Optimized Atlas for Early Tau-Pet Staging Via Native Space Segmentations

Abstract

Positron Emission Tomography (PET) early Braak staging might be susceptible to anatomical variability and reduced dimensions of medial temporal lobe (MTL) structures.  Optimized atlases should improve staging accuracy by accounting to size and anatomical variability. This study aimed to compare the accuracy of early tau detection using an optimized MTL segmentation. Six native space MTL structures were used as regions of interest (ROI) for [18F]MK6240 tau-PET images and compared with standard space Braak stage ROIs for 333 participants aged over 55. We used the Rey Auditory Verbal Learning Test (RAVLT) to assess memory. Native and standard space tau-PET stage ROIs were compared, then combined into an optimized MTL atlas. The optimized MTL atlas, informed by native space segmentations, identified more participants with an initial tau accumulation and found an earlier clinically relevant Braak stage III tau accumulation. Standard space approaches can be improved by studying smaller native space ROIs.

Note:
Funding declaration: PRN and the McGill University Research Centre for Studies in Aging receive support from the Weston Bain Institute, the Canadian Institutes of Health Research [MOP-11-51-31; RFN 152985, 159815, 162303], the Canadian Consortium of Neurodegeneration and Aging (CCNA; MOP-11-51-31 -team 1), the Alzheimer’s Association [NIRG-12-92090, NIRP-12-259245], the Brain Canada Foundation (CFI Project 34874; 33397), and the Fonds de Recherche du Québec – Santé (FRQS; Chercheur Boursier, 2020-VICO 279314). EA received funding from a FRQS postdoctoral training scholarship. PRN and SG are members of the CIHR-CCNA Canadian Consortium of Neurodegeneration in Aging. Colin J. Adair Charitable Foundation funded this project.

Conflict of Interests: The authors have no conflict of interest to disclose.

Keywords: Medial temporal lobe, Tau, PET imaging, Alzheimer's Disease, Automatic segmentation