Document Detail

Improved accuracy of human cerebral blood perfusion measurements using arterial spin labeling: accounting for capillary water permeability.
MedLine Citation:
PMID:  12111929     Owner:  NLM     Status:  MEDLINE    
A two-compartment exchange model for perfusion quantification using arterial spin labeling (ASL) is presented, which corrects for the assumption that the capillary wall has infinite permeability to water. The model incorporates an extravascular and a blood compartment with the permeability surface area product (PS) of the capillary wall characterizing the passage of water between the compartments. The new model predicts that labeled spins spend longer in the blood compartment before exchange. This makes an accurate blood T(1) measurement crucial for perfusion quantification; conversely, the tissue T(1) measurement is less important and may be unnecessary for pulsed ASL experiments. The model gives up to 62% reduction in perfusion estimate for human imaging at 1.5T compared to the single compartment model. For typical human perfusion rates at 1.5T it can be assumed that the venous outflow signal is negligible. This simplifies the solution, introducing only one more parameter than the single compartment model, PS/v(bw), where v(bw) is the fractional blood water volume per unit volume of tissue. The simplified model produces an improved fit to continuous ASL data collected at varying delay time. The fitting yields reasonable values for perfusion and PS/v(bw).
Laura M Parkes; Paul S Tofts
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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:  48     ISSN:  0740-3194     ISO Abbreviation:  Magn Reson Med     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-11     Completed Date:  2002-09-17     Revised Date:  2011-11-03    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  27-41     Citation Subset:  IM    
Copyright Information:
Copyright 2002 Wiley-Liss, Inc.
NMR Research Unit, Institute of Neurology, University College London, Queen Square, London, UK.
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MeSH Terms
Capillary Permeability / physiology*
Cerebrovascular Circulation / physiology*
Electron Spin Resonance Spectroscopy*
Models, Cardiovascular
Grant Support
491//Multiple Sclerosis Society

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

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