Resonance Imaging In Myocardial Infarction Research Articles

How to Use Cardiac Magnetic Resonance Imaging in Myocardial Infarction With Nonobstructive Coronary Arteries.

The working diagnosis Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA) is being increasingly recognized with the common use of high-sensitivity troponins and coronary angiography, accounting for 5% to 10% of all acute myocardial infarction presentations. Cardiac magnetic resonance (CMR) imaging is pivotal in patients presenting with suspected MINOCA, mainly to delineate those with a nonischemic cause, for example, myocarditis and Takotsubo syndrome, from those with true ischemic myocardial infarction, that is, MINOCA. The optimal timing for CMR imaging in patients with suspected MINOCA has been uncertain and, until recently, not been examined prospectively. Previous retrospective studies have indicated that the diagnostic yield decreases with time from the acute event. The SMINC studies (Stockholm Myocardial Infarction with Normal Coronaries) show that CMR should be performed early in all patients with the working diagnosis of MINOCA, with the possible exception of patients who are clearly identified as having Takotsubo syndrome as determined by echocardiography. In addition to CMR imaging, other investigations of importance in selected patients may be pulmonary artery computed tomography to exclude pulmonary embolism, optical coherence tomography to identify plaque disruption, and acetylcholine provocation to identify coronary artery spasm. Imaging of patients with the working diagnosis MINOCA, which is centered on CMR together with supplemental investigations, results in a clear diagnosis in approximately three-quarters of the patients. This is a good example of personalized medicine, because a correct diagnosis will not only increase the satisfaction of the individual patient but also result in optimizing treatment without harming the patient.

Role of Cardiac Magnetic Resonance Imaging in Myocardial Infarction.

The purpose of the present paper is to analytically review the diagnostic and prognostic role of CMR in ST-segment elevation myocardial infarction (STEMI) survivors. Percutaneous coronary intervention (PCI) is the treatment of choice in patients STEMI. However, risk of future events remains substantial. Assessment of the extent of myocardial infarction (MI), cardiac function and ventricular remodelling has become the focus of recent studies. Electrocardiography, angiography and echocardiography parameters, as well as risk scores, lack sensitivity and reproducibility in predicting future cardiovascular events. A major advantage of cardiac magnetic resonance imaging (CMR) is that it provides myocardial tissue characterization. CMR is able to quantify both reversible and irreversible myocardial injury and correlates with future events. This review will illustrate how microvascular function indices (myocardial salvage index, presence and amount of microvascular obstruction and intramyocardial haemorrhage) detectable by CMR add prognostic information and could impact on future strategies to improve outcomes in revascularized patients.

Cardiovascular Magnetic Resonance Imaging of Myocardial Infarction, Viability, and Cardiomyopathies

Cardiovascular magnetic resonance provides the opportunity for a truly comprehensive evaluation of patients with a history of myocardial infarction, with regard to characterizing the extent of disease, effect on left ventricular function, and degree of viable myocardium. The use of contrast-enhanced cardiac magnetic resonance (CMR) imaging for first-pass perfusion and late gadolinium enhancement is a powerful technique for delineating areas of myocardial ischemia and infarction. Using a combination of T2-weighted and contrast-enhanced CMR images, information about the acuity of an infarct can be obtained. There is extensive published data using contrast-enhanced CMR to predict myocardial functional recovery with revascularization in patients with ischemic cardiomyopathies. In addition, CMR imaging in patients with cardiomyopathies can distinguish between ischemic and nonischemic etiologies, with the ability to further characterize the underlying pathology of nonischemic cardiomyopathies.

Postmortem unenhanced magnetic resonance imaging of myocardial infarction in correlation to histological infarction age characterization

Postmortem magnetic resonance (MRI) imaging is currently evaluated as alternative to traditional autopsy and myocardial infarction plays a key role therein. The aim of this study is to determine the suitability of postmortem MRI in infarction age staging. In eight human forensic corpses presenting with a total of 11 myocardial infarcted areas, short-axis, transversal, and longitudinal long-axis images (T1, T2, stir, flair) were acquired in situ on a 1.5 T system. During subsequent autopsy, the section technique was adapted to short-axis images. Histological investigations were performed along the entire circumference of the left ventricle to correlate the signal alteration in MR to the histological appearance. Two peracute infarctions were not detected in MRI and autopsy. Four acute infarcted areas presented with decreased signal in necrotic centres and increased signal in marginal myocardial regions (T2-weighted). T1-weighted images showed local hyperintensities when intramyocardial haemorrhage occurred. Four cases showed subacute infarctions with hyperintense regions in T2-weighted images and no signal alteration in T1-weighted images. Four chronic myocardial infarctions showed distinctively decreased signals in all applied sequences. Postmortem MRI demonstrates myocardial infarction in situ and allows for an infarction age estimation based on the signal behaviour.

