title: High-Dimensional Medial Lobe Morphometry: An Automated MRI Biomarker for the New AD Diagnostic Criteria.
abstract: Introduction. Medial temporal lobe atrophy assessment via magnetic resonance imaging (MRI) has been proposed in recent criteria as an in vivo diagnostic biomarker of Alzheimer's disease (AD). However, practical application of these criteria in a clinical setting will require automated MRI analysis techniques. To this end, we wished to validate our automated, high-dimensional morphometry technique to the hypothetical prediction of future clinical status from baseline data in a cohort of subjects in a large, multicentric setting, compared to currently known clinical status for these subjects. Materials and Methods. The study group consisted of 214 controls, 371 mild cognitive impairment (147 having progressed to probable AD and 224 stable), and 181 probable AD from the Alzheimer's Disease Neuroimaging Initiative, with data acquired on 58 different 1.5 T scanners. We measured the sensitivity and specificity of our technique in a hierarchical fashion, first testing the effect of intensity standardization, then between different volumes of interest, and finally its generalizability for a large, multicentric cohort. Results. We obtained 73.2% prediction accuracy with 79.5% sensitivity for the prediction of MCI progression to clinically probable AD. The positive predictive value was 81.6% for MCI progressing on average within 1.5 (0.3 s.d.) year. Conclusion. With high accuracy, the technique's ability to identify discriminant medial temporal lobe atrophy has been demonstrated in a large, multicentric environment. It is suitable as an aid for clinical diagnostic of AD.
authors.affiliation: Départment de Radiologie, Faculté de Médecine, Université Laval, Quebec, QC, Canada G1V 0A6 ; Institut Universitaire de Santé Mentale de Québec, 2601 de la Canardiére/F-3582, Quebec, QC, Canada G1J 2G3.
authors.forename: Simon
authors.identifier: 0000-0002-6326-0745
authors.initials: S
authors.lastname: Duchesne
authors.affiliation: Institut Universitaire de Santé Mentale de Québec, 2601 de la Canardiére/F-3582, Quebec, QC, Canada G1J 2G3.
authors.forename: Fernando
authors.initials: F
authors.lastname: Valdivia
authors.affiliation: Institut Universitaire de Santé Mentale de Québec, 2601 de la Canardiére/F-3582, Quebec, QC, Canada G1J 2G3.
authors.forename: Abderazzak
authors.identifier: 0000-0001-6989-4688
authors.initials: A
authors.lastname: Mouiha
authors.affiliation: Institut Universitaire de Santé Mentale de Québec, 2601 de la Canardiére/F-3582, Quebec, QC, Canada G1J 2G3.
authors.forename: Nicolas
authors.identifier: 0000-0003-1908-573X
authors.initials: N
authors.lastname: Robitaille