Magnetic Resonance Spectroscopy in Myocardial Disease

Hudsmith, Lucy; Neubauer, Stefan

doi:10.1016/j.jcmg.2008.08.005

Cited by 88 publications

(60 citation statements)

References 64 publications

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“…31 Phophorus magnetic resonance spectroscopy studies performed in patients with advanced LV failure have repeatedly demonstrated decreased myocardial levels of creatine and ATP and correlations between these levels and survival. 99 …”

Section: Molecular and Perfusion Imaging Magnetic Resonance Spectroscopymentioning

confidence: 99%

“…128 During the process of apoptosis, the phospholipid phosphatidylserine is expressed on the outer cell membrane and serves as a signal for cell removal by macrophages. 129 Annexin is a protein that binds to phosphatidylserine, and single-photon emission computed tomography imaging showed increased 99 Tc-labeled annexin V uptake in the failing LV 130 and in rejected cardiac transplants. 131 Similar results were obtained in PH animal models, but these data have not yet been confirmed in patients with PAH.…”

Section: Rv Apoptosismentioning

confidence: 99%

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Noninvasive Imaging in the Assessment of the Cardiopulmonary Vascular Unit

et al. 2015

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899N oninvasive imaging plays a key role in both the diagnosis and management of patients with pulmonary hypertension (PH). In recent years, there have been 2 major changes in perspective of imaging in PH. The first was the realization that imaging should focus on the evaluation of not only the pulmonary pressures but also the cardiopulmonary unit ( Figure 1). 1,2The second was the emergence of multimodality imaging with a complementary role for echocardiography, magnetic resonance (MRI), computed tomography, and positron emission tomography (PET).2-7 These techniques not only help in the diagnosis of PH but also help identify factors that determine risk and prognosis and gauge therapeutic effects on right ventricular (RV) function in patients with pulmonary arterial hypertension (PAH). Although echocardiography is the mainstay in the assessment of hemodynamic and ventricular function in PH, MRI has emerged as the gold standard for quantifying volumes, function, and flow in the right side of the heart. 2-7 PET is also offering novel insights into perfusion and blood flow, metabolism, neurohormonal activation, and other molecular processes in the right side of the heart but is used mainly for research at this time. Catheterization of the right side of the heart remains the gold standard for defining PH and assessing hemodynamics both at rest and with exercise. Invasive assessment of cardiac output (CO) may, however, have limited accuracy when assumed instead of measured oxygen consumption is used to derive CO (eg, using the Fick method) or when thermodilution is used in the setting of a low-CO state. [8][9][10] This review covers RV imaging studies performed in the field of PH and discusses recent advances in echocardiography and cardiac MRI and PET imaging for detailed assessment of RV function. The review starts with a discussion of important physiological considerations and unmet needs in imaging research of the right side of the heart in PH. Computed tomography angiography, which plays an important role in evaluating chronic thromboembolic PH, is not discussed extensively in this review. Physiological ConsiderationsAlthough PH is a syndrome affecting the pulmonary vasculature, survival of patients with PH is closely related to RV function. 1,[11][12][13][14] The RV initially adapts to the increased afterload by increasing its wall thickness and contractility. These mechanisms are, however, often insufficient, and RV dysfunction eventually occurs. After the recent Fifth World Symposium on Pulmonary Hypertension, a definition of failure of the right side of the heart secondary to PH was adopted: "Right heart failure in the setting of PH can be defined as a complex clinical syndrome due to a suboptimal delivery of blood or elevated systemic venous pressure at rest or exercise as a consequence of elevated RV afterload."2 The proposed definition takes into account both the systolic and diastolic characteristics of function of the right side of the heart, as well as physiological demands such as exercise.In underst...

