Nuclear magnetic resonance imaging of acute myocardial infarction in dogs: Alterations in magnetic relaxation times

Higgins, Charles B.; Herfkens, Robert J.; Lipton, Martin J.; Sievers, Richard E.; Sheldon, P E; Kaufman, Léon; Crooks, Lawrence E.

doi:10.1016/0002-9149(83)90093-0

Cited by 351 publications

(149 citation statements)

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“…Published case reports of cardiac rupture describe hypoenhancement of the aŠected ventricular wall caused by arterial obstruction or late gadolinium enhancement in cardiac MR imaging, 2-4 but detailed MRˆndings of cardiac rupture have not been reported. T 2 -weighted images can reveal areas of high SI caused by edema in patients with AMI, 5,6 and the high SI on T 2 WI and edema at the outer side of the lesion of our patient were compatible with theseˆndings. The diŠerentˆndings in the ruptured myocardium might be caused by the presence of myocardial hemorrhage because the MRˆndings of epicardial hemorrhage were similar.…”

Section: Discussionsupporting

confidence: 84%

Cardiac Rupture in Acute Myocardial Infarction: Post-mortem MR Imaging

et al. 2011

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We assessed acute myocardial infarction (AMI) with cardiac rupture in an autopsy using magnetic resonance (MR) imaging in vitro and histological staining. Cardiac MR imaging in vitro generated high resolution images of myocardial thinning, rupture, and epicardial hemorrhage. High signal intensity (SI) on T 1 weighted images (WI) and low SI on T 2 WI of the rupture site corresponded with acute myocardial necrosis, edema, and hemorrhage. A rupture site rich in erythrocytes after AMI might aŠect SI on T 1 and T 2 WI in cardiac MR imaging.

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Section: Discussionsupporting

confidence: 84%

Cardiac Rupture in Acute Myocardial Infarction: Post-mortem MR Imaging

et al. 2011

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“…T2-weighted images showsignal enhancement in acute MI [12,22,23], correlating with an increase water content and edema [24,25]. T2-weighted CMR is ambiguously sensitive to chronic MI, with no observed increase in signal intensity or T2 relaxation at the site of infarct [6] or changes in T2 that were dependent on the location of infarction [26].…”

Section: Discussionmentioning

confidence: 99%

In vivo chronic myocardial infarction characterization by spin locked cardiovascular magnetic resonance

Witschey

Zsido

Koomalsingh

et al. 2012

Journal of Cardiovascular Magnetic Resonance

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BackgroundLate gadolinium enhanced (LGE) cardiovascular magnetic resonance (CMR) is frequently used to evaluate myocardial viability, estimate total infarct size and transmurality, but is not always straightforward is and contraindicated in patients with renal failure because of the risk of nephrogenic systemic fibrosis. T2- and T1-weighted CMR alone is however relatively insensitive to chronic myocardial infarction (MI) in the absence of a contrast agent. The objective of this manuscript is to explore T1ρ-weighted rotating frame CMR techniques for infarct characterization without contrast agents. We hypothesize that T1ρ CMR accurately measures infarct size in chronic MI on account of a large change in T1ρ relaxation time between scar and myocardium.Methods7Yorkshire swine underwent CMR at 8 weeks post-surgical induction of apical or posterolateral myocardial infarction. Late gadolinium enhanced and T1ρ CMR were performed at high resolution to visualize MI. T1ρ-weighted imaging was performed with a B1 = 500 Hz spin lock pulse on a 3 T clinical MR scanner. Following sacrifice, the heart was excised and infarct size was calculated by optical planimetry. Infarct size was calculated for all three methods (LGE, T1ρ and planimetry) and statistical analysis was performed. T1ρ relaxation time maps were computed from multiple T1ρ-weighted images at varying spin lock duration.ResultsMean infarct contrast-to-noise ratio (CNR) in LGE and T1ρ CMR was 2.8 ± 0.1 and 2.7 ± 0.1. The variation in signal intensity of tissues was found to be, in order of decreasing signal intensity, LV blood, fat and edema, infarct and healthy myocardium. Infarct size measured by T1ρ CMR (21.1% ± 1.4%) was not significantly different from LGE CMR (22.2% ± 1.5%) or planimetry (21.1% ± 2.7%; p < 0.05).T1ρ relaxation times were T1ρinfarct = 91.7 ms in the infarct and T1ρremote = 47.2 ms in the remote myocardium.ConclusionsT1ρ-weighted imaging using long spin locking pulses enables high discrimination between infarct and myocardium. T1ρ CMR may be useful to visualizing MI without the need for exogenous contrast agents for a wide range of clinical cardiac applications such as to distinguish edema and scar tissue and tissue characterization of myocarditis and ventricular fibrosis.

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“…Already in the early eighties of the last century, unenhanced clinical MR imaging showed promising results for the identification of myocardial infarction in the living due to the increase of water (edema) within the infarcted muscle. 21,22 Whereas clinical cardiac MR imaging in recent years improved different contrast agents and implemented application schedules as well as contrast agent and cardiac motion adapted sequences to better assess cardiac pathology 17,[23][24][25][26] , postmortem cardiac MR imaging fully depends on imaging of unenhanced structural alterations at different stages of myocardial infarction. These stages showed a specific signal behavior in pmMRI that allow an age staging of the infarction.…”

Section: Discussionmentioning

confidence: 99%