The role of cardiovascular magnetic resonance in heart failure

Cardiovascular Magnetic Resonance (CMR) is an accepted gold standard for non-invasive, accurate, and reproducible assessment of cardiac mass and function. The interest in its use for viability, myocardial perfusion and coronary artery imaging is also widespread and growing rapidly as the hardware and expertise becomes available in more centres, and the scans themselves become more cost effective. In patients with heart failure, accurate and reproducible serial assessment of remodelling is of prognostic importance and the lack of exposure to ionizing radiation is helpful. The concept of an integrated approach to heart failure and its complications using CMR is fast becoming a reality, and this will be tested widely in the coming few years, with the new generation of dedicated CMR scanners.     

Assessment of diastolic function by cardiovascular magnetic resonance

Background The assessment of diastolic heart function has been hampered by multiple difficulties. Cardiovascular magnetic resonance (CMR) is a new, noninvasive technique to study cardiac function. Methods The literature on CMR for the analysis of diastolic function and its clinical applications is extensively reviewed. Results Analysis of ventricular filling velocity and volume flow, volumetric assessment of ventricular chamber volume, analysis of 3-dimensional myocardial strains, and assessment of myocardial energy content are numerous validated applications of CMR. With the advent of real-time imaging and automated analysis of myocardial strains, CMR tagging is a promising method to assess regional diastolic function. Today, many CMR techniques are leaving the experimental or developmental stage rapidly and becoming clinically available for the evaluation of diastolic function in heart disease. Conclusions CMR is emerging as a highly accurate and reproducible noninvasive 3-dimensional technique for the assessment of diastolic function. (Am Heart J 2002;144:198-205.)     

Quantification of Right and Left Ventricular Function by Cardiovascular Magnetic Resonance

Cardiac dysfunction is a major cause of cardiovascular morbidity and mortality. Accurate and reproducible assessment of cardiac function is essential for the diagnosis, the assessment of prognosis and evaluation of a patient's response to therapy. Cardiovascular Magnetic Resonance (CMR) provides a measure of global and regional function that is not only accurate and reproducible but is noninvasive, free of ionising radiation, and independent of the geometric assumptions and acoustic windows that limit echocardiography. With the advent of faster scanners, automated analysis, increasing availability and reducing costs, CMR is fast becoming a clinically tenable reference standard for the measurement of cardiac function. Zusammenfassung Die kardiale Dysfunktion ist eine der Hauptursachen kardiovaskulärer Morbidität und Mortalität. Eine genaue und reproduzierbare Bestimmung der Herzfunktion ist essentiell für die Diagnosestellung, Prognoseabschätzung und Beurteilung des Therapieeffekts beim einzelnen Patienten. Die kardiovaskuläre Magnetresonanztomographie (CMR) bietet eine Messmethode für die globale und regionale Herzfunktion, die nicht nur genau und reproduzierbar, sondern auch nichtinvasiv, ohne ionisierende Strahlung und unabhängig von geometrischen Annahmen und einem akustischen Fenster ist, das den Einsatz der Echokardiographie limitiert. Mit der Verfügbarkeit schnellerer MR-Scanner und automatisierter Analysesysteme sowie mit zunehmender Verbreitung und reduzierten Kosten wird CMR bald den Referenzstandard für die Messung der Herzfunktion darstellen.     

Principles, current status and clinical implications of ischaemic heart disease assessment by cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) has matured into a robust, accurate and highly reproducible imaging modality for the assessment of cardiac function and ischaemic heart disease. The unique physical properties of CMR permit depiction of pathology-specific tissue contrast based on differences in tissue composition, such as myocardial oedema, necrosis and fibrosis. This can be imaged at high spatial resolution allowing characterisation of the acuity of an ischaemic event, the presence and extent of myocardial ischaemia, necrosis and viability. Prognostically important information obtained from CMR evaluation of ischaemic heart disease, such as left ventricular ejection fraction, infarct size and transmurality, infarct location and the presence of intraventricular mechanical dyssynchrony may be used to guide coronary revascularisation, device and medical therapies.     

