title: Transverse relaxation of selectively excited metabolites in stroke at 21.1 T.
abstract: This study seeks to evaluate in vivo T2relaxation times of selectively excited stroke-relevant metabolites via1H relaxation-enhanced magnetic resonance spectroscopy (RE-MRS) at 21.1 T (900 MHz).
  
  
  
  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 T2measurements. 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.
  
  
  
  The RE-MRS approach produced high-quality spectra of the selectively excited metabolites in the stroked and contralateral regions. T2measurements reveal differential results between these regions, with significance achieved for lactic acid.
  
  
  
  Using the RE-MRS technique at ultra-high magnetic field and an optimized quadrature surface coil design, full metabolic T2quantifications 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.
authors.affiliation: The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.
authors.forename: Jens T
authors.initials: JT
authors.lastname: Rosenberg
authors.affiliation: Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.
authors.forename: Noam
authors.initials: N
authors.lastname: Shemesh
authors.affiliation: The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.|Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Muniz
authors.affiliation: French National Centre for Scientific Research, Institute de Chime des Substances Naturelles, Gif-sur-Yvette, France.
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Dumez
authors.affiliation: The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.|Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Lucio
authors.initials: L
authors.lastname: Frydman
authors.affiliation: The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.|Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA.
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Grant
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D066244:Proton Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D020521:Stroke / Q000378:metabolism*; D014159:Transducers / Q000662:veterinary*
chemical_list: D019344:Lactic Acid
keywords: 21.1 T MRS; T2; metabolites; relaxation; stroke; ultrahigh field MRI