Highly Accelerated 1-mm Isotropic 3D Chemical Exchange Saturation Transfer MRI Using Wave-Co-CAIPI at 5 Tesla.

Abstract

Chemical exchange saturation transfer (CEST) is a powerful magnetic resonance imaging (MRI) technique for noninvasively probing both endogenous metabolites and exogenous contrast agents, with broad applications across various diseases. Although three-dimensional (3D) CEST MRI enables volumetric characterization of tissue heterogeneity, its clinical utility is hampered by long scan time because large volumetric datasets must be repeatedly acquired at multiple saturation frequency offsets. This limitation becomes more pronounced at high spatial resolutions. To address this challenge, we propose Wave-Co-CAIPI, a novel method that integrates Wave-CAIPI encoding with center-out reordering and keyhole sampling strategy, to substantially accelerate data acquisition for high-resolution 3D CEST MRI. Experiments conducted on in-vitro glutamate phantom and in-vivo human subjects at 5 Tesla demonstrate the feasibility and effectiveness of the method, achieving up to nine-fold k-space acceleration for 1 mm isotropic resolution in both amide proton transfer-weighted and glutamate-weighted 3D CEST imaging. These results highlight the potential of the proposed Wave-Co-CAIPI to enable highly accelerated, high-resolution 3D CEST MRI in clinical practice.