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

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Mohammad Alkhalil ◽  
◽  
Alessandra Borlotti ◽  
Giovanni Luigi De Maria ◽  
Mathias Wolfrum ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Infarct Size ◽  
Myocardial Injury ◽  
T1 Mapping ◽  
Characteristic Analysis ◽  
Area At Risk ◽  
Severity Of Injury ◽  
Final Infarct Size

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 cut-off 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.

Abstract 14877: Native T1-based Cardiovascular Magnetic Resonance for Characterizing Chronic Myocardial Infarctions: Proof-of-Concept Study in Canines

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Avinash Kali ◽  
Ivan Cokic ◽  
Richard L Tang ◽  
Hsin J Yang ◽  
Behzad Sharif ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Infarct Size ◽  
T1 Mapping ◽  
Ischemia Reperfusion Injury ◽  
Ex Vivo ◽  
Ischemia Reperfusion ◽  
Infarcted Myocardium ◽  
Native T1 ◽  
Replacement Fibrosis

Introduction: Gadolinium infusion required for Late Gadolinium Enhancement (LGE) Cardiovascular Magnetic Resonance (CMR) imaging is contraindicated in nearly 20% of myocardial infarction (MI) patients due to chronic end-stage kidney disease. Hypothesis: Using a canine model of MI, we investigated whether native T1 mapping at 3T could be an alternative to LGE CMR for characterizing chronic MIs (CMIs). Methods: Canines (n=29) were subjected to ischemia-reperfusion injury. Native T1 maps, native T2 maps and LGE images were acquired at 7 days (acute, AMI) and 4 months (CMI) post-MI at 1.5T and 3T. Infarct location, size and transmurality, measured using Mean + 5 Standard Deviations criterion, were compared between T1 maps and LGE images. Native T2 maps were used to examine the resolution of edema between AMI and CMI. Following the CMR studies, animals were euthanized and ex-vivo histology was performed. Results: T1 maps and LGE images were not different for measuring infarct size (p=0.61) and transmurality (p=0.81) in CMI at 3T. In AMI at 3T, T1 maps overestimated both infarct size (p=0.007) and transmurality (p=0.007) relative to LGE images. At 1.5T, T1 maps underestimated both infarct size and transmurality relative to LGE images in both AMI and CMI (p<0.001 for all cases). Relative to the remote territories, T1 of the infarcted myocardium was elevated in AMI (3T: p<0.001; 1.5T: p<0.001) and CMI (3T: p<0.001; 1.5T: p=0.037). T2 of the infarcted myocardium was elevated in AMI (p<0.001 at both 3T and 1.5T), but not in CMI (3T: p=0.19, 1.5T: p=0.55) indicating that myocardial edema resolved by 4 months post-MI. Masson’s trichrome staining showed extensive replacement fibrosis within CMIs. Sensitivity and specificity of T1 maps to detect CMI were 95% and 97% respectively at 3T, and 58% and 78% respectively at 1.5T. Conclusions: Native T1 mapping at 3T can characterize CMIs with high diagnostic accuracy. T1 elongations in CMI appear to arise predominantly from replacement fibrosis.

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