Magnetic resonance imaging of myocardial infarction using a manganese‐based contrast agent (EVP 1001‐1): Preliminary results in a Dog model

To investigate the MRI characteristics of an intracellular manganese-based contrast agent, EVP 1001-1 (Eagle Vision Pharmaceutical Corp.), in a canine model of myocardial infarction. Three dogs were imaged 14-37 days following permanent ligation of the left anterior descending coronary artery (LAD). Measurements of the longitudinal relaxation rate R(1) were made prior to EVP 1001-1 administration (20 micromol/kg i.v.) and for one hour thereafter. Triphenyl tetrazolium chloride (TTC) staining was used to document infarction. In normal myocardium, EVP 1001-1 produced a substantial increase in the longitudinal relaxation rate, which remained fairly constant over the postcontrast imaging period (DeltaR1= 1.47 +/- 0.58 sec(-1) (mean +/- SD) at 35 minutes, P < 0.05). In the infarct, the response to EVP 1001-1 was small or negligible (DeltaR1= 0.27 +/- 0.28 sec(-1)). This resulted in a significant postcontrast difference in relaxation rate between normal and infarcted tissue (R1(normal) - R1(infarct) = 1.08 +/- 0.26 sec(-1), P < 0.05). The infarct remained clearly delineated in all animals throughout the steady-state imaging period, and qualitatively matched TTC results. The persistent enhancement pattern revealed by MRI following EVP 1001-1 administration may be beneficial for identifying and characterizing myocardial infarction.

Magnetic resonance imaging of myocardial infarction: Correlation with enzymatic, angiographic, and radionuclide findings

Spin-echo cardiac magnetic resonance imaging studies were performed in 20 patients with a first 7-to 14-day-old (mean 10) myocardial infarction. The magnetic resonance imaging findings were compared with coronary angiography (14 patients), myocardial enzyme release (18 patients), radionuclide angiography (19 patients), and thallium-201 perfusion scintigraphy (19 patients). Regional T2 relaxation times determined from the signal intensities at echo times 30 msec and 90 msec were significantly prolonged in the infarcted areas. Based on abnormal T2 times for every patient, a regional and a total myocardial damage score was determined. The infarct-related artery was correctly identified in 93% of patients by magnetic resonance imaging, in 79% of patients by thallium-201 scintigraphy, and in 62% of patients by radionuclide angiography. The total damage score correlated well with enzymatic infarct size ( r = 0.75, p < 0.001). The correlation between left ventricular end-systolic volume index determined by magnetic resonance imaging and by radionuclide angiography was r = 0.89 ( p < 0.002). The left ventricular end-systolic volume index correlated significantly with enzymatic infarct size ( r = 0.72, p < 0.001), total damage score ( r = 0.68, p < 0.002), and radionuclide left ventricular ejection fraction ( r = −0.68, p < 0.002). Correlations between the magnetic resonance damage score and the thallium-201 perfusion score were r = 0.60 ( p < 0.01) for the exercise images, and r = 0.72 ( p < 0.001) for the redistribution images. This study shows that spin-echo magnetic resonance imaging is quite comparable with the established noninvasive imaging modalities currently used in patients with acute myocardial infarction.

Magnetic resonance imaging of myocardial infarction in kawasaki disease

We performed magnetic resonance imaging in patients with Kawasaki disease following myocardial infarction to assess the usefulness of the technique in detecting myocardial infarction and coronary artery lesions. In six patients (group A), the interval after myocardial infarction was from 7 days to 7 months, and in five patients (group B), it was from 1 to 4 years. Imaging was performed with a superconducting magnet operating at 0.5 T with spin-echo sequence and ECG-gated multiple slices of 5 mm thickness. Myocardial signals were increased in group A, and the region of high signal intensity corresponded to the site of myocardial infarction. The signal intensity within the myocardium was homogeneous in five patients in group B. Coronary arteries were visualized in 20 of 22 instances. Signals within the coronary artery were observed in all 14 instances with poor contrast runoff from the coronary aneurysm, and 11 of these vessels showed high signal intensity. In all six instances in which large aneurysms with severe stenosis were present, signals in the coronary artery were increased. In contrast, high signal intensity in the coronary artery was not observed in five of six instances with good contrast runoff. Signals in the coronary arterial cavity and high signal intensity in the coronary artery persisted in five of six instances with turbulent coronary flow. The findings of increased coronary arterial signals suggested stagnant blood flow in the coronary aneurysm. In conclusion, magnetic resonance imaging was a useful modality for assessment of myocardial infarction and coronary artery lesions in Kawasaki disease.

