Diagnostic Accuracy of 3.0-T Magnetic Resonance T1 and T2 Mapping and T2-Weighted Dark-Blood Imaging for the Infarct-Related Coronary Artery in Non-ST-Segment Elevation Myocardial Infarction

Background-Patients with recent non-ST-segment elevation myocardial infarction commonly have heterogeneous characteristics that may be challenging to assess clinically. Methods and Results-We prospectively studied the diagnostic accuracy of 2 novel (T1, T2 mapping) and 1 established (T2-weighted short tau inversion recovery [ T2W-STIR]) magnetic resonance imaging methods for imaging the ischemic area at risk and myocardial salvage in 73 patients with non-ST-segment elevation myocardial infarction (mean age 57 +/- 10 years, 78% male) at 3.0-T magnetic resonance imaging within 6.5 +/- 3.5 days of invasive management. The infarct-related territory was identified independently using a combination of angiographic, ECG, and clinical findings. The presence and extent of infarction was assessed with late gadolinium enhancement imaging (gadobutrol, 0.1 mmol/kg). The extent of acutely injured myocardium was independently assessed with native T1, T2, and T2W-STIR methods. The mean infarct size was 5.9 +/- 8.0% of left ventricular mass. The infarct zone T1 and T2 times were 1323 +/- 68 and 57 +/- 5 ms, respectively. The diagnostic accuracies of T1 and T2 mapping for identification of the infarct-related artery were similar (P=0.125), and both were superior to T2W-STIR (P < 0.001). The extent of myocardial injury (percentage of left ventricular volume) estimated with T1 (15.8 +/- 10.6%) and T2 maps (16.0 +/- 11.8%) was similar (P=0.838) and moderately well correlated (r=0.82, P < 0.001). Mean extent of acute injury estimated with T2W-STIR (7.8 +/- 11.6%) was lower than that estimated with T1 (P < 0.001) or T2 maps (P < 0.001). Conclusions-In patients with non-ST-segment elevation myocardial infarction, T1 and T2 magnetic resonance imaging mapping have higher diagnostic performance than T2W-STIR for identifying the infarct-related artery. Compared with conventional STIR, T1 and T2 maps have superior value to inform diagnosis and revascularization planning in non-ST-segment elevation myocardial infarction.