Measurement of myocardial mechanics in mice before and after infarction using multislice displacement-encoded MRI with 3D motion encoding

• Published in: American journal of physiology. Heart and circulatory physiology 2005-03, Vol.288 (3), p.H1491-H1497
• Main Authors: Gilson, Wesley D, Yang, Zequan, French, Brent A, Epstein, Frederick H
• Format: Article
• Language: English
• Subjects: Animals; Heart - physiology; Imaging, Three-Dimensional - methods; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Male; Mice; Mice, Inbred C57BL; Myocardial Contraction - physiology; Ventricular Function, Left - physiology
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00632.2004

Departments of 1 Biomedical Engineering, 2 Radiology and the 3 Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia Submitted 24 June 2004 ; accepted in final form 22 October 2004 Cardiac MRI is an accurate, noninvasive modality for assessing the structure and function of the murine heart. In addition to conventional imaging, MRI tissue tracking methods can quantify numerous aspects of myocardial mechanics, including intramyocardial displacement, strain, twist, and torsion. In the present study, we developed and applied a novel pulse sequence based on displacement-encoded imaging using stimulated echoes (DENSE) that achieves multislice coverage, high spatial resolution, and three-dimensional (3D) displacement encoding. With the use of this technique, myocardial mechanics of C57Bl/6 mice were measured at baseline and 1 day after experimental myocardial infarction. At baseline, the mean systolic transmural circumferential strain was –0.14 ± 0.02 and the mean systolic radial strain was 0.30 ± 0.05. Changes in circumferential and radial strains from the subepicardium to the subendocardium were detected at baseline ( P < 0.05). One day after infarction, significantly reduced 3D displacements and strain were detected in infarcted and noninfarcted myocardium. Infarction also reduced normalized systolic torsion from its baseline value of 1.35 ± 0.27°/mm ( R = 0.99) to 0.07 ± 0.54°/mm ( R = 0.96, P < 0.05). DENSE MRI can assess the 3D myocardial mechanics of the murine heart in