New generation 3-dimensional echocardiography for left ventricular volumetric and functional measurements: comparison with cardiac magnetic resonance.

AIMS: Non-invasive assessment of left ventricular (LV) structure and function is important in the evaluation of cardiac patients. This study was designed to test the accuracy and reproducibility of new generation 3-dimensional echocardiography (3DE) in measuring volumetric and functional LV indices as compared with current "gold standard" of non-invasive cardiac imaging, cardiac magnetic resonance (CMR). METHODS AND RESULTS: Sixty-four subjects with good acoustic windows, including 40 cardiac patients with LV ejection fraction (EF)<45%, 14 patients with EF>45% and 10 normal volunteers underwent 3DE using a commercially available Philips Sonos 7500 scanner equipped with a matrix phase-array x4 xMATRIX transducer, and CMR on a 1.5 T Signa CV/i scanner (GE Medical Systems). Volumetric assessment was performed with analytical 4D-LV-Analysis software (TomTec) for 3DE and MRI-Mass software (Medis) for CMR. We found no significant differences in LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF with excellent correlations between the indices measured using 3DE and CMR (r=0.97, r=0.98, and r=0.94, respectively). Bland-Altman analysis showed bias of 7 ml for EDV, 3 ml for ESV and -1% for EF with 3DE with corresponding limits of agreement (2SD) of 28 ml, 22 ml and 10%, respectively. Intraobserver and interobserver variabilities were for EDV: 3% and 4% (3DE) vs 2% and 2% (CMR), for ESV: 3% and 6% (3DE) vs 2% and 3% (CMR), and for EF: 4% and 4% (3DE) vs 2% and 4% (CMR), respectively. CONCLUSION: New generation 3DE provides accurate and reproducible quantification of LV volumetric and functional data in subjects with good acoustic windows as compared with CMR.     

Assessment of myocardial ischemia and viability using cardiac magnetic resonance

Cardiac magnetic resonance (CMR) is a burgeoning area of noninvasive cardiac imaging. Today, its clinical utility spans from the qualitative and quantitative assessment of cardiac function and morphology to the challenging task of determining the severity and reversibility of coronary heart disease. Advances in magnet and coil design, pulse sequence, and contrast media have contributed greatly, helping CMR become the multipurpose tool of today's cardiac imaging. This article reviews and explores some of the most exciting clinical applications of CMR in the assessment of coronary artery disease.     

Myocardial perfusion imaging by cardiac magnetic resonance.

Cardiovascular magnetic resonance (CMR) has been shown to provide high quality data on cardiac and valvular function, perfusion, viability, blood flow, and potentially, on cardiac metabolism as well. Several of these CMR applications (eg, function and viability assessment) matured during the past years and are now established components of a cardiac workup. Perfusion-CMR is close to this status and is already a major contributor to cardiac examinations in a growing number of expert centers. Large multicenter perfusion-CMR trials comparing the diagnostic performance of CMR with other techniques were recently reported yielding areas under the receiver-operator-characteristics curve as a high as 0.85 for coronary artery disease detection (MR-IMPACT). Anticipating a growing role for perfusion-CMR in cardiology in the near future, this article discusses the principles of perfusion-CMR and its integration into the workup of patient with coronary artery disease (CAD). In addition to a functional study, this integration is mainly composed of a perfusion-CMR part, followed by a viability assessment by late enhancement CMR techniques. The principal characteristics of these CMR techniques are compared with those of single photon emission computed tomography (SPECT) and positron emission tomography (PET). After introduction into principles and techniques of perfusion-CMR, some open questions in perfusion-CMR and challenges for the future are addressed. Finally, newer CMR applications are shortly mentioned utilizing hyperpolarized carbon-13 compounds in experimental models for quantification of myocardial perfusion and for real-time assessment of metabolic pathways in postischemic myocardium.     

