PURPOSE: To investigate the effect of Carr-Purcell (CP) pulse trains on transverse relaxation times, T2, of tissue water and metabolites (both noncoupled and J-coupled spins) in the rat brain at 9.4 Tesla (T) using LASER, CP-LASER, and T2ρ-LASER sequences. METHODS: Proton NMR spectra were measured in rat brain in vivo at 9.4T. Spectra were acquired at multiple echo times ranging from 18 to 402 ms. All spectra were analyzed using LCModel with simulated basis sets. Signals of metabolites as a function of echo time were fitted using a mono-exponential function to determine their T2 relaxation times. RESULTS: Measured T2 s for tissue water and all metabolites were significantly longer with CP-LASER and T2ρ-LASER compared with LASER. The T2 increased by a factor of ∼ 1.3 for noncoupled and weakly coupled spins (e.g., N-acetylaspartate and total creatine) and by a factor of ∼ 2 (e.g., glutamine and taurine) to ∼ 4 (e.g., glutamate and myo-inositol) for strongly coupled spins. CONCLUSION: Application of a CP pulse train results in a larger increase in T2 relaxation times for strongly coupled spins than for noncoupled (singlet) and weakly coupled spins. This needs to be taken into account when correcting for T2 relaxation in CP-like sequences such as LASER.
PURPOSE: To investigate the effect of Carr-Purcell (CP) pulse trains on transverse relaxation times, T2, of tissue water and metabolites (both noncoupled and J-coupled spins) in the rat brain at 9.4 Tesla (T) using LASER, CP-LASER, and T2ρ-LASER sequences. METHODS: Proton NMR spectra were measured in rat brain in vivo at 9.4T. Spectra were acquired at multiple echo times ranging from 18 to 402 ms. All spectra were analyzed using LCModel with simulated basis sets. Signals of metabolites as a function of echo time were fitted using a mono-exponential function to determine their T2 relaxation times. RESULTS: Measured T2 s for tissue water and all metabolites were significantly longer with CP-LASER and T2ρ-LASER compared with LASER. The T2 increased by a factor of ∼ 1.3 for noncoupled and weakly coupled spins (e.g., N-acetylaspartate and total creatine) and by a factor of ∼ 2 (e.g., glutamine and taurine) to ∼ 4 (e.g., glutamate and myo-inositol) for strongly coupled spins. CONCLUSION: Application of a CP pulse train results in a larger increase in T2 relaxation times for strongly coupled spins than for noncoupled (singlet) and weakly coupled spins. This needs to be taken into account when correcting for T2 relaxation in CP-like sequences such as LASER.
Authors: Gülin Öz; Dinesh K Deelchand; Jannie P Wijnen; Vladimír Mlynárik; Lijing Xin; Ralf Mekle; Ralph Noeske; Tom W J Scheenen; Ivan Tkáč Journal: NMR Biomed Date: 2020-01-10 Impact factor: 4.044
Authors: Dinesh K Deelchand; Adam Berrington; Ralph Noeske; James M Joers; Arvin Arani; Joseph Gillen; Michael Schär; Jon-Fredrik Nielsen; Scott Peltier; Navid Seraji-Bozorgzad; Karl Landheer; Christoph Juchem; Brian J Soher; Douglas C Noll; Kejal Kantarci; Eva M Ratai; Thomas H Mareci; Peter B Barker; Gülin Öz Journal: NMR Biomed Date: 2019-12-18 Impact factor: 4.044
Authors: Wolfgang Bogner; Borjan Gagoski; Aaron T Hess; Himanshu Bhat; M Dylan Tisdall; Andre J W van der Kouwe; Bernhard Strasser; Małgorzata Marjańska; Siegfried Trattnig; Ellen Grant; Bruce Rosen; Ovidiu C Andronesi Journal: Neuroimage Date: 2014-09-26 Impact factor: 6.556
Authors: Adam Berrington; Natalie L Voets; Puneet Plaha; Sarah J Larkin; James Mccullagh; Richard Stacey; Muhammed Yildirim; Christopher J Schofield; Peter Jezzard; Tom Cadoux-Hudson; Olaf Ansorge; Uzay E Emir Journal: Tomography Date: 2016-06