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Section: Molecular and Perfusion Imaging Magnetic Resonance Spectroscopymentioning

confidence: 99%

Section: Rv Apoptosismentioning

confidence: 99%

Noninvasive Imaging in the Assessment of the Cardiopulmonary Vascular Unit

et al. 2015

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“…5 Although this technique is currently limited to a substantial extent with regard to determination of energetic status during stress and also imposes substantial limits of spatial resolution within the myocardium, it represents a means to obtain additional insights into the relationships between hemodynamic, autocoidal, and genetic stimuli and the development of left ventricular hypertrophy, myocardial metabolic efficiency, and cardiac function. In this regard, a number of recent publications have documented that left ventricular hypertrophy in general is associated with decreased PCr:ATP ratios, 6 whereas systolic heart failure, irrespective of the presence or absence of underlying large-vessel coronary artery disease, is also associated with impaired energetics.…”

Section: Hcm and Impaired Myocardial Energeticsmentioning

confidence: 99%

Perhexiline and Hypertrophic Cardiomyopathy

Horowitz

Chirkov

2010

Circulation

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“…7 Although cardiac proton MRS studies offer tremendous potential for clinical and research applications, the technique remains challenging to perform and interpret. 8 Furthermore, as opposed to MRI-based techniques such as late gadolinium enhancement, no clinical question has been identified that cardiac MRS can uniquely answer to affect patient treatment, limiting its widespread adaptation. This is in contrast to the research applications of proton MRS to assess myocardial lipid or phosphorus MRS to quantify cardiac high-energy phosphates.…”

Section: Article See P 710mentioning

confidence: 99%

Paying at the Pump

Ruberg

2010

Circ: Cardiovascular Imaging

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C ardiac steatosis, or the abnormal accumulation of myocardial lipid, has recently emerged as an identifiable feature of insulin-resistant states including obesity and type 2 diabetes mellitus. 1 Although the presence of increased myocardial lipid has been associated with both systolic and diastolic dysfunction in human and animal studies, it remains unclear whether accumulated lipid species are intrinsically pathological (the "lipotoxicity" hypothesis) or simply a marker of a fundamental derangement in cellular metabolism. 2 It has been hypothesized that in insulin-resistant states, cellular fatty acid uptake exceeds mitochondrial oxidative capacity, leading to the generation of cytotoxic lipid metabolites that affect cardiac function through a variety of potential mechanisms. 2 Indeed, many of the mouse models that recapitulate the diabetic phenotype and elicit myocardial steatosis also alter cellular systems that regulate lipid metabolism and energy substrate utilization. [3][4][5] Article see p 710It is relatively simple to measure myocardial lipid in animal models because cardiac tissue is readily available ex vivo for histological processing. In vivo measurements from a beating heart and breathing animal, although much more challenging, are possible with the application of imageguided proton magnetic resonance spectroscopy (MRS). 6 Proton MRS is similar to MRI in that protons, principally contained in water and fat in biological tissue, generate a measureable nuclear magnetic resonance (NMR) signal when placed in a strong external magnetic field and exposed to tuned radiofrequency energy. In MRI, the NMR signals from all protons irrespective of their chemical environment are summed to generate an intensity that is localized in space by the application of multiple magnetic field gradients. In MRS, the various populations of protons can be separated into a signal intensity spectrum by differences in their intrinsic resonance signatures. In this way, chemical species' concentrations can be determined noninvasively from a volume of tissue with a high degree of accuracy and reproducibility. Specifically, intracellular lipids can be quantified by determining the total spectral peak areas corresponding to the methylene (CH 2 , seen at approximately 1.4 parts per million) and methyl (CH 3 , seen at approximately 0.8 to 1.0 parts per million) side chains expressed as a fraction of the total water signal (at 4.7 parts per million). 7 Although cardiac proton MRS studies offer tremendous potential for clinical and research applications, the technique remains challenging to perform and interpret. 8 Furthermore, as opposed to MRI-based techniques such as late gadolinium enhancement, no clinical question has been identified that cardiac MRS can uniquely answer to affect patient treatment, limiting its widespread adaptation. This is in contrast to the research applications of proton MRS to assess myocardial lipid or phosphorus MRS to quantify cardiac high-energy phosphates. 9,10 A few centers have developed expertise in ...

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Magnetic Resonance Spectroscopy in Myocardial Disease

Cited by 88 publications

References 64 publications

Noninvasive Imaging in the Assessment of the Cardiopulmonary Vascular Unit

Noninvasive Imaging in the Assessment of the Cardiopulmonary Vascular Unit

Perhexiline and Hypertrophic Cardiomyopathy

Paying at the Pump

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