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NOrmalized MAgnetization Ratio (NOMAR) filtering for creation of tissue selective contrast maps
Author(s) -
Liu Guanshu,
Chan Kannie W. Y.,
Song Xiaolei,
Zhang Jiangyang,
Gilad Assaf A.,
Bulte Jeff W. M.,
van Zijl Peter C. M.,
McMahon Michael T.
Publication year - 2013
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24271
Subject(s) - magnetization transfer , voxel , nuclear magnetic resonance , contrast (vision) , saturation (graph theory) , diamagnetism , imaging phantom , histogram , segmentation , chemistry , materials science , biomedical engineering , biological system , computer science , magnetic resonance imaging , nuclear medicine , artificial intelligence , physics , mathematics , radiology , medicine , biology , magnetic field , combinatorics , quantum mechanics , image (mathematics)
Abstract An MRI segmentation technique based on collecting two additional saturation transfer images is proposed as an aid for improved detection of chemical exchange saturation transfer agents. In this approach, the additional images are acquired at saturation frequencies of −12.5 and −50 ppm. Use of the ratio of these images allows differentiation of voxels with low magnetization transfer contrast (such as fat, cerebrospinal fluid, edema, or blood) from target tissue voxels using a global threshold determined by histogram analysis. We demonstrate that this technique can reduce artifacts, in vitro, in a phantom containing tubes with chemical exchange saturation transfer contrast agent embedded in either crosslinked bovine serum albumin or buffer, and in vivo for detecting diamagnetic CEST (DIACEST) liposomes injected into mice. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.