Determining Canine Myocardial Area at Risk with Manganese-enhanced MR Imaging

Natanzon, Alex; Hsu, Li‐Yueh; Arai, Andrew E.

doi:10.1148/radiol.2363040413

Cited by 26 publications

(35 citation statements)

References 46 publications

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“…This opens various possibilities for applications such as longitudinal studies of infarction evolution with different ischemic models, risk zone assessment as previously done in other animal models (18,39), and investigation of drug effect on infarction size. Indeed, in rats, injecting Mn 2þ at the beginning of occlusion instead of after reperfusion led to an accumulation of ions in the well perfused myocardium, showing the area at risk as a hypointense signal in MEMRI (18).…”

Section: Further Applicationsmentioning

confidence: 96%

Myocardial infarction quantification with Manganese‐Enhanced MRI (MEMRI) in mice using a 3T clinical scanner

et al. 2010

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Manganese (Mn(2+)) was recognized early as an efficient intracellular MR contrast agent to assess cardiomyocyte viability. It had previously been used for the assessment of myocardial infarction in various animal models from pig to mouse. However, whether Manganese-Enhanced MRI (MEMRI) is also able to assess infarction in the acute phase of a coronary occlusion reperfusion model in mice has not yet been demonstrated. This model is of particular interest as it is closer to the situation encountered in the clinical setting. This study aimed to measure infarction volume taking TTC staining as a gold standard, as well as global and regional function before and after Mn(2+) injection using a clinical 3T scanner. The first step of this study was to perform a dose-response curve in order to optimize the injection protocol. Infarction volume measured with MEMRI was strongly correlated to TTC staining. Ejection fraction (EF) and percent wall thickening measurements allowed evaluation of global and regional function. While EF must be measured before Mn(2+) injection to avoid bias introduced by the reduction of contrast in cine images, percent wall thickening can be measured either before or after Mn(2+) injection and depicts accurately infarct related contraction deficit. This study is the first step for further longitudinal studies of cardiac disease in mice on a clinical 3T scanner, a widely available platform.

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Section: Further Applicationsmentioning

confidence: 96%

Myocardial infarction quantification with Manganese‐Enhanced MRI (MEMRI) in mice using a 3T clinical scanner

et al. 2010

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“…Similar approaches may be feasible with manganese-enhanced cardiac magnetic resonance (CMR). 9 Prolonged abnormalities in metabolism may highlight the area at risk and allow administration of newer SPECT agents after intervention. 10 T2-weighted (T2W) CMR may provide an alternative approach.…”

Section: Editorial P 1821 Clinical Perspective P 1870mentioning

confidence: 99%

Retrospective Determination of the Area at Risk for Reperfused Acute Myocardial Infarction With T2-Weighted Cardiac Magnetic Resonance Imaging

et al. 2006

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Background-The aim of this study was to determine whether edema imaging by T2-weighted cardiac magnetic resonance (CMR) imaging could retrospectively delineate the area at risk in reperfused myocardial infarction. We hypothesized that the size of the area at risk during a transient occlusion would be similar to the T2-weighted hyperintense region observed 2 days later, that the T2-weighted hyperintense myocardium would show partial functional recovery after 2 months, and that the T2 abnormality would resolve over 2 months. Methods and Results-Seventeen dogs underwent a 90-minute coronary artery occlusion, followed by reperfusion. The area at risk, as measured with microspheres (9 animals), was comparable to the size of the hyperintense zone on T2-weighted images 2 days later (43.4Ϯ3.3% versus 43.0Ϯ3.4% of the left ventricle; PϭNS), and the 2 measures correlated (Rϭ0.84). The infarcted zone was significantly smaller (23.1Ϯ3.7; both PϽ0.001). To test whether the hyperintense myocardium would exhibit partial functional recovery over time, 8 animals were imaged on day 2 and 2 months later. Systolic strain was mapped with displacement encoding with stimulated echoes. Edema, as detected by a hyperintense zone on T2-weighted images, resolved, and regional radial systolic strain partially improved from 4.9Ϯ0.7 to 13.1Ϯ1.5 (Pϭ0.001) over 2 months. Conclusions-These findings are consistent with the premise that the T2 abnormality depicts the area at risk, a zone of reversibly and irreversibly injured myocardium associated with reperfused subendocardial infarctions. The persistence of postischemic edema allows T2-weighted CMR to delineate the area at risk 2 days after reperfused myocardial infarction.

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“…As manganese cations enter normal cardiac myocytes through calcium channels and remain there for hours, the use of MRI in the presence of MnCl 2 has recently been proposed for the non-invasive assessment of the myocardial area at risk (3). MnCl 2 is infused during coronary occlusion so that the manganese cations enter only the perfused myocytes and not the area at risk.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of complementary spatial modulation of magnetization tagging in the rat heart after manganese injection

et al. 2007

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It has been shown that manganese-enhanced MRI (MEMRI) can safely depict the myocardial area at risk in models of coronary occlusion-reperfusion for at least 2 h after reperfusion. To achieve this, a solution of MnCl(2) is injected during coronary occlusion. In this model, the regional function quantification deficit of the stunning phase cannot be assessed before contrast injection using MR tagging. The relaxation effects of manganese (which remains in normal cardiac myocytes for several hours) may alter the tags by increasing tag fading and hence the quality of strain measurement. Therefore, we evaluated the feasibility of cardiac MR tagging after manganese injection in normal rats. Six normal Sprague-Dawley rats were imaged in vivo using complementary spatial modulation of magnetization (C-SPAMM) at 1.5 T, before and 15 min after intraperitoneal injection of MnCl(2) solution (~17.5 micromol kg(-1)). The contrast-to-noise ratio of the tag pattern increased significantly (P < 0.001) after injection and remained comparable to the control scan in spite of the higher myocardial relaxation rate caused by the presence of manganese. The measurements of circumferential strain obtained from harmonic phase imaging analysis of the tagged images after MnCl(2) injection did not differ significantly from the measurements before injection in the endocardial, mid-wall, and epicardial regions. In particular, the transmural strain gradient was preserved. Thus, our study suggests that MR tagging could be used in combination with MEMRI to study the acute phase of coronary artery disease.

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Determining Canine Myocardial Area at Risk with Manganese-enhanced MR Imaging

Abstract: Manganese-enhanced MR imaging can depict the area at risk during LAD artery occlusion and at least 2 hours after reperfusion without hemodynamic compromise.

Cited by 26 publications

References 46 publications

Myocardial infarction quantification with Manganese‐Enhanced MRI (MEMRI) in mice using a 3T clinical scanner

Myocardial infarction quantification with Manganese‐Enhanced MRI (MEMRI) in mice using a 3T clinical scanner

Retrospective Determination of the Area at Risk for Reperfused Acute Myocardial Infarction With T2-Weighted Cardiac Magnetic Resonance Imaging

Feasibility of complementary spatial modulation of magnetization tagging in the rat heart after manganese injection

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