title: MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model.
abstract: This study aimed to investigate postinfarct left ventricular (LV) fiber structural alterations by ex vivo diffusion tensor imaging (DTI) in a porcine heart model. In vivo cardiac MR imaging was first performed to measure ventricular function in six adult pigs with septal infarction near apex induced by the LAD ligation 13 weeks earlier. Hearts were then excised from the infarct pigs (n = 6) and six intact controls (n = 6) and fixed in formalin. High-resolution DTI was employed to examine changes in fractional anisotropy (FA), apparent diffusion coefficient (ADC), and transmural helix angle distribution in the infarct, adjacent and remote regions as compared to the sham regions in the controls. FA values were found to decrease in the infarct and differ between the adjacent and remote regions. ADC increase in the infarct region was substantial, while changes in the adjacent and remote regions were insignificant. Structurally, the double-helix myocardial structure shifted toward more left-handed around the infarcted myocardium. Accordingly, the histological analysis revealed clear fiber structural degradation in the adjacent region. These findings confirmed the subtle alterations in the myocardial fiber quality and structure not only in the infarcted but also in the surrounding noninfarcted myocardium or borderzone.
authors: Laboratory of Biomedical Imaging and Signal Processing, University of Hong Kong, Hong Kong. ewu@eee.hku.hk
authors: Ed X
authors: EX
authors: Wu
authors: Yin
authors: Y
authors: Wu
authors: John M
authors: JM
authors: Nicholls
authors: Jie
authors: J
authors: Wang
authors: Songyan
authors: S
authors: Liao
authors: Shuguang
authors: S
authors: Zhu
authors: Chu-Pak
authors: CP
authors: Lau
authors: Hung-Fat
authors: HF
authors: Tse
mesh_terms: D000818:Animals; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D009203:Myocardial Infarction / Q000473:pathology*; D013552:Swine; D013556:Swine, Miniature; D020257:Ventricular Remodeling / Q000502:physiology*