title: Remodeling of cardiac fiber structure after infarction in rats quantified with diffusion tensor MRI.
abstract: Structural remodeling of myocardium after infarction plays a critical role in functional adaptation. Diffusion tensor magnetic resonance imaging (DTMRI) provides a means for rapid and nondestructive characterization of the three-dimensional fiber architecture of cardiac tissues. In this study, microscopic structural changes caused by MI were evaluated in Fischer 344 rats 4 wk after infarct surgery. DTMRI studies were performed on 15 excised, formalin-fixed rat hearts of both infarct (left anterior descending coronary artery occlusion, n = 8) and control (sham, n = 7) rats. Infarct myocardium exhibited increased water diffusivity (41% increase in trace values) and decreased diffusion anisotropy (37% decrease in relative anisotropy index). The reduced diffusion anisotropy correlated negatively with microscopic fiber disarray determined by histological analysis (R = 0.81). Transmural courses of fiber orientation angles in infarct zones were similar to those of normal myocardium. However, regional angular deviation of the diffusion tensor increased significantly in the infarct myocardium and correlated strongly with microscopic fiber disarray (R = 0.86). These results suggest that DTMRI may provide a valuable tool for defining structural remodeling in diseased myocardium at the cellular and tissue level.
authors.affiliation: Cardiovascular Magnetic Resonance Laboratories, Cardiovascular Division, Department of Medicine, Washington University, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
authors.forename: Junjie
authors.initials: J
authors.lastname: Chen
authors.forename: Sheng-Kwei
authors.initials: SK
authors.lastname: Song
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Mark
authors.initials: M
authors.lastname: McLean
authors.forename: J Stacy
authors.initials: JS
authors.lastname: Allen
authors.forename: Jie
authors.initials: J
authors.lastname: Tan
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Wickline
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
mesh_terms: D000818:Animals; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006352:Heart Ventricles / Q000473:pathology; D009203:Myocardial Infarction / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344; D020257:Ventricular Remodeling; D014867:Water
chemical_list: D014867:Water