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Improving B 0 Correction for pH-Weighted Amine Proton Chemical Exchange Saturation Transfer (CEST) Imaging by Use of k-Means Clustering and Lorentzian Estimation.

Authors :
Yao J
Ruan D
Raymond C
Liau LM
Salamon N
Pope WB
Nghiemphu PL
Lai A
Cloughesy TF
Ellingson BM
Source :
Tomography (Ann Arbor, Mich.) [Tomography] 2018 Sep; Vol. 4 (3), pp. 123-137.
Publication Year :
2018

Abstract

Amine chemical exchange saturation transfer (CEST) echoplanar imaging (EPI) provides unique pH and amino acid MRI contrast, enabling sensitive detection of altered microenvironment properties in various diseases. However, CEST contrast is sensitive to static magnetic field (B <subscript>0</subscript> ) inhomogeneities. Here we propose 2 new B <subscript>0</subscript> correction algorithms for use in correcting pH-weighted amine CEST EPI based on k-means clustering and Lorentzian fitting of CEST data: the iterative downsampling estimation using Lorentzian fitting and the 2-stage Lorentzian estimation with 4D polynomial fitting. Higher quality images of asymmetric magnetization transfer ratio (MTR <subscript>asym</subscript> ) at 3.0 ppm could be obtained with the proposed algorithms than with the existing B <subscript>0</subscript> correction methods. In particular, the proposed methods are shown to improve the intertissue consistency, interpatient consistency, and tumor region signal-to-noise ratio of MTR <subscript>asym</subscript> at 3.0 ppm images, with nonexcessive computation time.<br />Competing Interests: Conflict of Interest: The authors have no conflict of interest to declare.

Details

Language :
English
ISSN :
2379-139X
Volume :
4
Issue :
3
Database :
MEDLINE
Journal :
Tomography (Ann Arbor, Mich.)
Publication Type :
Academic Journal
Accession number :
30320212
Full Text :
https://doi.org/10.18383/j.tom.2018.00017