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Optimized atlas for early tau-PET staging via native space segmentations
Etienne Aumont1, Brandon J Hall1, Tevy Chan1
1McGill University Research Centre for Studies in Aging, McGill University, Montréal, QC H4H 1R3, Canada; Montreal Neurological Institute, McGill University, Montréal, QC H3A 2B4, Canada; Department of neurology and neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada.
Optimizing Positron Emission Tomography (PET) staging with native space medial temporal lobe (MTL) segmentations improves early detection of tau pathology. This enhanced approach reveals more advanced Alzheimer's disease stages and associated memory deficits.
Area of Science:
- Neuroimaging
- Neuropathology
- Alzheimer's Disease Research
Background:
- Standard space Positron Emission Tomography (PET) staging for early Braak staging can be inaccurate due to medial temporal lobe (MTL) anatomical variability and atrophy.
- Improved staging accuracy requires accounting for individual anatomical differences in atlas-based analyses.
- Early detection of tau accumulation is crucial for understanding Alzheimer's disease (AD) progression.
Purpose of the Study:
- To compare the accuracy of early tau detection using traditional standard space methods versus native space MTL segmentations in [18F]MK6240 tau-PET imaging.
- To develop an optimized standard space MTL atlas that incorporates native space findings to improve staging accuracy.
- To assess the relationship between advanced tau pathology identified by native space staging and cognitive function, specifically memory.
Main Methods:
- Analyzed [18F]MK6240 tau-PET images from 333 participants over 55 years old.
- Utilized twelve native space MTL structures as regions of interest (ROIs) and compared them with standard space Braak stage ROIs.
- Assessed memory function using the Rey Auditory Verbal Learning Test (RAVLT).
- Developed an optimized standard space MTL atlas by combining native and standard space tau-PET data with anatomical constraints, determining optimal spatial smoothing (6 mm FWHM).
Main Results:
- Native space MTL tau-PET staging identified 34 participants with more advanced tau accumulation than standard space methods.
- Specifically, 14 participants showed significant entorhinal/transentorhinal tau despite being classified as Braak stage I (pre-I stage).
- Nineteen participants were classified as Braak stage III using native space methods (pre-III stage) versus Braak stage II using standard space methods; these pre-III participants exhibited significant memory impairment.
- The optimized standard space atlas, using 6 mm FWHM smoothing, successfully identified 29 of these 33 more advanced cases.
Conclusions:
- Native space MTL segmentations provide more accurate early detection of tau pathology compared to traditional standard space methods.
- An optimized standard space atlas can effectively replicate native space findings, improving sensitivity to early AD tau pathology.
- Improved tau-PET staging is more sensitive to cognitive impairment, highlighting the clinical relevance of accounting for individual anatomy in AD research.
