Displacement Encoding With Stimulated Echoes Enables the Identification of Infarct Transmurality Early Postmyocardial Infarction

Abstract

Background: Segmental extent of infarction assessed by late gadolinium enhancement (LGE) imaging early post-ST-segment elevation myocardial infarction (STEMI) has utility in predicting left ventricular functional recovery.

Hypothesis: We hypothesized that segmental circumferential strain with displacement encoding with stimulated echoes (DENSE) would be a stronger predictor of infarct transmurality than feature-tracking strain, and noninferior to extracellular volume fraction (ECV).

Study type: Prospective.

Population: Fifty participants (mean ± SD, 59 ± 9 years, 40 [80%] male) underwent cardiac MRI on day 1 post-STEMI.

Field-strength/sequences: 1.5T/cine, DENSE, T₁ mapping, ECV, LGE.

Assessment: Two observers assessed segmental percentage LGE extent, presence of microvascular obstruction (MVO), circumferential and radial strain with DENSE and feature-tracking, T₁ relaxation times, and ECV.

Statistical tests: Normality was tested using the Shapiro-Wilk test. Skewed distributions were analyzed utilizing Mann-Whitney or Kruskal-Wallis tests and normal distributed data using independent t-tests. Diagnostic cutoff values were identified using the Youden index. The difference in area under the curve was compared using the z-statistic.

Results: Segmental circumferential strain with DENSE was associated with the extent of infarction ≥50% (AUC [95% CI], cutoff value = 0.9 [0.8, 0.9], -10%) similar to ECV (AUC = 0.8 [0.8, 0.9], 37%) (P = 0.117) and superior to feature-tracking circumferential strain (AUC = 0.7[0.7, 0.8], -19%) (P < 0.05). For the detection of segmental infarction ≥75%, circumferential strain with DENSE (AUC = 0.9 [0.8, 0.9], -10%) was noninferior to ECV (AUC = 0.8 [0.7, 0.9], 42%) (P = 0.132) and superior to feature-tracking (AUC = 0.7 [0.7, 0.8], -13%) (P < 0.05). For MVO detection, circumferential strain with DENSE (AUC = 0.8 [0.8, 0.9], -12%) was superior to ECV (AUC = 0.8 [0.7, 0.8] 34%) (P < 0.05) and feature-tracking (AUC = 0.7 [0.6, 0.7] -21%) (P < 0.05).

Data conclusion: Circumferential strain with DENSE is a functional measure of infarct severity and may remove the need for gadolinium contrast agents in some circumstances.

Level of evidence: 2 TECHNICAL EFFICACY STAGE: 5 J. MAGN. RESON. IMAGING 2020;52:1722-1731.

Keywords: DENSE; feature tracking; myocardial infarction; strain.