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Principal strain orientation in the normal human left ventricle
Brian P Cupps1, Benjamin J Pomerantz, Marc D Krock
1Department of Surgery, Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
The Annals of Thoracic Surgery
|March 31, 2005
Summary
This study characterizes normal myocardial contraction patterns using magnetic resonance imaging (MRI) with tissue tagging. Findings establish baseline principal strain angles, crucial for detecting ischemia in coronary artery disease patients.
Area of Science:
- Cardiovascular imaging
- Biomechanical analysis
- Myocardial strain quantification
Background:
- Accurate directed interventions for coronary artery disease require improved methods.
- Magnetic resonance imaging (MRI) with tissue tagging offers noninvasive, quantitative strain analysis.
- Minimum principal strain vector direction is sensitive to myocardial ischemia.
Purpose of the Study:
- To fully characterize the normal range of minimum principal strain vector direction in the in vivo human left ventricle.
- To assess these ranges at rest and during dobutamine-induced inotropic stimulation.
Main Methods:
- Acquired tagged MRI data from 20 healthy volunteers at rest and during dobutamine infusion.
- Computed strain using finite element software from displacement data.
- Measured the principal strain angle between the minimum principal strain vector and the circumferential-longitudinal plane in 6 ventricular regions and globally.
Main Results:
- Resting principal strain angles were small, indicating normal myocardial contraction occurs mainly in the circumferential-longitudinal plane.
- Principal strain angles remained similar during dobutamine infusion.
- No significant regional differences in principal strain angles were observed at rest or during dobutamine infusion.
Conclusions:
- The direction of maximal myocardial contraction shifts with ischemic injury, serving as a sensitive index of myocardial ischemia.
- Accurate characterization of normal principal strain angle ranges is essential for clinical application of this technology.