Accelerated 3D MRI for ARIA monitoring in Alzheimer's disease

Amyloid-targeting therapies for Alzheimer's disease require regular MRI monitoring for amyloid-related imaging abnormalities (ARIA). 3D scans are more sensitive but time intensive; ultra-fast implementations could improve access and reduce burden.

Eighty scans from 20 participants were acquired with standard 2D fluid-attenuated inversion recovery (FLAIR) and T2*-gradient recalled echo (T2*-GRE), or accelerated Wave-controlled aliasing in parallel imaging (Wave-CAIPI) 3D FLAIR and susceptibility-weighted imaging (SWI) at 3 T. Two neuroradiologists graded ARIA-E (edema/effusion) and ARIA-H (hemosiderin deposits). Bayesian models estimated sensitivity, specificity, severity agreement, and interchangeability between acquisitions.

Accelerated sequences reduced acquisition time by up to 56%. Four participants had ARIA-E and microbleeds; five had microbleeds alone. Sensitivity and specificity for ARIA-E were identical (1.00; 0.94-0.95); severity was comparable. Replacing standard with accelerated FLAIR did not decrease severity agreement (interchangeability 1.4; 95% highest-density interval [HDI] -3.6% to 5.4%). Fast SWI showed higher microbleed severity gradings.

Wave-CAIPI offers fast high-resolution FLAIR acquisitions with comparable performance for ARIA-E monitoring. Wave-CAIPI SWI provides high-quality scans that may aid ARIA-H interpretation.