Yi Zhang1,2, Jinyuan Zhou1,3, Paul A Bottomley1,2. 1. Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA. 2. Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA. 3. F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA.
Abstract
PURPOSE: Low spatial resolution in conventional 1H brain chemical shifting imaging (CSI) studies causes partial volume error (PVE) or signal "bleed" that is especially deleterious to voxels near the scalp. The standard spatial apodization approach adversely affects spatial resolution. Here, a novel automated post-processing strategy of partial volume correction employing grid shifting ("PANGS") is presented, which minimizes residual PVE without compromising spatial resolution. METHODS: PANGS shifts the locations of the reconstruction coordinates in a designated region of image space-the scalp, to match the tissue "centers-of-mass" instead of the geometric centers of each voxel, by iteratively minimizing the PVE from the scalp into outside voxels. PANGS' performance was evaluated by numerical simulation, and in 3 Tesla 1H CSI human studies employing outer volume suppression and long echo times. RESULTS: PANGS reduced lipid contamination of cortical spectra by up to 86% (54% on average). Metabolite maps exhibited significantly less lipid artifact than conventional and spatially-filtered CSI. All methods generated quantitatively identical spectral peak areas from central brain locations, but spatial filtering increased spectral linewidths and reduced spatial resolution. CONCLUSION: PANGS significantly reduces lipid artifacts in 1H brain CSI spectra and metabolite maps, and improves metabolite detection in cortical regions without compromising resolution.
PURPOSE: Low spatial resolution in conventional 1H brain chemical shifting imaging (CSI) studies causes partial volume error (PVE) or signal "bleed" that is especially deleterious to voxels near the scalp. The standard spatial apodization approach adversely affects spatial resolution. Here, a novel automated post-processing strategy of partial volume correction employing grid shifting ("PANGS") is presented, which minimizes residual PVE without compromising spatial resolution. METHODS: PANGS shifts the locations of the reconstruction coordinates in a designated region of image space-the scalp, to match the tissue "centers-of-mass" instead of the geometric centers of each voxel, by iteratively minimizing the PVE from the scalp into outside voxels. PANGS' performance was evaluated by numerical simulation, and in 3 Tesla 1H CSI human studies employing outer volume suppression and long echo times. RESULTS: PANGS reduced lipid contamination of cortical spectra by up to 86% (54% on average). Metabolite maps exhibited significantly less lipid artifact than conventional and spatially-filtered CSI. All methods generated quantitatively identical spectral peak areas from central brain locations, but spatial filtering increased spectral linewidths and reduced spatial resolution. CONCLUSION: PANGS significantly reduces lipid artifacts in 1H brain CSI spectra and metabolite maps, and improves metabolite detection in cortical regions without compromising resolution.
Authors: T K Tran; D B Vigneron; N Sailasuta; J Tropp; P Le Roux; J Kurhanewicz; S Nelson; R Hurd Journal: Magn Reson Med Date: 2000-01 Impact factor: 4.668
Authors: J V Hajnal; D J Bryant; L Kasuboski; P M Pattany; B De Coene; P D Lewis; J M Pennock; A Oatridge; I R Young; G M Bydder Journal: J Comput Assist Tomogr Date: 1992 Nov-Dec Impact factor: 1.826
Authors: J V Hajnal; B De Coene; P D Lewis; C J Baudouin; F M Cowan; J M Pennock; I R Young; G M Bydder Journal: J Comput Assist Tomogr Date: 1992 Jul-Aug Impact factor: 1.826
Authors: Martin Wilson; Ovidiu Andronesi; Peter B Barker; Robert Bartha; Alberto Bizzi; Patrick J Bolan; Kevin M Brindle; In-Young Choi; Cristina Cudalbu; Ulrike Dydak; Uzay E Emir; Ramon G Gonzalez; Stephan Gruber; Rolf Gruetter; Rakesh K Gupta; Arend Heerschap; Anke Henning; Hoby P Hetherington; Petra S Huppi; Ralph E Hurd; Kejal Kantarci; Risto A Kauppinen; Dennis W J Klomp; Roland Kreis; Marijn J Kruiskamp; Martin O Leach; Alexander P Lin; Peter R Luijten; Małgorzata Marjańska; Andrew A Maudsley; Dieter J Meyerhoff; Carolyn E Mountford; Paul G Mullins; James B Murdoch; Sarah J Nelson; Ralph Noeske; Gülin Öz; Julie W Pan; Andrew C Peet; Harish Poptani; Stefan Posse; Eva-Maria Ratai; Nouha Salibi; Tom W J Scheenen; Ian C P Smith; Brian J Soher; Ivan Tkáč; Daniel B Vigneron; Franklyn A Howe Journal: Magn Reson Med Date: 2019-03-28 Impact factor: 4.668