Quantification of both the area-at-risk and acute myocardial infarct size in ST-segment elevation myocardial infarction using T1-mapping

Background: a comprehensive cardiovascular magnetic resonance (cmr) in reperfused st-segment myocardial infarction (stemi) patients can be challenging to perform and can be time-consuming. we aimed to investigate whether native t1-mapping can accurately delineate the edema-based area-at-risk (aar) and post-contrast t1-mapping and synthetic late gadolinium (lge) images can quantify mi size at 1.5 t. conventional lge imaging and t2-mapping could then be omitted,thereby shortening the scan duration. methods: twenty-eight stemi patients underwent a cmr scan at 1.5 t,3 ± 1 days following primary percutaneous coronary intervention. the aar was quantified using both native t1 and t2-mapping. mi size was quantified using conventional lge,post-contrast t1-mapping and synthetic magnitude-reconstructed inversion recovery (magir) lge and synthetic phase-sensitive inversion recovery (psir) lge,derived from the post-contrast t1 maps. results: native t1-mapping performed as well as t2-mapping in delineating the aar (41.6 ± 11.9% of the left ventricle [% lv] versus 41.7 ± 12.2% lv,p = 0.72; r2 0.97; icc 0.986 (0.969-0.993); bias -0.1 ± 4.2% lv). there were excellent correlation and inter-method agreement with no bias,between mi size by conventional lge,synthetic magir lge (bias 0.2 ± 2.2%lv,p = 0.35),synthetic psir lge (bias 0.4 ± 2.2% lv,p = 0.060) and post-contrast t1-mapping (bias 0.3 ± 1.8% lv,p = 0.10). the mean scan duration was 58 ± 4 min. not performing t2 mapping (6 ± 1 min) and conventional lge (10 ± 1 min) would shorten the cmr study by 15-20 min. conclusions: t1-mapping can accurately quantify both the edema-based aar (using native t1 maps) and acute mi size (using post-contrast t1 maps) in stemi patients without major cardiovascular risk factors. this approach would shorten the duration of a comprehensive cmr study without significantly compromising on data acquisition and would obviate the need to perform t2 maps and lge imaging. © 2017 the author(s).