Synopsis

Keywords: Myocardium, Perfusion

Fully quantitative CMR-MPI was preliminarily applied for evaluating the area at risk in patients with acute ST elevation myocardial infarction. As a result, the fully quantitative CMR-MPI provided quantitative myocardial blood flow of the infarction territories, which was correlated with the extent of Salvageable zone.

abstract

INTRODUCTION: Cardiovascular magnetic resonance (CMR) can play a key role in evaluating the presence of myocardial edema and myocardial infarction in patients with acute myocardial infarction(1,2). Besides, the area at risk (AAR) represents the mismatch between the edematous myocardium and myocardial area of late gadolinium enhancement (LGE) and can be salvaged by timely revascularization(1). CMR myocardial perfusion imaging (CMR-MPI) can be helpful to decrease the need of coronary revascularization(3). Recently, the fully-automated framework for the quantification of myocardial blood flow (MBF) has been developed(4,5). So far, the AAR was routinely defined by qualitative methods. Moreover, no study applied the fully quantitative CMR-MPI for evaluating the AAR in patients with acute myocardial infarction. Therefore, the current study aimed to evaluate the correlation between the extent of salvageable zone in the AAR and the relevant myocardial blood flow obtained by using fully quantitative CMR-MPI. METHODS: This prospective study enrolled patients with ST elevation myocardial infarction (STEMI). And all patients underwent comprehensive CMR protocol including T2 short-tau inversion recovery (T2 STIR), rest fully quantitative CMR-MPI, and LGE sequence. All CMR scans were performed on a 3.0 T MR scanner (Ingenia CX, Philips Healthcare). The MR scanner can provide in-line acquisition and post-processed framework of fully quantitative CMR-MPI, which can generate the myocardial blood flow (MBF) of each segment and coronary territory of the left ventricular myocardium based on the 17-segment model excluding the apical segment(6). The salvageable zone in the AAR was defined by combination the T2-STIR and LGE images. For the correlation analysis, on the segment basis and slice basis (from basal to the apical slices) was analyzed respectively. RESULTS: We finally included 15 patients (65±6.9 years) with STEMI. The interval time between the diagnosis of STEMI and CMR scan both was 7 days. On territory basis, the MBF of the AAR was not significantly correlated with the extent of the salvageable zone (p= 0.319, r=-0.352). Nevertheless, on the slice basis, the MBF of the AAR was significantly correlated with the extent of the salvageable zone (p= 0.023, r=0.415). DISCUSSION: AAR was routinely evaluated by T2 STIR and LGE. Unfortunately, the longtime of acquisition and the need of breath-holding the common disadvantages of both T2 STIR and LGE acquisition. The current study preliminarily applied the fully quantitative CMR-MPI for evaluating the AAR, which can overwhelm the above disadvantages of T2-STIR and LGE. In addition, the fully quantitative CMR-MPI provided the probability of quantitatively assessing AAR. CONCLUSION: Fully quantitative CMR-MPI can provide quantitative MBF flow of the AAR, which was significantly correlated with the extent of the salvageable zone.

Acknowledgements

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