Document Detail


White-marker imaging--separating magnetic susceptibility effects from partial volume effects.
MedLine Citation:
PMID:  17628486     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
By applying dephasing gradients, local magnetic field inhomogeneitiescan selectively visualized with positive contrast, such as those created by magnetically labeled cells. This is known as "white-marker imaging." In white-marker imaging, subvoxel signal variations are also visualized as a result of partial volume (PV) effects and may compromise the identification of magnetic structures (e.g., magnetically-labeled cells). This study presents the theory and proof-of-principle experiments of a strategy to eliminate PV effects during white-marker imaging. The strategy employs the asymmetry of the signal response curves for non-PV effects as a function of externally applied gradients. In the case of PV effects, subtraction of the symmetrical signal responses eliminates their contribution. In vitro experimental images were made using a spherical phantom with cylindrical elements. In vivo images of the brain were obtained at a location that included air cavities (susceptibility effects) and the circle of Willis (PV effect). The results show that PV effects were eliminated in the in vitro experiments and were virtually absent under in vivo conditions.
Authors:
Jan-Henry Seppenwoolde; Koen L Vincken; Chris J G Bakker
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine     Volume:  58     ISSN:  0740-3194     ISO Abbreviation:  Magn Reson Med     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-05     Completed Date:  2007-12-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  605-9     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2007 Wiley-Liss, Inc.
Affiliation:
Image Sciences Institute, University Medical Center Utrecht, Department of Radiology, The Netherlands. janhenry@isi.uu.nl
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MeSH Terms
Descriptor/Qualifier:
Air
Algorithms
Artifacts
Brain / anatomy & histology
Circle of Willis / anatomy & histology
Contrast Media
Echo-Planar Imaging / methods
Humans
Image Enhancement / methods*
Image Processing, Computer-Assisted / methods
Imaging, Three-Dimensional / methods
Magnetic Resonance Imaging / methods*
Phantoms, Imaging
Subtraction Technique
Chemical
Reg. No./Substance:
0/Contrast Media

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


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