The development of Cardiovascular Magnetic Resonance (CMR) has dramatically advanced and offers important advantages compared with other well-established imaging modalities. A series of articles on key topics in CMR gives a greater insight into the rapidly expanding role of CMR in clinical cardiology. The articles can be read in the November/December issue of Progress in Cardiovascular Diseases, published by Elsevier.
Guest editors Theodoros D. Karamitsos, MD, PhD, and Stefan Neubauer, MD, of the University of Oxford Centre for Clinical Magnetic Resonance Research and the Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK, explained:
“Until a decade ago, CMR was considered mostly a research tool, and scans for clinical purpose were rare. With technical advances in hardware and software, CMR is now considered a powerful tool to assess ventricular function, cardiac morphology, perfusion, viability, and metabolism, as well as the vasculature. All of this imaging is possible without the need for ionizing radiation, and with high resolution in three dimensions. CMR is now a highly attractive first-line test for routine clinical indications such as the evaluation of ischemic heart disease and nonischemic cardiomyopathies.
It is anticipated that CMR may still have its best years to come. In the near future, the technique will become even more patient and user friendly, with simplified acquisition approaches, faster real-time scanning protocols, novel contrast agents that target specific molecules for diagnosis and treatment, and advanced tissue characterization that will further improve in vivo assessment of myocardial pathology.”
Cardiovascular Magnetic Resonance: Physics and Terminology
by Christopher T. Rodgers, Matthew D. Robson
The widespread availability of magnetic resonance imagine (MRI) equipment in hospitals shows the extraordinary value of magnetic resonance in medicine. The report provides an introduction to MRI as well as its application in cardiology. The article includes a summary of the important physics underlying CMR, a glossary of important terminology, as well as a references as starting points for further investigations.
Cardiovascular Magnetic Resonance: A Powerful Diagnostic and Prognostic Tool in Modern Cardiology
by Theodoros D. Karamitsos, Stefan Neubauer
CMR is a fairly new imaging method which over the last 30 to 40 years has developed progressively. CMR has been facilitated by its ability to acquire images faster, improve stress perfusion, introduce steady-state free-precision sequences for cine imaging and the development of the late gadolinium enhancement technique to assess myocardial scarring and fibrosis.
Assessment of Myocardial Ischemia with Cardiovascular Magnetic Resonance
by Bobak Heydari, Michael Jerosch-Herold, Raymond Y. Kwong
One of the most prevalent and challenging clinical scenarios physicians face is the evaluation of patients who display symptoms suspicious for myocardial ischemia. CMR can provide physicians were a comprehensive diagnostic and prognostic evaluation of myocardial ischemia for individuals presenting with chest paint, stable angina, or for myocardial viability. Stress CMR is an extremely accurate and safe diagnostic modality that has widespread patient applicability. Stress CMR has been proven to have an advantage for certain patient subgroups, including individuals with baseline left ventricular dysfunction, resting wall motion abnormalities and poor echocardiographic windows. This report includes methods of ischemia evaluation with CMR and compares CMR with other commonly used non-invasive modalities.
Late Gadolinium Enhancement CMR Predicts Adverse Cardiovascular Outcomes and Mortality in Patients With Coronary Artery Disease: Systematic Review and Meta-Analysis
by Filip Zemrak, Steffen E. Petersen
CMR plays a role in the diagnosis and monitoring of coronary artery disease (CAD). Several investigations have demonstrated the CMR can predict adverse outcomes. In this report, the researchers reviewed the contemporary available literature in order to establish CMR’s role with late gadolinium enhancement (LGE) in predicting mortality and major adverse cardiac events (MACEs) in individuals suffering with CAD. They discovered that the hazards of death are increased by over four times when LGE is present and by almost four times when MACE is present. The size of LGE (per gram or percent) increases the hazards of death by 4% and the size of MACE by 5%. The size and presence of LGE predict mortality and MACE in CAD.
Evaluation of Myocardial Viability With Cardiac Magnetic Resonance Imaging
by Suchi Grovera, Govindarajan Srinivasana, Joseph B. Selvanayagam
The management of individuals with ischemic cardiomyopathy and history of myocardial infarction severely relies on the evaluation of left ventricular (LV) function and viability. All of the imaging modalities currently used for viability evaluation have significant limitations related to image quality, poor spatial resolution, and attenuation artifact. In the report the researchers discuss how CMR overcomes these limitations and established itself as a reliable alternative to echocardiography and nuclear methods.
The Role of Cardiovascular Magnetic Resonance in Patients With Acute Coronary Syndromes
by Erica Dall′Armellina, Robin P. Choudhury
CMR is a recognized method for characterization of myocardial tissue in stable ischemic heart disease. Furthermore, CMR can provide a complete characterization of myocardial tissue and can also identify scarred from viable myocardium. This indicates that CMR could play a further role in diagnosing and stratifying individuals with chest pain/acute coronary syndromes (ACSs) at hospitalization or in the early hours prior to revascularization. The investigators of the report assess CMR’s potential role in the acute setting, underlining its limitations and advantages.
