Extent of Myocardium at Risk for Left Anterior Descending Artery, Right Coronary Artery, and Left Circumflex Artery Occlusion Depicted by Contrast-Enhanced Steady State Free Precession and T2-Weighted Short Tau Inversion Recovery Magnetic Resonance Imaging

Abstract

A fter occlusion of a coronary artery, an area corresponding to the perfusion territory of that artery becomes ischemic and will become infarcted unless timely reperfusion occurs. [1][2][3][4][5][6] This area is known as the myocardium at risk (MaR), and it can be used to calculate myocardial salvage index, 7 which is currently used as an end point in at least 19 ongoing clinical trials (Appendix I in the Data Supplement).Background-Contrast-enhanced steady state free precession (CE-SSFP) and T2-weighted short tau inversion recovery (T2-STIR) have been clinically validated to estimate myocardium at risk (MaR) by cardiovascular magnetic resonance while using myocardial perfusion single-photon emission computed tomography as reference standard. Myocardial perfusion single-photon emission computed tomography has been used to describe the coronary perfusion territories during myocardial ischemia. Compared with myocardial perfusion single-photon emission computed tomography, cardiovascular magnetic resonance offers superior image quality and practical advantages. Therefore, the aim was to describe the main coronary perfusion territories using CE-SSFP and T2-STIR cardiovascular magnetic resonance data in patients after acute ST-segment-elevation myocardial infarction. Methods and Results-CE-SSFP and T2-STIR data from 2 recent multicenter trials, CHILL-MI and MITOCARE (n=215),were used to assess MaR. Angiography was used to determine culprit vessel. Of 215 patients, 39% had left anterior descending artery occlusion, 49% had right coronary artery occlusion, and 12% had left circumflex artery occlusion. Mean extent of MaR using CE-SSFP was 44±10% for left anterior descending artery, 31±7% for right coronary artery, and 30±9% for left circumflex artery. Using T2-STIR, MaR was 44±9% for left anterior descending artery, 30±8% for right coronary artery, and 30±12% for left circumflex artery. MaR was visualized in polar plots, and expected overlap was found between right coronary artery and left circumflex artery. Detailed regional data are presented for use in software algorithms as a priori information on the extent of MaR. Conclusions-For the first time, cardiovascular magnetic resonance has been used to show the main coronary perfusion territories using CE-SSFP and T2-STIR. The good agreement between CE-SSFP and T2-STIR from this study and myocardial perfusion single-photon emission computed tomography from previous studies indicates that these 3 methods depict Nordlund et al Extent of Myocardium at RiskEarlier attempts to measure the coronary perfusion territories have relied on animal studies or anatomic studies, such as dissections and casts of the vasculature in autopsy studies. 8,9 More recently, the advent of perfusion imaging, such as by myocardial perfusion single-photon emission computed tomography (MPS), [10][11][12][13][14][15] and tissue characterization by cardiovascular magnetic resonance (CMR) 7,[16][17][18][19] has allowed for visualization of MaR directly. However, only 2 MPS studies with a limited numbe...

The significance of ST‐elevation in aVL in anterolateral myocardial infarction: An assessment by cardiac magnetic resonance imaging

“…These changes include increased myocardial extracellular volume fraction (Jablonowski et al, ) and alterations in T1 and T2 properties which can be utilized for quantification of MaR using CE‐SSFP by MR (Nordlund et al, ; Sorensson et al, ). MaR by CE‐SSFP has been shown to be stable over the first week after the acute event (Nordlund, Klug, et al, ) and this technique enables detailed depiction of MaR for all the major coronary arteries (Nordlund, Heiberg, et al, ). Infarct size can be assessed by LGE MRI (Kim et al, ) and compared to the initial MaR for calculation of myocardial salvage.…”

Advances in Magnetic Resonance Imaging of the Myocardial Area at Risk and Salvage

“…In the study by Nordlund et al, 17 out of 215 CMR scans acquired using technology from different vendors, only 11 CE-SSFP sets were not of diagnostic quality. The scans from 2 other patients were of diagnostic quality, but the area at risk was not apparent.…”

“…The temporal resolution of CE-SSFP was 20 to 30 frames per second. Nordlund et al 17 also set out to compare their results with previous publications on identifying the culprit artery using single photon emission computed tomography. 18,19 The CMR image analyses were performed in a core laboratory using software designed by the same group in the University of Lund, Sweden.…”

“…It is particularly attractive because the data can be acquired from the standard cine scans that are acquired for left ventricular mass and function, without the need for additional breath-hold edema imaging acquisitions. Therefore, the overall duration of the CMR scan would be shorter using CE-SSFP 17 as compared with when additional scans are acquired for edema imaging. Further validation of the accuracy and performance of CE-SSFP 17 against T2 parametric mapping 13 and T1 mapping techniques 12 is warranted.…”

Oxygen therapy in patients with ST elevation myocardial infarction based on the culprit vessel: results from the randomized controlled SOCCER trial

“…None of the above RCTs have however evaluated the effects of supplemental O 2 therapy in patients with STEMI based on the culprit vessel. It has been shown that Left Anterior Descending (LAD) infarction results in both a larger myocardium at risk and a larger infarct size [17] in comparison to non-LAD infarctions. As supplemental O 2 therapy has been suggested to increase oxygen delivery [18][19][20][21][22], it could thereby theoretically have a role in LAD infarcts.…”