The additional value of gadolinium-enhanced MRI to standard assessment for cardiac involvement in patients with pulmonary sarcoidosis

AIM: To determine whether gadolinium-enhanced cardiac MRI (CMR) was of additional diagnostic value to standard assessment in patients with sarcoidosis who underwent evaluation for cardiac involvement. METHODS: We reviewed the findings in patients with pulmonary sarcoidosis who had been assessed with ECG, Doppler echocardiography, 201Tl scintigraphy, and CMR from 2002 to 2004. RESULTS: Of the 55 evaluated patients, standard evaluation diagnosed cardiac involvement in 13 patients while CMR diagnosed myocardial scarring (mean +/- SD, 2.5 +/- 1.9 segments) [all 6 patients] and impaired systolic left ventricular function (1 patient) in an additional 6 patients. The extent of delayed enhancement correlated with disease duration (p < 0.05), ventricular dimensions and function (p < 0.001), severity of mitral regurgitation (p < 0.05), and the presence of ventricular tachycardias (p < 0.001). Patients in whom cardiac involvement was diagnosed only with CMR had less myocardial scarring and functional impairment (p < 0.05) compared to patients with a diagnosis made by standard assessment. CONCLUSION: CMR provides an accurate estimation of the extent of cardiac involvement and may reveal signs of early infiltration that are not detected by standard assessment. The extent of late enhancement with gadolinium relates to the severity of cardiac involvement and may therefore have prognostic implications.     

Prognostic utility of global longitudinal strain in myocardial infarction

Cardiovascular magnetic resonance(CMR) represents the reference standard for cardiac morphology and function assessment. Since introduction in 2009, CMR feature tracking(CMR-FT) has become a frequently used tool in the assessment of myocardial deformation and wall motion on the basis of routinely acquired b-SSFP cine images. Extensive validation has led to excellent intra-and inter-observer as well as inter-study reproducibility. CMR-FT derived myocardial deformation indices such as left ventricular(LV) strain have been shown to be impaired in cardiac diseases such as cardiomyopathies as well as myocardial infarction. Although LV ejection fraction(LVEF) is the routinely and frequently utilized parameter for systolic myocardial function assessment and major adverse clinical event(MACE) prediction, it fails to assess regional differences. Recently, LV strain has emerged as a superior measure for risk assessment and MACE prediction as compared to the established markers e.g., LVEF. This editorial aims to elucidate current discussions in the field of strain assessment in myocardial infarction in the light of recent data from a large prospective multicentre CMR study.     

The Role of Cardiac MR in New-Onset Heart Failure

In patients with heart failure, cardiovascular magnetic resonance imaging (CMR) allows a multifaceted approach to cardiac evaluation by enabling an assessment of morphology, function, perfusion, viability, tissue characterization, and blood flow during a single comprehensive examination. Given its accuracy and reproducibility, many believe CMR is the reference standard for the noninvasive assessment of ventricular volumes, mass, and function, and offers an ideal means for the serial assessment of disease progression or treatment response in individual patients. Delayed-enhancement (DE)-CMR provides a direct assessment of myopathic processes. This permits a fundamentally different approach than that traditionally taken to ascertaining the etiology of cardiomyopathy, which is vital in patients with nonischemic cardiomyopathy and incidental coronary artery disease and patients with mixed, ischemic and nonischemic cardiomyopathy. Precise tissue characterization with DE-CMR also improves the diagnosis of left ventricular thrombus, for which it is the emerging clinical reference standard. There is a growing body of literature on the utility of CMR for patient risk stratification, and its potential role in important management decisions such as for cardiac resynchronization therapy and defibrillator placement.     

