Automatic evaluation of left ventricular systolic function in rats with myocardial infarction by myocardial contrast echocardiography based on neutrosophic similarity score algorithm

Objective To evaluate the accuracy and value of automatically assessing left ventricular systolic function in rats with myocardial infarction (MI) by myocardial contrast echocardiography (MCE) based on neutrosophic similarity score(NSS) algorithm. Methods According to different infarction size(IS), SD rats were divided into large MI (MI-L, IS≥15%) and small MI (MI-S, IS<15%) groups. MCE was performed before MI and at 7, 28 days after MI. In vitro study: the automatic segmentation of the endocardial contour based on neutrosophic similarity score algorithm was compared with the manual segmentation boundary. In vivo study: the left ventricular ejection fraction(LVEF) were calculated using the NSS system, biplane Simpson and PV-loop, respectively, and then NSS-LVEF, Simpson-LVEF and PV-LVEF were acquired, respectively. The IS was calculated by Masson and HE staining. The consistency between the two LVEFs was evaluated by Bland-Altman. The intraclass correlation coefficient (ICC) was calculated to evaluate the reproducibility of MCE analysis system. Results ①The endocardial contour obtained by automatic segmentation had good agreement with the boundary of artificial tracing. ②There was no significant difference among the three LVEFs in same group (F=0.028, P=0.973), but there was significant difference in different group (F=78.61, P<0.01). NSS-LVEF was well consistent with both Simpson-LVEF and PV-LVEF. ③The ICC of NSS algorithm for inter-observer and intra-observer were 0.96 and 0.98, respectively. ④Compared with before MI and at 7 days after MI, the LVEF in MI-L and MI-S groups at 28 days after MI decreased significantly (P<0.05), especially in MI-L group (P<0.01). There was significantly negative correlation between LVEF and IS (r=-0.917, P<0.01). Conclusions Left ventricular endocardium can be identificated automatically and LVEF can be calculated rapidly and accurately by MCE based on neutrosophic similarity score algorithm in rats with myocardial infarction. Key words: Echocardiography; Myocardial contrast echocardiography; Myocardial infarction; Ventricular function, left; Image processing, neutrosophic similarity score, computer-aided; Rat