Document Detail

Experimental hypoxemic hypoxia: changes in R2* of brain parenchyma accurately reflect the combined effects of changes in arterial and cerebral venous oxygen saturation.
MedLine Citation:
PMID:  9498604     Owner:  NLM     Status:  MEDLINE    
A two-dimensional T2*-weighted gradient-echo sequence was used to image the rat brain before and during graded hypoxemia. Changes in R2* (deltaR2*) with respect to the control state were calculated for brain parenchyma and were compared with changes in hemoglobin saturation measured from both arterial and jugular venous blood samples. DeltaR2* was first correlated with the changes in arterial (deltaYa) and venous (deltaYv) hemoglobin saturations individually. Although a general trend toward a linear relationship with deltaR2* was observed for both deltaYa and deltaYv, neither alone was strong (correlation coefficients r=0.71 and 0.75 for deltaYa and deltaYv, respectively, and standard errors of the regression (SER)=0.52 and 0.48 for deltaYa and deltaYv, respectively). However, when an "effective" cerebral blood hemoglobin saturation change (deltaYb) was constructed that takes into account the approximate weighting of the contributions from the arterial and venous phases of the circulation (deltaYb = 0.75 x deltaYv + 0.25 x deltaYa), a stronger correlation with deltaR2* was obtained and there was less variance (r=0.87 and SER=0.35). It is concluded that an appropriate weighting of the contributions of arterial and venous phases of the circulation must be taken into account in modeling the volume susceptibility effects of deoxyhemoglobin on R2* of brain parenchyma. In this way, a more accurate relationship between deltaR2* and deltaYb can be obtained.
W Lin; R P Paczynski; A Celik; K Kuppusamy; C Y Hsu; W J Powers
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Publication Detail:
Type:  Comparative Study; 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:  39     ISSN:  0740-3194     ISO Abbreviation:  Magn Reson Med     Publication Date:  1998 Mar 
Date Detail:
Created Date:  1998-04-30     Completed Date:  1998-04-30     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8505245     Medline TA:  Magn Reson Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  474-81     Citation Subset:  IM    
Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110, USA.
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MeSH Terms
Analysis of Variance
Anoxia / blood*,  metabolism
Aorta, Thoracic
Blood Volume
Brain / metabolism*
Carbon Dioxide / blood
Cerebral Veins
Cerebrovascular Circulation
Cranial Sinuses
Hemoglobins / metabolism
Image Processing, Computer-Assisted
Jugular Veins
Magnetic Resonance Imaging*
Oxygen / blood*
Oxyhemoglobins / metabolism
Regression Analysis
Subtraction Technique
Grant Support
Reg. No./Substance:
0/Hemoglobins; 0/Oxyhemoglobins; 124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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

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