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Magnetic resonance elastography as a method to estimate myocardial contractility
Author(s) -
Kolipaka Arunark,
Aggarwal Shivani R.,
McGee Kiaran P.,
Anavekar Nandan,
Manduca Armando,
Ehman Richard L.,
Araoz Philip A.
Publication year - 2012
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.23616
Subject(s) - magnetic resonance elastography , medicine , epinephrine , contractility , cardiology , stiffness , diastole , ultrasound , materials science , elastography , blood pressure , radiology , composite material
Purpose: To determine whether increasing epinephrine infusion in an in vivo pig model is associated with an increase in end‐systolic magnetic resonance elastography (MRE)‐derived effective stiffness. Materials and Methods: Finite element modeling (FEM) was performed to determine the range of myocardial wall thicknesses that could be used for analysis. Then MRE was performed on five pigs to measure the end‐systolic effective stiffness with epinephrine infusion. Epinephrine was continuously infused intravenously in each pig to increase the heart rate in increments of 20%. For each such increase end‐systolic effective stiffness was measured using MRE. In each pig, Student's t ‐test was used to compare effective end‐systolic stiffness at baseline and at initial infusion of epinephrine. Least‐square linear regression was performed to determine the correlation between normalized end‐systolic effective stiffness and increase in heart rate with epinephrine infusion. Results: FEM showed that phase gradient inversion could be performed on wall thickness ≈≥1.5 cm. In pigs, effective end‐systolic stiffness significantly increased from baseline to the first infusion in all pigs ( P = 0.047). A linear correlation was found between normalized effective end‐systolic stiffness and percent increase in heart rate by epinephrine infusion with R 2 ranging from 0.86–0.99 in four pigs. In one of the pigs the R 2 value was 0.1. A linear correlation with R 2 = 0.58 was found between normalized effective end‐systolic stiffness and percent increase in heart rate when pooling data points from all pigs. Conclusion: Noninvasive MRE‐derived end‐systolic effective myocardial stiffness may be a surrogate for myocardial contractility. J. Magn. Reson. Imaging 2012;36:120–127. © 2012 Wiley Periodicals, Inc.