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Transverse relaxation of selectively excited metabolites in stroke at 21.1 T
Author(s) -
Rosenberg Jens T.,
Shemesh Noam,
Muniz Jose A.,
Dumez JeanNicolas,
Frydman Lucio,
Grant Samuel C.
Publication year - 2017
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.26132
Subject(s) - excited state , nuclear magnetic resonance , stroke (engine) , relaxation (psychology) , chemistry , physics , neuroscience , atomic physics , psychology , thermodynamics
Purpose This study seeks to evaluate in vivo T 2 relaxation times of selectively excited stroke‐relevant metabolites via 1 H relaxation‐enhanced magnetic resonance spectroscopy (RE‐MRS) at 21.1 T (900 MHz). Methods A quadrature surface coil was designed and optimized for investigations of rodents at 21.1 T. With voxel localization, a RE‐MRS pulse sequence incorporating the excitation of selected metabolites was modified to include a variable echo delay for T 2 measurements. A middle cerebral artery occlusion (MCAO) animal model for stroke was examined with spectra taken 24 h post occlusion. Fourteen echo times were acquired, with each measurement completed in less than 2 min. Results The RE‐MRS approach produced high‐quality spectra of the selectively excited metabolites in the stroked and contralateral regions. T 2 measurements reveal differential results between these regions, with significance achieved for lactic acid. Conclusion Using the RE‐MRS technique at ultra‐high magnetic field and an optimized quadrature surface coil design, full metabolic T 2 quantifications in a localized voxel is now possible in less than 27 min. Magn Reson Med 77:520–528, 2017. © 2016 International Society for Magnetic Resonance in Medicine