Cardiovascular MRI in clinical trials: expanded applications through novel surrogate endpoints

Recent advances in cardiovascular magnetic resonance (CMR) now allow the accurate and reproducible measurement of many aspects of cardiac and vascular structure and function, with prognostic data emerging for several key imaging biomarkers. These biomarkers are increasingly used in the evaluation of new drugs, devices and lifestyle modifications for the prevention and treatment of cardiovascular disease. This review outlines a conceptual framework for the application of imaging biomarkers to clinical trials, highlights several important CMR techniques which are in use in randomised studies, and reviews certain aspects of trial design, conduct and interpretation in relation to the use of CMR.     

Multimodality Evaluation of the Right Ventricle: An Updated Review

The assessment of the volumes, function, and mechanics of the right ventricle (RV) is very challenging because of the anatomical complexity of the RV. Because RV structure, function, and deformation are very important predictors of cardiovascular morbidity and mortality in patients with heart failure, pulmonary hypertension, congenital heart disease, or arrhythmogenic RV cardiomyopathy, it is of great importance to use an appropriate imaging modality that will provide all necessary information. In everyday clinical practice, 2‐dimensional echocardiography (2DE) represents a method of first choice in RV evaluation. However, cardiac magnetic resonance (CMR) remained the gold standard for RV assessment. The development of new imaging tools, such as 3‐dimensional echocardiography (3DE), provided reliable data, comparable with CMR, and opened a completely new era in RV imaging. So far, 3DE has shown good results in determination of RV volumes and systolic function, and there are indications that it will also provide valuable data about 3‐dimensional RV mechanics, similar to CMR. Two‐dimensional echocardiography–derived strain is currently widely used for the assessment of RV deformation, which has been proven to be a more significant predictor of functional capacity and survival than CMR‐derived RV ejection fraction. The purpose of this review is to summarize currently available data about RV structure, function, and mechanics obtained by different imaging modalities, primarily 2DE and 3DE, and their comparison with CMR and cardiac computed tomography.     

Assessment of ventricular structure and function with multidetector CT and MRI

Accurate, noninvasive assessment of ventricular function is fundamental to providing excellent care to patients with cardiovascular diseases. Three-dimensional imaging using cardiac magnetic resonance (CMR) permits the measurement of ventricular structure and function with such precision and accuracy that it now serves as the standard of reference for this purpose. Multidetector CT (MDCT) permits similar three-dimensional reconstruction and measurement of ventricular function. Available data indicate there is good agreement between MDCT and CMR measurements of ventricular function. Patients with cardiomyopathy and distorted ventricles stand to benefit the most from these techniques, particularly with the possibility of combined noninvasive angiography and systolic function assessment with MDCT.     

Assessment of myocardial viability: comparison of echocardiography versus cardiac magnetic resonance imaging in the current era

Detecting viable myocardium, whether hibernating or stunned, is of clinical significance in patients with coronary artery disease and left ventricular dysfunction. Echocardiographic assessments of myocardial thickening and endocardial excursion during dobutamine infusion provide a highly specific marker for myocardial viability, but with relatively less sensitivity. The additional modalities of myocardial contrast echocardiography and tissue Doppler have recently been proposed to provide further, quantitative measures of myocardial viability assessment. Cardiac magnetic resonance (CMR) has become popular for the assessment of myocardial viability as it can assess cardiac function, volumes, myocardial scar, and perfusion with high-spatial resolution. Both 'delayed enhancement' CMR and dobutamine stress CMR have important roles in the assessment of patients with ischaemic cardiomyopathy. This article reviews the recent advances in both echocardiography and CMR for the clinical assessment of myocardial viability. It attempts to provide a pragmatic approach toward the patient-specific assessment of this important clinical problem.     

