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Quantitative tracking of edema, hemorrhage, and microvascular obstruction in subacute myocardial infarction in a porcine model by MRI
Author(s) -
Ghugre Nilesh R.,
Ramanan Venkat,
Pop Mihaela,
Yang Yuesong,
Barry Jennifer,
Qiang Beiping,
Connelly Kim A.,
Dick Alexander J.,
Wright Graham A.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22855
Subject(s) - medicine , edema , infarction , myocardial infarction , magnetic resonance imaging , in vivo , cardiology , grading (engineering) , inflammation , microcirculation , pathology , radiology , engineering , civil engineering , microbiology and biotechnology , biology
Pathophysiological responses after acute myocardial infarction include edema, hemorrhage, and microvascular obstruction along with cellular damage. The in vivo evolution of these processes simultaneously throughout infarct healing has not been well characterized. The purpose of our study was to quantitatively monitor the time course of these mechanisms by MRI in a porcine model of myocardial infarction. Ten pigs underwent MRI before coronary occlusion with subgroups studied at day 2 and weeks 1, 2, 4, and 6 post‐infarction. Tissue characterization was performed using quantitative T2 and T2* maps to identify edema and hemorrhage, respectively. Contrast‐enhanced MRI was used for infarct/ microvascular obstruction delineation. Inflammation was reflected by T2 fluctuations, however at day 2, edema and hemorrhage had counter‐acting effects on T2. Hemorrhage (all forms) and mineralization (calcium) could be identified by T2* in the presence of edema. Simultaneous resolution of microvascular obstruction and T2* abnormality suggested that the two phenomenon were closely associated during the healing process. Our study demonstrates that quantitative T2 and T2* mapping techniques allow regional, longitudinal, and cross‐subject comparisons and give insights into histological and tissue remodeling processes. Such in vivo characterization will be important in grading severity and evaluating treatment strategies for myocardial infarction, potentially improving clinical outcomes. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.