[P2–415]: The Mayo Clinic Adult Lifespan Template: Better Quantification Across the Lifespan

The Mayo Clinic Study of Aging is an epidemiological study of human aging. Most MRI standard template spaces such as MNI152 are generated from scans of younger individuals. Because population-matched templates provide better quantitative MRI analysis, the goal of this work was to construct and make publically available a template for the analysis needs of aging and Alzheimer's Disease (AD) population studies. Subject Characteristics: This template was constructed from T1-weighted scans of 202 subjects including: 39 young clinically-normal subjects (age 30–49); 4 groups of 20 (each 10 men + 10 women) clinically normal subjects from each age range 50–59, 60–69, 70–79, 80–89; and 83 subjects with probable AD dementia. Input images were acquired using two 3T GE scanners (models 750, Signa Excite) with ADNI-1 MP-RAGE protocols and corrected for gradient distortion in 3D and nonuniformity using N3 and SPM5. SPM12b was used to segment these preprocessed images with stock priors, and these segmentations were validated by image analysts. DARTEL was used to produce new tissue priors and deformations from the input images to the new template space via groupwise registration. A T1-weighted template was produced by intensity-normalizing each scan, using the DARTEL warps to transform them to the common space, and averaging. Tissue priors were edited manually to reduce erroneous GM at WM/CSF borders, in the brainstem, and in the neck, and to create a more-defined fornix region in the WM priors. An AAL atlas was transformed to the template using ANTs nonlinear registration and manually edited to create accurate boundaries. A lobar atlas was also drawn manually. In preliminary work, we found that using the template with SPM12 provided improved segmentations, specifically in individuals with large ventricles and extensive brain atrophy. We created a template suitable for studies with a wide range of ages and disease states throughout the adult lifespan ages 30+. The template, tissue probability maps, and related atlases are being made publically available to the research community for non-commercial use. Future studies will elucidate the improvement in MRI quantitation in comparison to existing templates. The Mayo Clinic Adult Lifespan Template a) T1 -weighted image b) 122-region modified AAL atlas c) 14-region lobar atlas d) GM tissue probability mask e) WM tissue probability mask f) CSF tissue probability mask