ABSTRACT
Objective:To explore the technical feasibility of CT feature tracking (CT-FT) technique in evaluating left ventricular myocardial strain and evaluate the change of myocardial strain in patients with coronary heart disease.Methods:Eighty-one patients with coronary heart disease (lesion group) and 33 patients with normal coronary artery (control group) matched with age and sex were collected retrospectively from the Second Affiliated Hospital of Nanchang University from April 2019 to October 2020. The lesion group was first divided into single vessel stenosis group (42 cases) and multi vessel stenosis group (39 cases) according to the number of coronary artery stenosis branches, and the global myocardial strains of the left ventricle between the groups were analyzed. Lesion site included the left anterior descending branch (LAD), right coronary artery (RCA) and left circumflex branch (LCX), respectively. According to the degree of vascular stenosis, the lesion groups were divided into normal group, mild stenosis group, moderate stenosis group and severe stenosis group. The segmental myocardial strains of the branch segment of LAD, RCA or LCX were analyzed between groups. All CCTA examinations were performed with retrospective electrocardiogram gating. CVI 42 cardiac postprocessing software was used to obtain myocardial strain parameters, including global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS), and the segmental myocardial strains of the branch segment of LAD, RCA or LCX. The segmental myocardial strains included the peak longitudinal strain (PLS), peak circumferential strain (PCS) and peak radial strain (PRS). One way ANOVA or Kruskal Wallis H test were used for multi group analysis. Results:With the increased number of coronary artery stenosis branches, the absolute value of GPLS gradually decreased. The GPLS of the control group, single vessel stenosis group and multi vessel stenosis group were -14.1%±2.7%, -11.5%±2.3% and -8.8%±2.0%, respectively. The difference of GPLS between the 3 groups or any 2 groups was statistically significant (all P<0.001). The absolute values of GPRS and GPRS in multi vessel stenosis group were significantly lower than those in control group and single vessel stenosis group (all P<0.001). There was no significant difference in GPRS or GPRS between single vessel stenosis group and control group ( P=0.083, 0.118). And there were significant differences in the segmental myocardial strains of the branch segment of LAD, RCA or LCX among 3 groups ( P<0.001). In severe stenosis group, the absolute values of PRS, PCS and PLS in LAD, RCA or LCX were significantly lower than those in moderate stenosis group, mild stenosis group and normal group (all P<0.05). In the moderate stenosis group, the absolute value of PLS in each branch segment was lower than that of the mild stenosis and normal group (all P<0.05), and there was no significant difference in any 2 other myocardial strain parameters of each branch (all P>0.05). Conclusions:CT-FT technique was feasible to evaluate left ventricular myocardial function. With the increased number or degree of coronary artery stenosis, the global and segmental myocardial strain parameters of left ventricle gradually decreased, and the longitudinal strain was more sensitive.