| Summary: | 碩士 === 國立陽明大學 === 放射醫學科學研究所 === 91 === Integration of myocardial fiber architecture and contractility of myocardium are correlated with cardiac function. The efficiency of cardiac function is directly affected by fiber arrangement of myocardium. The contractility of myocardium can be pretended by rate of deformation of myocardium.
In this thesis, we provide myocardial fiber architecture and mechanical function non-invasively and in vivo by using cardiac diffusion tensor imaging and strain rate magnetic resonance imaging in beating heart. The cardiac diffusion tensor imaging technique solved that myocardial structural information was obtained by anatomizing invasively in past. The strain rate magnetic resonance imaging technique provides higher resolution and precision in functional information of myocardium.
In our study, we successively applied two MR techniques in normal healthy adult, rugby football player and acute myocardial infarction patient. We found some unapproved or undiscovered results: we found general decrease in all strain rate components, but relative short in early relaxation period in athletes. In order to overcome much workload, athlete’s heart induced physiological adaptations, like myocardial fiber reorientation, to conquer higher wall stress and maintain normal cardiac function. In acute myocardial infarction patient, myocardial necrosis is due to ischemia, leading to the cellular breakdown of myocytes and increase in extracellular space, enhance diffusivity and increase trace apparent diffusion coefficient. The fractional anisotropy was also used to delineate the integration of local architecture.
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