Magnetic resonance imaging in myocardial infarction

Magnetic resonance imaging in myocardial infarction

Improved in vivo magnetic resonance imaging of acute myocardial infarction after intravenous paramagnetic contrast agent administration

Gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA), a paramagnetic relaxation agent, has been used in vitro to improve the detection of acute myocardial infarction (MI) by magnetic resonance imaging (MRI). In this study, the ability of Gd-DTPA to improve in vivo magnetic resonance imaging of MI was examined. Ten dogs with MI caused by left anterior descending coronary artery ligation were imaged 1 to 5 days after infarction. Imaging was performed before and for 2 hours after intravenous administration of 0.34 mmol/kg Gd-DTPA. One to 2 days after MI, Gd-DTPA improved visualization of the infarct in 3 of 4 dogs. This effect was more prominent in dogs imaged 4 to 5 days after MI, when 6 of 6 dogs showed substantially improved infarct definition after Gd-DTPA. At both times the intensity ratio, an objective measure of contrast between infarcted and normal tissue that is defined by the ratio of image intensity of infarcted area to that of noninfarcted area, was significantly better after Gd-DTPA administration. The intensity ratio at 24 to 48 hours after infarction was 1.4 ± 0.2 (mean ± standard deviation) before Gd-DTPA, and 1.7 ± 0.6 after Gd-DTPA (p = 0.03). The intensity ratio at 4 to 5 days after infarction was 1.5 ± 0.3 before Gd-DTPA, and 1.8 ± 0.5 after Gd-DTPA (p < 0.001). Thus, Gd-DTPA administration improves in vivo visualization of MI by MRI.

Effect of manganese on transmembrane potential and contractility of atrial muscle.

ARTICLESEffect of manganese on transmembrane potential and contractility of atrial muscleT Yanaga, and WC HollandT Yanaga, and WC HollandPublished Online:01 Nov 1969https://doi.org/10.1152/ajplegacy.1969.217.5.1280MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByApplications for Transition-Metal Chemistry in Contrast-Enhanced Magnetic Resonance Imaging5 May 2020 | Inorganic Chemistry, Vol. 59, No. 10Murine Cardiac Hemodynamics Following Manganese Administration Under Isoflurane Anesthesia5 August 2011 | Annals of Biomedical Engineering, Vol. 39, No. 11Contrast enhancement of manganese-hydroxypropyl-tetraacetic acid, an MR contrast agent with potential for detecting differences in myocardial blood flowJournal of Magnetic Resonance Imaging, Vol. 24, No. 4Magnetic resonance imaging of myocardial infarction using a manganese-based contrast agent (EVP 1001-1): Preliminary results in a Dog modelJournal of Magnetic Resonance Imaging, Vol. 23, No. 2Preliminary Evaluation of EVP 1001-1Investigative Radiology, Vol. 38, No. 10Dose-related effects of manganese on the canine electrocardiogramJournal of Electrocardiology, Vol. 15, No. 2THEOPHYLLINE AND PHENYLEPHRINE EFFECTS ON CARDIAC RELAXATION19 July 2012 | British Journal of Pharmacology, Vol. 59, No. 1Neuromuscular blocking action of cadmium and manganese in isolated frog striated musclesEuropean Journal of Pharmacology, Vol. 40, No. 1Energy-dependent Mn2+ and Ca2+ uptake by the Embryonic chick chorioallantoic membraneBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 426, No. 3The Effect of Calcium, Practolol, Atropine and Phenoxybenzamine on the Rat Atrial Action Potential at Threshold and Supra-threshold Stimulation13 March 2009 | Acta Pharmacologica et Toxicologica, Vol. 37, No. 4Manganese amd electrogenic phenomena in canine Purkinje fibers.Circulation Research, Vol. 36, No. 3Effect on Mn2+ on permeability properties of frog skinPfl�gers Archiv European Journal of Physiology, Vol. 359, No. 1-2Effect of Manganese Ions on the Contraction and Automaticity of the Blood-Perfused Canine Papillary MuscleJapanese Journal of Pharmacology, Vol. 24, No. 5The electrical activity of the bundle of HisPfl�gers Archiv European Journal of Physiology, Vol. 345, No. 1Effect of divalent manganese ions on action potential and contractility of cardiac muscleNaunyn-Schmiedeberg's Archives of Pharmacology, Vol. 275, No. 2ACUTE STRESS AND TRACE ELEMENT METABOLISMComparison of the inotropic response to glucagon, ouabain and noradrenaline19 July 2012 | British Journal of Pharmacology, Vol. 40, No. 3 More from this issue > Volume 217Issue 5November 1969Pages 1280-1285 Copyright & PermissionsCopyright © 1969 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1969.217.5.1280PubMed5346291History Published online 1 November 1969 Published in print 1 November 1969 Metrics