Hyper-acute cardiovascular magnetic resonance T1 mapping predicts infarct characteristics in patients with ST elevation myocardial infarction

Abstract

Background: Myocardial recovery after primary percutaneous coronary intervention in acute myocardial infarction is variable and the extent and severity of injury are difficult to predict. We sought to investigate the role of cardiovascular magnetic resonance T1 mapping in the determination of myocardial injury very early after treatment of ST-segment elevation myocardial infarction (STEMI). Methods: STEMI patients underwent 3 T cardiovascular magnetic resonance (CMR), within 3 h of primary percutaneous intervention (PPCI). T1 mapping determined the extent (area-at-risk as %left ventricle, AAR) and severity (average T1 values of AAR) of acute myocardial injury, and related these to late gadolinium enhancement (LGE), and microvascular obstruction (MVO). The characteristics of myocardial injury within 3 h was compared with changes at 24-h to predict final infarct size. Results: Forty patients were included in this study. Patients with average T1 values of AAR ≥1400 ms within 3 h of PPCI had larger LGE at 24-h (33% ±14 vs. 18% ±10, P = 0.003) and at 6-months (27% ±9 vs. 12% ±9; P < 0.001), higher incidence and larger extent of MVO (85% vs. 40%, P = 0.016) & [4.0 (0.5-9.5)% vs. 0 (0-3.0)%, P = 0.025]. The average T1 value was an independent predictor of acute LGE (β 0.61, 95%CI 0.13 to 1.09; P = 0.015), extent of MVO (β 0.22, 95%CI 0.03 to 0.41, P = 0.028) and final infarct size (β 0.63, 95%CI 0.21 to 1.05; P = 0.005). Receiver-operating-characteristic analysis showed that T1 value of AAR obtained within 3-h, but not at 24-h, predicted large infarct size (LGE > 9.5%) with 100% positive predictive value at the optimal cutoff of 1400 ms (area-under-the-curve, AUC 0.88, P = 0.006). Conclusion: Hyper-acute T1 values of the AAR (within 3 h post PPCI, but not 24 h) predict a larger extent of MVO and infarct size at both 24 h and 6 months follow-up. Delayed CMR scanning for 24 h could not substitute the significant value of hyper-acute average T1 in determining infarct characteristics.

Imaging tools for assessment of myocardial fibrosis in humans: the need for greater detail

“…All of these are central to appropriate risk stratification and prognostication of patients at a very early stage of the disease (Aherne 2012;Vanessa et al 2012;Liu et al 2017;Alkhalil et al 2020). The ability to stratify patients early in the disease course allows appropriate patient recruitment for clinical trials to precisely assess the effectiveness of new interventions.…”

“…Post gadolinium T 1 maps permit measurement of the infarction size and transmurality (Liu et al 2017;Perez-Terol et al 2019;Alkhalil et al 2020). Furthermore, extracellular volume (ECV) fraction maps can be extrapolated from these, which reflect the increased extracellular edema and fibrosis correlating histologically with increased collagen deposition (Flett 2010) taking into account that the calculation of ECV relies on the difference between precontrast and postcontrast T1 relaxation times and on hematocrit (Lurz et al 2016;Radunski et al 2017).…”

Coronary revascularization in patients with left ventricle systolic dysfunction, current challenges and clinical outcomes

“…The main advantage of CMRI in viability assessment is demonstrating both anatomical contractile recovery akin to stress echocardiography and tissue characterization with delayed contrast enhancement. CMRI assessment has also great resolution in comparison to other techniques, however, the presence of late gadolinium enhancement (LGE) does not necessitate non-viable myocardium, particularly in the early days after myocardial infarction [32,33]. Emerging technique such as T1 mapping would have advantages over LGE in predicting infarct characteristics and establishing viability in the early stages following MI without the need for contrast agents [32,34].…”

“…An interaction between long term outcomes and viability was evaluated in patients who underwent CABG plus medical therapy or medical therapy alone (Table 1, Ref. [32]) [38]. Regardless of the treatment strategy, patients with viable myocardium had significantly lower mortality rate compared to patients without viable myocardium (37% versus 51%; HR 0.64, 95% CI 0.48 to 0.86) [38] (Table 1).…”

CMR Parametric Mapping as a Tool for Myocardial Tissue Characterization

“…The biggest advantage of native T1-mapping is myocardial tissue characterization without the need for contrast agents. It readily detects changes in acute myocardial infarction, 16) 22) 23) 24) 25) acute myocarditis, 4) 15) and cardiac amyloidosis 17) 26) 27) 28) —these typically lead to very high native T1 values ( Figures 4 and 5 ). 17) 29) In cardiomyopathies, T1-mapping have been shown to detect abnormalities not detectable by LGE, such as in dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM), in which “apparently-normal” myocardial segments with normal wall thickness and without LGE also demonstrate abnormally increased T1 values ( Figure 6 ).…”