Application Value of Coronary CTA Combined with CMR T1 Mapping in Evaluating Salvable Myocardium in Patients with STEMI

Objective:Coronary angiography(CTA) and magnetic resonance longitudinal relaxation time quantification(T1 mapping) imaging were used to evaluate the level of vascular reflow after myocardial ischemia and the salvage degree of myocardial reperfusion injury in patients with STEMI. Methods:Thirty patients with STEMI diagnosed clinically(experimental group) and 20 healthy persons who met the inclusion criteria(normal control group) were collected. In the experimental group, coronary CTA and T1 mapping sequence were performed. The level of vascular reflow was evaluated by CTA. The volume of area at risk and myocardial salvage index were measured quantitatively by T1 mapping. The T1 values of different segments of myocardium in the experimental group and the control group were calculated and statistically analyzed. Results:Coronary CTA showed reflow of all LAD, LCX, RCA responsible vessels in the experimental group, and T1 mapping showed that the area at risk of STEMI patients was 30.2 ±8.8(%LV), myocardial core infarction 4.7 ±1.7(%LV), and the myocardial salvage index was 67 ±16%. STEMI patients T1_AAR value(1395 ±108 ms) > T1_remote value(1062 ±93 ms) > T1_NC value(967 ±78 ms)(P < 0.05). However, there was no significant difference in the average T1 value of myocardial segments dominated by the three responsible vessels in the experimental group(P=0.79). Conclusion:Coronary CTA technique and CMR T1 mapping sequence can comprehensively and quantitatively evaluate the salvage degree of myocardial ischemia-reperfusion injury in patients with STEMI, and provide imaging support for clinic.