Development of intravoxel inhomogeneity correction for chemical exchange saturation transfer spectral imaging: a high-resolution field map-based deconvolution algorithm for magnetic field inhomogeneity correction

• Type of Material: Article
• Authors: Phillip Zhe Sun, Emory University
• Language: English
• Date: 2020-04-01
• Publisher: WILEY
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2019 International Society for Magnetic Resonance in Medicine
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1002/mrm.28015
• Title of Journal or Parent Work: MAGNETIC RESONANCE IN MEDICINE
• Volume: 83
• Issue: 4
• Start Page: 1348
• End Page: 1355
• Grant/Funding Information: This study was supported in part by grants from NIH/NINDS R01NS083654 (to Sun), NIH/NIAMS R21AR071529 (to Sun) and P51OD011132–58 (to Yerkes National Primate Research Center).
• Keywords: IN-VIVO; WATER; CONTRAST AGENTS; PH; QUANTITATIVE DESCRIPTION; TRANSFER CEST MRI; ACIDOSIS; Science & Technology; REPORTER GENE; PROTEINS; Life Sciences & Biomedicine; Radiology, Nuclear Medicine & Medical Imaging; RELAXATION

Abstract

Purpose: CEST MRI is sensitive to dilute proteins/peptides and microenvironmental properties yet susceptible to magnetic field inhomogeneity. We aimed to develop a high-resolution field map-based CEST intravoxel inhomogeneity correction (CIVIC) algorithm for CEST Z-spectral imaging. Methods: The proposed CIVIC approach treats the intravoxel inhomogeneity as a point spread function and applies the deconvolution algorithm to reconstruct the original Z-spectrum. We simulated the effect of B0 field inhomogeneity on CEST measurement and tested the efficacy of the proposed CIVIC algorithm. We also performed CEST MRI on a dual-pH Creatine-gel phantom under varied field homogeneity conditions and compared the CEST MRI contrast-to-noise ratio from the raw Z-spectrum, water saturation shift referencing, and the proposed CIVIC methods. Results: The numerical simulation showed that the CIVIC algorithm remains effective even in the case of symmetric field dispersion with a 0 mean shift. The experimental results confirmed that the proposed CIVIC method substantially improves the CEST MRI contrast-to-noise ratio under different field homogeneity conditions. Conclusion: Our study established a new intravoxel B0 inhomogeneity correction algorithm, promising to facilitate CEST spectral imaging in challenging experimental conditions.