The research of myocardial fibers character in isolated rats heart based on 7.0 T diffusion tensor ;imaging / 中华放射学杂志

ABSTRACT

Objective Using 7.0 T diffusion tensor imaging(DTI) to study myocardial fibers character in isolated rats heart in aspect of water molecular diffusion, myocardial mechanics and microstructure. Methods Fixed male rats heart (n=10) underwent DTI and the myocardial structures were quantitatively measured by Diffusion Toolkit and Matlab. The characteristic of myocardial fibers arrangement was observed and FA values and ADC values of myocardial fibers, myocardial fibers density and length, mean helix angle of left ventricular were calculated as well. Mean helix angle of anterior wall, ventricular septum, lateral wall and posterior wall of epicardium and endocardium were compared by using one?way ANOVA. Results The SD rats' myocardial fibers appeared in compact and inerratic distribution from epicardium to endocardium. Compared with HE staining, regular direction and arrangement in fibers were showed in myocardial fibers tracer map and tensor map in papillary muscle plane. Quantitative analysis showed that ADC value of SD rats' myocardial fibers was (9.6 ± 3.6) × 10-4 mm2/s, FA value was 0.80 ± 0.04, myocardial fibers density was (981±24) tracks/mm3 and myocardial fibers length was (6.18±1.71)mm. Mean helix angle of left ventricular epicardium to endocardium ranged from-81.37° to 0° and then gradually change to 82.83° . There were no significant differences in mean helix angle of anterior wall, ventricular septum, lateral wall and posterior wall of epicardium and endocardium, respectively (F=2.25, 0.40, P>0.05). Conclusions This study shows that DTI is an effective method to quantitatively measure the characteristics of myocardial fibers. This study provides useful information for further study of myocardial fibers in heart disease models.