Value of cardiovascular MR tissue-tracking imaging in the quantitative evaluation of myocardial strain after myocardial infarction / 中华放射学杂志

ABSTRACT

Objective@#To investigate the application value of cardiovascular magnetic resonance tissue-tracking (CMR-TT) in the quantitative assessment of global and segmental myocardial strain after myocardial infarction.@*Methods@#From June 2013 to June 2017, 45 patients with chronic myocardial infarction from the Second Affiliated Hospital of Nanchang University and eighteen normal volunteers as a control group were included in our research. All participants received CMR examination on a 3.0 T MRI scanner. Imaging protocol including FIESTA cine sequence (left ventricle short-axis planes, four chamber and two chamber long-axis planes) and late gadolinium enhancement (LGE). CMR-TT was undertaken using cvi 42 dedicated commercial software, global peak systolic circumferential, longitudinal, radial strains (GPCS, GPLS, GPRS) and segmental peak systolic circumferential, longitudinal, radial strains (PCS, PLS, PRS) in accordance with the American Heart Association's sixteen segment model were all derived. All segments were divided into five groups according to transmural extent expressed as enhanced area per segment: 0% as non-LGE segments group, 1 %-25 % as mild LGE segments group, 26%-50 % as moderate LGE segments group, 51%-75% as severe LGE segments group and >75% as complete LGE segments group. Two-independent samples t-test and Kruskal-Wallis H test were used, respectively, to compare means of 2 and 3 or more groups of continuous variables. Variables with normal distribution were presented as ±s, non-normal variables were reported as median (interquartile range).@*Results@#Patients showed significant lower GPRS, GPCS and GPLS than the control group (15.13%±8.18%, -8.25%±3.23%, -7.11%±2.41% versus 32.41%±12.99%, -14.92%±3.32%, -11.50%±2.51%). PRS, PCS and PLS statistically significantly decreased with increasing extent of myocardial enhancement (t=-6.35,7.33,6.44, P<0.001).Segmental peak systolic strains of five groups were:PRS:24.87% (10.95%,39.02%), 13.26%(5.94%,24.24)%, 9.47%(4.01%,18.40%), 5.98%(-3.74%,11.86%), -2.65%(-6.62%,8.59%), respectively; PCS: -11.84%±5.34%, -8.60%±5.48%, -7.32%±5.59%, -5.30%±5.52%, -2.74%±5.24%, respectively; PLS: -9.47%±6.82%, -7.72%±6.22%, -7.07%±6.49%, -5.55%±5.95%, -3.54%±5.44%, respectively. The differences in the groups were statistically significant (H=164.47,166.61, 59.06, P<0.001). GPRS was positively correlated with LVEF(r=0.543, P<0.001), while GPCS and GPLS were both negatively associated with LVEF (r=-0.654, P<0.001; r=-0.682, P<0.001, respectively).@*Conclusions@#CMR-TT can quantitatively assess the severity of myocardial infarction accurately and reliably.Strain parameters have a good correlation with cardiac function indexes, this may be helpful in the recognition of left ventricular remodel after MI.