CEST fluid artifact identification by steady-state signal fitting (FISS)

Motivation: The fluid compartment may show as hyperintense or hypointense artifacts on post-processed CEST images. Goal(s): To propose a method identifying the fluid compartment on CEST images for improved image reading and quantitative analysis. Approach: The z-spectrum between -1 and 1 ppm is fitted to a steady-state signal model. The B1, fitted parameters, and fitting residue are used as features to differentiate fluid and tissue compartments. Results: The proposed method shows excellent performance for identifying fluid, with an AUC of 1. The post-processed CEST image masked by the fluid mask has improved readability. Impact: The proposed method shows the ability to identify the fluid compartments on CEST images,which can help mitigate fluid artifacts in quantitative analysis and improve image reading.