Fiber architecture in remodeled myocardium revealed with a quantitative diffusion CMR tractography framework and histological validation

Journal of Cardiovascular Magnetic Resonance

Research

William J Kostis¹  David E Sosnovik²  Howard H Chen³  Guangping Dai³  Timothy G Reese³  Choukri Mekkaoui³  Shuning Huang³  Jeremy N Ruskin⁴  Aravinda Thiagalingam⁴  Marcel P Jackowski⁵  Udo Hoffmann⁶  Pal Maurovich-Horvat⁶ 

[1] Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA;Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA;Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA;Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA;Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA;Athinoula A. Martinos Center For Biomedical Imaging, 149 13th Street, 02129, Charlestown, MA, USA;Athinoula A. Martinos Center For Biomedical Imaging, Boston, MA, USA;Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA;Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA;Department of Computer Science, Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil;Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA;

关键词: Diffusion tensor imaging;    Tractography;    Myocardium;    Remodeling;    Heart;   

DOI  :  10.1186/1532-429X-14-70

 received in 2012-05-22, accepted in 2012-10-01,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe study of myofiber reorganization in the remote zone after myocardial infarction has been performed in 2D. Microstructural reorganization in remodeled hearts, however, can only be fully appreciated by considering myofibers as continuous 3D entities. The aim of this study was therefore to develop a technique for quantitative 3D diffusion CMR tractography of the heart, and to apply this method to quantify fiber architecture in the remote zone of remodeled hearts.MethodsDiffusion Tensor CMR of normal human, sheep, and rat hearts, as well as infarcted sheep hearts was performed ex vivo. Fiber tracts were generated with a fourth-order Runge-Kutta integration technique and classified statistically by the median, mean, maximum, or minimum helix angle (HA) along the tract. An index of tract coherence was derived from the relationship between these HA statistics. Histological validation was performed using phase-contrast microscopy.ResultsIn normal hearts, the subendocardial and subepicardial myofibers had a positive and negative HA, respectively, forming a symmetric distribution around the midmyocardium. However, in the remote zone of the infarcted hearts, a significant positive shift in HA was observed. The ratio between negative and positive HA variance was reduced from 0.96 ± 0.16 in normal hearts to 0.22 ± 0.08 in the remote zone of the remodeled hearts (p<0.05). This was confirmed histologically by the reduction of HA in the subepicardium from −52.03° ± 2.94° in normal hearts to −37.48° ± 4.05° in the remote zone of the remodeled hearts (p < 0.05).ConclusionsA significant reorganization of the 3D fiber continuum is observed in the remote zone of remodeled hearts. The positive (rightward) shift in HA in the remote zone is greatest in the subepicardium, but involves all layers of the myocardium. Tractography-based quantification, performed here for the first time in remodeled hearts, may provide a framework for assessing regional changes in the left ventricle following infarction.

【 授权许可】

Unknown   
© Mekkaoui et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.