Premium
UCEPR: Ultrafast localized CEST‐spectroscopy with PRESS in phantoms and in vivo
Author(s) -
Liu Zheng,
Dimitrov Ivan E.,
Lenkinski Robert E.,
Hajibeigi Asghar,
Vinogradov Elena
Publication year - 2016
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.25780
Subject(s) - ultrashort pulse , nuclear magnetic resonance , spectroscopy , chemistry , saturation (graph theory) , resolution (logic) , nuclear magnetic resonance spectroscopy , in vivo magnetic resonance spectroscopy , voxel , analytical chemistry (journal) , optics , physics , magnetic resonance imaging , laser , quantum mechanics , medicine , mathematics , combinatorics , artificial intelligence , chromatography , computer science , radiology
Purpose Chemical exchange saturation transfer (CEST) is a contrast mechanism enhancing low‐concentration molecules through saturation transfer from their exchangeable protons to bulk water. Often many scans are acquired to form a Z‐ spectrum, making the CEST method time‐consuming. Here, an ultrafast localized CEST‐spectroscopy with PRESS (UCEPR) is proposed to obtain the entire Z‐ spectrum of a voxel using only two scans, significantly accelerating CEST. Theory and Methods The approach combines ultrafast nonlocalized CEST spectroscopy with localization using PRESS. A field gradient is applied concurrently with the saturation pulse producing simultaneous saturation of all Z‐ spectrum frequencies that are also spatially encoded. A readout gradient during data acquisition resolves the spatial dependence of the CEST responses into frequency. UCEPR was tested on a 3T scanner both in phantoms and in vivo. Results In phantoms, a fast Z‐ spectroscopy acquisition of multiple pH‐variant iopamidol samples was achieved with four‐ to seven‐fold acceleration as compared to the conventional CEST methods. In vivo, amide proton transfer (APT) in white matter of healthy human brain was measured rapidly in 48 s and with high frequency resolution (≤ 0.2 ppm). Conclusion Compared with conventional CEST methods, UCEPR has the advantage of rapidly acquiring high‐resolution Z‐ spectra. Potential in vivo applications include ultrafast localized Z‐spectroscopy, quantitative, or dynamic CEST studies. Magn Reson Med 75:1875–1885, 2016. © 2015 Wiley Periodicals, Inc.