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

Abstract

BackgroundA 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.MethodsTwenty-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.ResultsNative 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.ConclusionsT1-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.

Role of Cardiac Magnetic Resonance to Improve Risk Prediction following Acute ST-elevation Myocardial Infarction

“…Indeed, Garg et al demonstrated reliable determination of IS by parametric mapping, even indicating superior diagnostic accuracy of extracellular volume mapping as compared to LGE, which is limited by an overestimation of IS in the acute setting post-STEMI [67]. These results could be corroborated by Bulluck et al [68]; however, these small studies could not validate their findings for hard clinical events, which remains to be done by future studies. Compressed sensing has not only been investigated for accelerating cine CMR imaging but also shortening scan time of LGE imaging [69].…”

Cardiovascular Magnetic Resonance in Acute ST-Segment–Elevation Myocardial Infarction

“…Bulluck and colleagues 43 recently showed that post-contrast T1-mapping can accurately quantify acute MI size in a small group of STEMI patients, obviating the need to perform late gadolinium enhancement imaging. Recent studies have also investigated whether native T1-mapping (pre-contrast) can assess MI size.…”

Feasibility to Perform T2* Mapping Postcontrast Administration in Reperfused STEMI Patients for the Detection of Intramyocardial Hemorrhage

“…A comprehensive cardiac magnetic resonance imaging (MRI) scan takes about an hour. 7,8 This may be poorly tolerated by the acute STEMI patients. As IMH invariably occurs in areas of MVO (occurring in 50% of patients), 1 it may not be necessary to perform T 2 * mapping in those without MVO.…”