Sofie Tapper1,2, Steve C N Hui1,2, Muhammad G Saleh3, Helge J Zöllner1,2, Georg Oeltzschner1,2, Jamie Near4,5, Brian J Soher6, Richard A E Edden1,2. 1. Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. 2. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA. 3. Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA. 4. Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada. 5. Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada. 6. Center for Advanced MR Development, Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA.
Abstract
PURPOSE: To investigate the editing-pulse flip angle (FA) dependence of editing efficiency and ultimately to maximize the edited signal of commonly edited MR spectroscopy (MRS) signals, such as gamma-aminobutyric acid (GABA) and lactate. METHODS: Density-matrix simulations were performed for a range of spin systems to find the editing-pulse FA for maximal editing efficiency. Simulations were confirmed by phantom experiments and in vivo measurements in 10 healthy participants using a 3T Philips scanner. Four MEGA-PRESS in vivo measurements targeting GABA+ and lactate were performed, comparing the conventional editing-pulse FA (FA = 180°) to the optimal one suggested by simulations (FA = 210°). RESULTS: Simulations and phantom experiments show that edited GABA and lactate signals are maximal at FA = 210°. Compared to conventional editing (FA = 180°), in vivo signals from GABA+ and lactate signals increase on average by 8.5% and 9.3%, respectively. CONCLUSION: Increasing the FA of editing-pulses in the MEGA-PRESS experiment from 180° to 210° increases the edited signals from GABA+ and lactate by about 9% in vivo.
PURPOSE: To investigate the editing-pulse flip angle (FA) dependence of editing efficiency and ultimately to maximize the edited signal of commonly edited MR spectroscopy (MRS) signals, such as gamma-aminobutyric acid (GABA) and lactate. METHODS: Density-matrix simulations were performed for a range of spin systems to find the editing-pulse FA for maximal editing efficiency. Simulations were confirmed by phantom experiments and in vivo measurements in 10 healthy participants using a 3T Philips scanner. Four MEGA-PRESS in vivo measurements targeting GABA+ and lactate were performed, comparing the conventional editing-pulse FA (FA = 180°) to the optimal one suggested by simulations (FA = 210°). RESULTS: Simulations and phantom experiments show that edited GABA and lactate signals are maximal at FA = 210°. Compared to conventional editing (FA = 180°), in vivo signals from GABA+ and lactate signals increase on average by 8.5% and 9.3%, respectively. CONCLUSION: Increasing the FA of editing-pulses in the MEGA-PRESS experiment from 180° to 210° increases the edited signals from GABA+ and lactate by about 9% in vivo.
Authors: Mark Mikkelsen; Peter B Barker; Pallab K Bhattacharyya; Maiken K Brix; Pieter F Buur; Kim M Cecil; Kimberly L Chan; David Y-T Chen; Alexander R Craven; Koen Cuypers; Michael Dacko; Niall W Duncan; Ulrike Dydak; David A Edmondson; Gabriele Ende; Lars Ersland; Fei Gao; Ian Greenhouse; Ashley D Harris; Naying He; Stefanie Heba; Nigel Hoggard; Tun-Wei Hsu; Jacobus F A Jansen; Alayar Kangarlu; Thomas Lange; R Marc Lebel; Yan Li; Chien-Yuan E Lin; Jy-Kang Liou; Jiing-Feng Lirng; Feng Liu; Ruoyun Ma; Celine Maes; Marta Moreno-Ortega; Scott O Murray; Sean Noah; Ralph Noeske; Michael D Noseworthy; Georg Oeltzschner; James J Prisciandaro; Nicolaas A J Puts; Timothy P L Roberts; Markus Sack; Napapon Sailasuta; Muhammad G Saleh; Michael-Paul Schallmo; Nicholas Simard; Stephan P Swinnen; Martin Tegenthoff; Peter Truong; Guangbin Wang; Iain D Wilkinson; Hans-Jörg Wittsack; Hongmin Xu; Fuhua Yan; Chencheng Zhang; Vadim Zipunnikov; Helge J Zöllner; Richard A E Edden Journal: Neuroimage Date: 2017-07-14 Impact factor: 6.556
Authors: Kimberly L Chan; Nicolaas A J Puts; Karim Snoussi; Ashley D Harris; Peter B Barker; Richard A E Edden Journal: Magn Reson Med Date: 2016-02-25 Impact factor: 4.668
Authors: Richard A E Edden; Nicolaas A J Puts; Ashley D Harris; Peter B Barker; C John Evans Journal: J Magn Reson Imaging Date: 2013-11-13 Impact factor: 4.813
Authors: Muhammad G Saleh; Daniel Rimbault; Mark Mikkelsen; Georg Oeltzschner; Anna M Wang; Dengrong Jiang; Ali Alhamud; Jamie Near; Michael Schär; Ralph Noeske; James B Murdoch; Lars Ersland; Alexander R Craven; Gerard Eric Dwyer; Eli Renate Grüner; Li Pan; Sinyeob Ahn; Richard A E Edden Journal: Neuroimage Date: 2019-01-22 Impact factor: 6.556