Correlation of 3D DT-MRI Fiber Disruption with Structural and Mechanical Degeneration in Porcine Myocardium

• Published in: Annals of biomedical engineering 2010-10, Vol.38 (10), p.3084-3095
• Main Authors: Zhang, Song, Crow, J. Allen, Yang, Xiaoyong, Chen, Joseph, Borazjani, Ali, Mullins, Katie B, Chen, Wei, Cooper, Robert C, McLaughlin, Ronald M, Liao, Jun
• Format: Article
• Language: English
• Subjects: 3D myocardial fiber disruption; Animals; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Biophysics; Cardiac biomechanics; Classical Mechanics; Clustering model; Diffusion Tensor Imaging - methods; Diffusion tensor MRI; Disease Models, Animal; Fiber tracks; Heart - diagnostic imaging; Humans; Imaging, Three-Dimensional - methods; Myocardial infarction; Myocardial Infarction - diagnostic imaging; Myocardium; Radiography; Swine
• ISSN: 0090-6964; 1573-9686
• DOI: 10.1007/s10439-010-0073-8

Evaluation of structural parameters following a myocardial infarction (MI) is important to assess left ventricular function and remodeling. In this study, we assessed the capability of 3D diffusion tensor magnetic resonance imaging (DT-MRI) to assess tissue degeneration shortly after an MI using a porcine model of infarction. Two days after an induced infarction, hearts were explanted and immediately scanned by a 3T MRI scanner with a diffusion tensor imaging protocol. 3D fiber tracks and clustering models were generated from the diffusion-weighted imaging data. We found in a normal explanted heart that DT-MRI fibers showed a multilayered helical structure, with fiber architecture and fiber density reflecting the integrity of muscle fibers. For infarcted heart explants, we observed either a lack of fibers or disruption of fibers in the infarcted regions. Contours of the disrupted DT-MRI fibers were found to be consistent with the infarcted regions. Both histological and mechanical analysis of the infarcted hearts suggested DT-MRI fiber disruption correlated with altered microstructure and tissue mechanics. The ability of 3D DT-MRI to accurately distinguish viable myocardium from dead myocardium only 2 days post infarct without the use of radioisotopes or ionotropic agents makes it a promising approach to evaluate cardiac damage early post-MI.