Coronary Imaging With Cardiovascular Magnetic Resonance: Current State of the Art
by Amedeo Chiribiri, Masaki Ishida, Eike Nagel, Rene M. Botnar
CMR allows physicians to get a noninvasive, radiation-free visualization of both the veins and coronary arteries, with the benefit of an integrated evaluation of viability, perfusion, anatomy and cardiac function. Furthermore, CMR provides the possibility of coronary vessel wall imaging, therefore evaluating the pathology and anatomy of the normal and dead coronary vessels in a non-invasive manner. CMR angiography is complex due to cardiac and respiratory motion as well as the small size and tortuous path of the coronary vessels. In the report the researchers provide an update on the current technical improvements in CMR angiography, including how to optimize acquisition protocols, as well as an overview of its present clinical applications.
The Current and Emerging Role of Cardiovascular Magnetic Resonance in the Diagnosis of Nonischemic Cardiomyopathies
by Theodoros D. Karamitsos, Jane M. Francis, Stefan Neubauer
CMR allows physicians to get an accurate and reproducible evaluation of cardiovascular anatomy and ventricular function, as well as a detailed myocardial tissue characterization. These unique capabilities make CMR especially attractive for the first evaluation and longitudinal follow-up of individuals with cardiomyopathies. This report presents the primary CMR features of common nonischemic ccardiomyopathies, with particular attention on the specific advantages of this imaging modality.
Cardiovascular Magnetic Resonance Imaging in Myocarditis
by Helene Childs, Matthias G. Friedrich
Just 10% of individuals with myocarditis show clinical symptoms. The majority of patients with myocarditis are often left without a conclusive diagnosis, potentially subject to further myocardial injury. Researchers in this report review how CMR is being used for noninvasive evaluation of individuals who are suspected to have myocarditis, facilitating evaluation of all forms of myocarditis and differentiation from other cardiomyopathies. A recent international consensus on three diagnostic criteria for CMR in the clinical setting is discussed. However, definite diagnosis of myocarditis remains a complex task, the outcome of this disease requires further research with the objective of providing robust noninvasive tests.
The Role of Cardiovascular Magnetic Resonance in the Evaluation of Valve Disease
by Theodoros D. Karamitsos, Saul G. Myerson
In this article investigators look at the best use of CMR in the evaluation of individuals with valve disease and its advantages in key areas. Even though CMR is mainly used in addition to echocardiography, its ability to image all parts of the heart (including complex areas such as the pulmonary valve and RV) makes it an appealing “stand-alone” alternative. CMR provides the best evaluation in quantifying the severity of the valve lesion, determining etiology, and examining the consequences for the relevant ventricle. Further information on the presence of myocardial scar (infarction) or patchy fibrosis and great vessel anatomy can also be clinically helpful.
Assessment of Iron Overload with T2* Magnetic Resonance Imaging
by Lisa J. Anderson
Author Lisa J. Anderson, explains how T2* CMR came to be the preferred method for the evaluation of tissue iron deposition. CMR’s ability to measure ventricular function plus T2* in the heart and liver during the same scan has transformed the understanding of iron storage disease and the management of the iron-loaded patient. The early discoveries using T2* CMR challenged conventional teachings, and both the method and the discoveries were originally viewed with skepticism. However, after 10 years of work in validating, calibrating, and expanding access to this technique, CMR it is now accepted as the preferred method for tissue iron evaluation.
The Role of Cardiovascular Magnetic Resonance in Adults with Congenital Heart Disease
by Philip J. Kilner
Author Philip J. Kilner discusses the role of CMR in the management of adults who suffer with congenital heart disease (ACHD), a patient group that is expanding as advances in cardiac surgery and pediatric cardiology have allowed most of the patients to survive into adulthood. Transthoracic echocardiography continues to be the first-line imaging modality in ACHD. Although, the ability of CMR to provide functional and anatomical information make it helpful in the evaluation and follow-up of adults following procedures, such as aortic coarctation, repairs of tetralogy of Fallot and transposition of the great arteries, and those with Fontan operations or with operated or unoperated complex malformations. CMR in ACHD requires specific training and experience; Kilner advocates that for more difficult cases, CMR should be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients in a tertiary referral center.
Assessment of Pericardial Diseases and Cardiac Masses with Cardiovascular Magnetic Resonance
by Dana Dawson, Raad Mohiaddin
This report focuses on the state-of the- art application of CMR in evaluating pericardial diseases and cardiac tumors, and characterizing these conditions from other noncardiac and cardiac diseases. Several imaging modalities are available for this task and each have advantages and limitations. CMR is very well suited to visualize fine structures, such as the pericardium or to provide detailed anatomical information and tissue characterization of cardiac masses. However, the researchers highlight the technical issues that can compromise accurate image collection; these need to be understood and considered when images are acquired.
Clinical Cardiac Magnetic Resonance Spectroscopy
by Cameron J. Holloway, Joseph Suttie, Sairia Dass, Stefan Neubauer
Cardiac magnetic resonance spectroscopy (MRS) is a strong noninvasive method used for the investigation of cardiac metabolism; especially for, myocardial energetics and lipidosis. Even though it is currently used only in research, with novel technical developments cardiac MRS has the potential to significantly enhance our understanding of cardiac diseases and provide clinical tools for evaluation as well as therapeutic monitoring. This report offers an overview of human cardiac MRS techniques and their application in cardiac disease. Present technical limitations and future directions are also investigated.
Progress in Cardiovascular Diseases Editor-in-Chief, Henry Greenberg, MD, added that:
“This issue, with its own primer on CMR physics and terminology, is a wonderful compendium for the cardiology trainee, pulling together in one place the essential evidence for the role of CMR.”
Written by Grace Rattue