Dekosky Steven T. , Woods Adam J. , Cohen Ronald A. 

TITLE=Baseline Neuroimaging Predicts Decline to Dementia From Amnestic Mild Cognitive Impairment

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=13

YEAR=2021

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.758298

DOI=10.3389/fnagi.2021.758298

ISSN=1663-4365

ABSTRACT=<p><bold>Background and Objectives:</bold> Prediction of decline to dementia using objective biomarkers in high-risk patients with amnestic mild cognitive impairment (aMCI) has immense utility. Our objective was to use multimodal MRI to (1) determine whether accurate and precise prediction of dementia conversion could be achieved using baseline data alone, and (2) generate a map of the brain regions implicated in longitudinal decline to dementia.</p><p><bold>Methods:</bold> Participants meeting criteria for aMCI at baseline (<italic>N</italic> = 55) were classified at follow-up as remaining stable/improved in their diagnosis (<italic>N</italic> = 41) or declined to dementia (<italic>N</italic> = 14). Baseline T1 structural MRI and resting-state fMRI (rsfMRI) were combined and a semi-supervised support vector machine (SVM) which separated stable participants from those who decline at follow-up with maximal margin. Cross-validated model performance metrics and MRI feature weights were calculated to include the strength of each brain voxel in its ability to distinguish the two groups.</p><p><bold>Results:</bold> Total model accuracy for predicting diagnostic change at follow-up was 92.7% using baseline T1 imaging alone, 83.5% using rsfMRI alone, and 94.5% when combining T1 and rsfMRI modalities. Feature weights that survived the <italic>p</italic> &lt; 0.01 threshold for separation of the two groups revealed the strongest margin in the combined structural and functional regions underlying the medial temporal lobes in the limbic system.</p><p><bold>Discussion:</bold> An MRI-driven SVM model demonstrates accurate and precise prediction of later dementia conversion in aMCI patients. The multi-modal regions driving this prediction were the strongest in the medial temporal regions of the limbic system, consistent with literature on the progression of Alzheimer’s disease.</p>