Document Detail


Correction of physiologically induced global off-resonance effects in dynamic echo-planar and spiral functional imaging.
MedLine Citation:
PMID:  11810679     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In functional magnetic resonance imaging, a rapid method such as echo-planar (EPI) or spiral is used to collect a dynamic series of images. These techniques are sensitive to changes in resonance frequency which can arise from respiration and are more significant at high magnetic fields. To decrease the noise from respiration-induced phase and frequency fluctuations, a simple correction of the "dynamic off-resonance in k-space" (DORK) was developed. The correction uses phase information from the center of k-space and a navigator echo and is illustrated with dynamic scans of single-shot and segmented EPI and, for the first time, spiral imaging of the human brain at 7 T. Image noise in the respiratory spectrum was measured with an edge operator. The DORK correction significantly reduced respiration-induced noise (image shift for EPI, blurring for spiral, ghosting for segmented acquisition). While spiral imaging was found to exhibit less noise than EPI before correction, the residual noise after the DORK correction was comparable. The correction is simple to apply and can correct for other sources of frequency drift and fluctuations in dynamic imaging.
Authors:
Josef Pfeuffer; Pierre-Francois Van de Moortele; Kamil Ugurbil; Xiaoping Hu; Gary H Glover
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine     Volume:  47     ISSN:  0740-3194     ISO Abbreviation:  Magn Reson Med     Publication Date:  2002 Feb 
Date Detail:
Created Date:  2002-01-25     Completed Date:  2002-04-15     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  344-53     Citation Subset:  IM    
Copyright Information:
Copyright 2002 Wiley-Liss, Inc.
Affiliation:
Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA. josef.pfeuffer@tuebingen.mpg.de
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MeSH Terms
Descriptor/Qualifier:
Adult
Artifacts
Brain Mapping
Echo-Planar Imaging / methods*
Female
Humans
Image Enhancement / methods*
Image Processing, Computer-Assisted / methods*
Magnetic Resonance Imaging / methods*
Male
Photic Stimulation
Reference Values
Visual Cortex / physiology*
Grant Support
ID/Acronym/Agency:
R01MH55346/MH/NIMH NIH HHS; RR08079/RR/NCRR NIH HHS; RR09784/RR/NCRR NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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