Document Detail

Minimising the effects of bolus dispersion in bolus-tracking MRI.
MedLine Citation:
PMID:  18727165     Owner:  NLM     Status:  MEDLINE    
Bolus-tracking perfusion measurements in patients with vascular abnormalities are often unreliable, because delay and/or dispersion of the bolus within the vessels distorts the measured arterial input function (AIF). Erroneous measurements of perfusion can be identified by examining the measured response function, the shape of which is determined by both the tissue and arterial retention. In this work, an accurate response function is extracted by combining maximum-likelihood expectation-maximisation deconvolution, regularised using an oscillation index, with subsequent wavelet thresholding. Simulations show that this method recovers both the smooth-dispersed and the sharp-delayed response functions. This enables regions where the bolus is delayed and/or dispersed to be identified when the methodology is applied to data from patients with vascular abnormalities. Simulations also demonstrate robust and accurate perfusion estimates when there is no bolus delay and/or dispersion. The presence of delay and/or dispersion in the response function suggests that the perfusion measurements are erroneous, and that the global AIF is an inaccurate approximation to the true AIF in these regions. Perfusion measurements are corrected within the affected regions by defining a regional AIF from the independent component analysis of the dynamic susceptibility contrast MRI data. The regional AIF is shown to remove the delay and dispersion, improving the accuracy of the perfusion maps.
L Willats; A Connelly; F Calamante
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  NMR in biomedicine     Volume:  21     ISSN:  0952-3480     ISO Abbreviation:  NMR Biomed     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2008-12-01     Completed Date:  2009-02-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8915233     Medline TA:  NMR Biomed     Country:  England    
Other Details:
Languages:  eng     Pagination:  1126-37     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2008 John Wiley & Sons, Ltd.
Radiology and Physics Unit, UCL Institute of Child Health, London, UK.
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MeSH Terms
Brain / blood supply,  physiology*
Cerebrovascular Circulation / physiology*
Computer Simulation
Contrast Media / administration & dosage,  pharmacokinetics*
Image Enhancement / methods*
Image Interpretation, Computer-Assisted / methods
Magnetic Resonance Imaging / methods*
Models, Biological*
Reg. No./Substance:
0/Contrast Media

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

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