Analysis of myocardial oedema by magnetic resonance imaging early after coronary artery occlusion with or without reperfusion

Garcı́a-Dorado, David; Oliveras, Juan; Gili, Jaume; Sanz, E; Pérez‐Villa, Félix; Barrabés, José A.; Carreras, Maria Josep; Solares, Julia; Soler‐Soler, Jordi

doi:10.1093/cvr/27.8.1462

Cited by 218 publications

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“…Advances in MR such as novel contrast agents [27], T2 weighted sequences for the detection of oedematous tissue [28] or quantitative assessment of myocardial perfusion were initially validated in pigs [29]. Schmitt et al demonstrated correlation between experimentally reduced coronary perfusion measured with quantitative CMR and fluorescently labelled microspheres [30].…”

Section: Discussionmentioning

confidence: 99%

An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

Schuster

Grünwald

Chiribiri

et al. 2010

Journal of Cardiovascular Magnetic Resonance

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BackgroundNovel cardiovascular magnetic resonance (CMR) techniques and imaging biomarkers are often validated in small animal models or empirically in patients. Direct translation of small animal CMR protocols to humans is rarely possible, while validation in humans is often difficult, slow and occasionally not possible due to ethical considerations. The aim of this study is to overcome these limitations by introducing an MR-compatible, free beating, blood-perfused, isolated pig heart model for the development of novel CMR methodology.Methods6 hearts were perfused outside of the MR environment to establish preparation stability. Coronary perfusion pressure (CPP), coronary blood flow (CBF), left ventricular pressure (LVP), arterial blood gas and electrolyte composition were monitored over 4 hours. Further hearts were perfused within 3T (n = 3) and 1.5T (n = 3) clinical MR scanners, and characterised using functional (CINE), perfusion and late gadolinium enhancement (LGE) imaging. Perfusion imaging was performed globally and selectively for the right (RCA) and left coronary artery (LCA). In one heart the RCA perfusion territory was determined and compared to infarct size after coronary occlusion.ResultsAll physiological parameters measured remained stable and within normal ranges. The model proved amenable to CMR at both field strengths using typical clinical acquisitions. There was good agreement between the RCA perfusion territory measured by selective first pass perfusion and LGE after coronary occlusion (37% versus 36% of the LV respectively).ConclusionsThis flexible model allows imaging of cardiac function in a controllable, beating, human-sized heart using clinical MR systems. It should aid further development, validation and clinical translation of novel CMR methodologies, and imaging sequences.

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Section: Discussionmentioning

confidence: 99%

An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

Schuster

Grünwald

Chiribiri

et al. 2010

Journal of Cardiovascular Magnetic Resonance

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“…16 Using T2-weighted cardiac magnetic resonance (CMR), it is possible to visualize edema in the myocardium retrospectively, even several days after coronary occlusion. 17,18 Experimental studies have demonstrated that the extent of edema is comparable to histopathological and fluorescein measurements of the area at risk. 19 Furthermore, the quantification of irreversible myocardial injury using delayed contrast-enhanced CMR has been extensively validated in acute and chronic settings.…”

Section: How To Measure the Extent Of Myocardium At Riskmentioning

confidence: 94%

Myocardium at risk: Reasons and methods for measuring the extent

Gimelli

Rovai

2013

Journal of Nuclear Cardiology

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See related article, pp. 99-110 MYOCARDIUM AT RISKIf a coronary artery is acutely occluded, the downstream myocardium becomes severely under-perfused and at risk of necrosis. The area of myocardium at jeopardy of infarction is usually referred to as area at risk. It is intuitive that the extent of myocardium at risk downstream from an occluded coronary artery does not have the dimension of an area, but rather that of a volume or a mass. Indeed, the extent of myocardium at risk is usually expressed in grams or in percentage of ventricular myocardium. However, because the initial experiments were carried out by injecting dyes or radionuclide-labeled microspheres upstream from the occluded coronary artery, and because the myocardium at risk was defined postmortem as the non-stained or non-labeled area in cross-sectional slices of the heart, the term area at risk has become common and hence entered the medical dictionary. 1,2 If a flow tracer is injected into a coronary artery proximal to its occlusion, and a second flow tracer is injected after the occlusion upstream the occluded artery, it becomes evident that the extent of myocardium perfused by a given open artery is larger than the myocardium at risk when the same vessel is occluded ( Figure 1A, B). This difference is on average 20% in the canine heart, and is due to the collateral circulation. 3 It has been traditionally assumed that coronary arteries are functional end-arteries under physiological conditions. However, even in the absence of coronary stenoses or in entirely normal hearts, brief periods of coronary occlusion produced by balloon inflation are not followed by electrocardiographic signs of myocardial ischemia in 20%-25% of patients. This is attributed to collateral circulation. 4 This phenomenon is more prominent in the case of preexisting collaterals, as observed in patients with chronic coronary artery disease. Thus, the extent of the area at risk after coronary occlusion is influenced both by an anatomical factor (the size and hierarchy of the occluded vessel) and by a series of functional factors (largely related to the collateral circulation). For this reason, an acute coronary occlusion causes a smaller infarction and a less severe hemodynamic impairment in an older patient with extensive coronary atherosclerosis and well-developed collaterals than in a younger patient without preexisting collaterals. Another functional factor is how rapid is the occlusion. If the occlusion is very slow (as it can be obtained in experimental animals and as it occurs in patients with coronary lesions slowly evolving toward total occlusion), collaterals have the time to develop and to minimize the extent of myocardium at risk. This goes in parallel with the common observation of patients with even complete occlusion of a proximal coronary artery and absence of myocardial infarction. Finally, if the perfusion territory is small, as when a secondary branch is occluded, collateral vessels can totally obscure the area of myocardium at risk. WHY MEASURE THE EXTENT ...

