Diagnostic performance of T1 and T2 mapping to detect intramyocardial hemorrhage in reperfused ST-segment elevation myocardial infarction (STEMI) patients

Abstract

Purpose: To investigate the performance of T₁ and T₂ mapping to detect intramyocardial hemorrhage (IMH) in ST-segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention (PPCI).

Materials and methods: Fifty STEMI patients were prospectively recruited between August 2013 and July 2014 following informed consent. Forty-eight patients completed a 1.5T cardiac magnetic resonance imaging (MRI) with native T₁ , T₂ , and T2* maps at 4 ± 2 days. Receiver operating characteristic (ROC) analyses were performed to assess the performance of T₁ and T₂ to detect IMH.

Results: The mean age was 59 ± 13 years old and 88% (24/48) were male. In all, 39 patients had interpretable T2* maps and 26/39 (67%) of the patients had IMH ( T2* <20 msec on T2* maps). Both T₁ and T₂ values of the hypointense core within the area-at-risk (AAR) performed equally well to detect IMH (T₁ maps AUC 0.86 [95% confidence interval [CI] 0.72-0.99] versus T₂ maps AUC 0.86 [95% CI 0.74-0.99]; P = 0.94). Using the binary assessment of presence or absence of a hypointense core on the maps, the diagnostic performance of T₁ and T₂ remained equally good (T₁ AUC 0.87 [95% CI 0.73-1.00] versus T₂ AUC 0.85 [95% CI 0.71-0.99]; P = 0.90) with good sensitivity and specificity (T₁ : 88% and 85% and T₂ : 85% and 85%, respectively).

Conclusion: The presence of a hypointense core on the T₁ and T₂ maps can detect IMH equally well and with good sensitivity and specificity in reperfused STEMI patients and could be used as an alternative when T2* images are not acquired or are not interpretable.

Level of evidence: 2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:877-886.

Keywords: T2* mapping; ST-segment elevation myocardial infarction; T1 mapping; T2 mapping; intramyocardial hemorrhage; microvascular obstruction.

Figure 1

Semiautomated method used to identify the hypointense core on the T ₁ and T ₂ maps.

Figure 2

Example of a patient with an acute inferior MI depicting the evidence of MVO on EGE and LGE scans with corresponding hypointense cores (red and black arrows) on the basal LV short axis $T_2^{*}$, T ₁, and T ₂ maps.

Figure 3

Details of the screening and recruitment of patients entering this study.

Figure 4

T ₁ and T ₂ values of the hypointense core, remote myocardium, and the salvaged myocardium. *Statistically significant difference.

Figure 5

ROC curves for the diagnostic performance of T ₁ and T ₂ mapping to detect IMH on the acute scans when compared to $T_2^{*}$ maps