Document Detail


Experimental estimates of the constants relating signal change to contrast concentration for cerebral blood volume by T2* MRI.
MedLine Citation:
PMID:  16319833     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Estimates of cerebral blood volume (CBV) obtained from dynamic contrast T2(*)-weighted magnetic resonance imaging (MRI) tend to be significantly higher than values obtained by other methods. This may relate to the common assumption that the proportionality constants relating signal change to contrast concentration are equal in tissue and artery. To test this hypothesis and provide estimates for the ratio of those proportionality constants, the authors compared measurements of CBV by both MRI and computed tomography (CT) scans in nine healthy volunteers obtained using identical kinetic paradigms for the two imaging modalities. Both boluses and infusions of contrast were studied. Measurements were made in nine anatomic regions of interest of the cerebral hemispheres bilaterally. Cerebral blood volume values obtained by CT were generally lower than those obtained by MRI, especially in the cerebral cortex. As a result, the calculated values of the ratios of proportionality constants relating signal change to concentration in tissue and artery after bolus injections were significantly less than 1 in cortex (0.69) and white matter (0.76), although not in deep gray matter structures (0.87). Values of the ratios based on infusion measurements were closer to 1. In addition, CBV measurement errors with bolus MRI were significantly larger than those observed with infusion MRI or by CT. The reasons that the constants differ from 1 and for the larger variance of bolus MRI are discussed in terms of the T2* signal mechanisms. These studies help define the magnitude by which CBV is overestimated with typical T2*-weighted perfusion imaging. Infusion measurements of CBV can reduce the variance intrinsic to T2* MRI and lessen the likelihood of type II error.
Authors:
George C Newman; Frank E Hospod; Clifford S Patlak; Sean E Fain; Kari A Pulfer; Thomas D Cook; Finbarr O'Sullivan
Related Documents :
7904843 - Early and late ct manifestations in the persistent vegetative state due to cerebral ano...
8585503 - Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopa...
1728773 - Pharmacologic perfusion imaging. who needs it and why?
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism     Volume:  26     ISSN:  0271-678X     ISO Abbreviation:  J. Cereb. Blood Flow Metab.     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-23     Completed Date:  2006-07-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8112566     Medline TA:  J Cereb Blood Flow Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  760-70     Citation Subset:  IM    
Affiliation:
Department of Neurology, University of Wisconsin School of Medicine, Madison, Wisconsin, USA. NewmanG@einstein.edu
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adult
Area Under Curve
Blood Flow Velocity / physiology
Blood Volume / physiology
Blood Volume Determination / methods
Brain / physiology*
Cerebrovascular Circulation / physiology*
Contrast Media / administration & dosage*
Female
Gadolinium DTPA / administration & dosage*,  diagnostic use
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging*
Male
Middle Aged
Tomography, X-Ray Computed
Chemical
Reg. No./Substance:
0/Contrast Media; 80529-93-7/Gadolinium DTPA

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


Previous Document:  The vertical profile of winds on Titan.
Next Document:  Relationship of total body fatness and five anthropometric indices in Chinese aged 20-40 years: diff...