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“…Therefore, an interesting application of T2W imaging has been in the demarcation of the area at risk associated with acute MI. 15,16 The area at risk during an acute coronary event is the salvageable myocardium (hypoperfused but noninfarcted), the salvation of which can determine the therapeutic efficacy of reperfusion therapy. 17 The clinical significance of detecting the area at risk cannot be overemphasized.…”

Section: T2 Mappingmentioning

confidence: 99%

Cardiac Magnetic Resonance Imaging for the Investigation of Cardiovascular Disorders. Part 2: Emerging Applications

Goenka¹,

Wang²,

Flamm³

2014

Texas Heart Institute Journal

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Cardiac magnetic resonance imaging has emerged as a robust noninvasive technique for the investigation of cardiovascular disorders. The coming-of-age of cardiac magnetic resonance-and especially its widening span of applications-has generated both excitement and uncertainty in regard to its potential clinical use and its role vis-à-vis conventional imagC ardiac magnetic resonance imaging (CMR) is unique in its ability to provide comprehensive evaluation of cardiovascular disorders in a single session. Part 1 of this review highlighted the mainstream applications of CMR that are now routinely used for diagnosis, risk stratification, and case management.1 In this section, we provide an overview of the principles and potential applications of emerging CMR techniques that seek to characterize the myocardial substrate in both health and disease. These techniques offer the ability to noninvasively delineate pathophysiologic processes in vivo and, therefore, to expand our understanding of cardiovascular disorders. We also present a synopsis of innovative applications of validated CMR techniques that have the potential to expand the usefulness of CMR as a clinically relevant, cost-effective tool for reliable investigation and accurate case management in a wide variety of clinical situations. T1 Mapping and Extracellular Volume QuantificationDetection of regional or replacement myocardial fibrosis on CMR arises from the visual evaluation of well-delineated areas of late gadolinium enhancement (LGE) on delayed-enhancement MR (DE-MR) imaging. As discussed in Part 1 of this review, 1 high contrast-to-noise ratio in DE-MR imaging is achieved by suppressing the signal from the normal, unaffected myocardium. However, in patients with diffuse interstitial fibrosis, defining the unaffected myocardium can be difficult, which limits the usefulness of DE-MR imaging for detecting diffuse myocardial processes and for quantifying the extent of extracellular matrix (ECM) expansion. Therefore, direct quantification of longitudinal relaxation time of tissue (T1) has been proposed as a novel alternative imaging biomarker of myocardial fibrosis.Depending on the composition of the tissue, T1 relaxation times vary across tissue types. Deviation from established ranges can therefore be used to quantify the effects of pathologic processes.2 The generation of parametric maps that encode T1 value in each pixel of an image is called T1 mapping (Fig. 1).Not only does T1 mapping provide quantitative estimation of diffuse myocardial disease processes and extracellular volume (ECV), but it has the advantage (when compared with DE-MR imaging) of circumventing the influences of windowing, of variations in signal enhancement, and of variability of observer input in characterizing the diseased myocardium.3 Recent robust developments in acquisition and postprocessing techniques have given T1 mapping significant traction.

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Analysis of myocardial oedema by magnetic resonance imaging early after coronary artery occlusion with or without reperfusion

Cited by 218 publications

References 0 publications

An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

Myocardium at risk: Reasons and methods for measuring the extent

Cardiac Magnetic Resonance Imaging for the Investigation of Cardiovascular Disorders. Part 2: Emerging Applications

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