Assessment of myocardial ischemia and viability using cardiac magnetic resonance

In the past decade, cardiac magnetic resonance (CMR) has evolved dramatically. Its clinical applications are now a major tool in the diagnosis and prognostic assessment of patients with ischemic heart disease. CMR can be used for detection and quantification of ischemia and for viability assessment using different techniques that are now well validated. Scar can be easily detected using contrast enhancement (late gadolinium enhancement). Ischemia detection is usually achieved with stress CMR techniques, whereas prediction for the recovery of function (detection of dysfunctional but viable myocardial segments) can be deduced from scar and stress imaging. Although determination of which approach is better may depend on the population group, the major advantage of CMR is the ability to integrate different information about anatomy, wall motion, myocardial perfusion, and tissue characterization in a single comprehensive examination.     

The role of cardiovascular magnetic resonance imaging in the diagnosis and prognosis of patients with heart failure

Cardiovascular magnetic resonance (CMR) imaging is a tomographic technique, which allows three-dimensional slice orientation without limitations from acoustic windows inherent to echocardiography. Further advantages of CMR are its high temporal and spatial resolution, its excellent soft tissue resolution and its high blood-to-tissue contrast. Cardiovascular magnetic resonance is currently the only imaging technique, which provides a comprehensive study of both structure and function of the heart as well as myocardial perfusion and viability. Moreover, post-processing of CMR images does not require any geometric assumptions as in echocardiography to determine ventricular dimensions. This is particularly important when evaluating ventricles of patients with chronic heart failure with severely altered morphology that may have regional variations in wall thickness and contractility at least in ischemic cardiomyopathy. The highly reproducible results of CMR imaging have turned this technique into a reference standard for the non-invasive assessment of ventricular dimensions, mass and function. In cases with indeterminate results of clinical, electrocardiographic and particularly echocardiographic findings CMR should be used early in the process of diagnosis of patients with heart failure. Not only can altered structure and degree of ventricular and valvular dysfunctions be accurately assessed but also regional perfusion deficits and/or myocardial scars are easily detected. For therapeutic and prognostic reasons a simple differentiation between ischemic and non-ischemic cardiomyopathy should be achieved as the first diagnostic step. In addition, the type and localization of the late gadolinium enhancement (LGE) phenomenon may aid in non-invasively differentiating the etiology of non-ischemic cardiomyopathy. CMR may also improve the assessment and extent of interventricular and intraventricular dyssynchrony in patients to be selected for cardiac resynchronization therapy (CRT). Lastly, the LGE phenomenon may provide independent prognostic information in patients with a CRT system implanted, as well as in patients with ischemic and non-ischemic cardiomyopathy. Thus, CMR imaging should be implemented early in the diagnostic process of patients with heart failure to significantly improve the speed and accuracy of diagnostic procedures, to control the effect of therapeutic measures, and to select patients with a limited prognosis by assessing the degree of ventricular dysfunction and the extent of myocardial scarring.     

Assessment of myocardial fibrosis with cardiovascular magnetic resonance

Diffuse interstitial or replacement myocardial fibrosis is a common feature of a broad variety of cardiomyopathies. Myocardial fibrosis leads to impaired cardiac diastolic and systolic function and is related to adverse cardiovascular events. Cardiovascular magnetic resonance (CMR) may uniquely characterize the extent of replacement fibrosis and may have prognostic value in various cardiomyopathies. Myocardial longitudinal relaxation time mapping is an emerging technique that could improve CMR's diagnostic accuracy, especially for interstitial diffuse myocardial fibrosis. As such, CMR could be integrated in the monitoring and therapeutic management of a large number of patients. This review summarizes the advantages and limitations of CMR for the assessment of myocardial fibrosis.     

Detection of induced myocardial ischemia during stress cardiovascular magnetic resonance

In the past decade, cardiovascular magnetic resonance (CMR) has evolved considerably. Its clinical applications enable the diagnosis and prognostic assessment of patients with ischemic heart disease. CMR is safe, with absence of any ionizing radiation, and offers the greatest information from a single test, allowing the assessment of myocardial morphology, myocardial function and viability. Stress-CMR can be used for detection and quantification of ischemia. This article analyses the technical approach, the limits and reviews the available literature about diagnostic performance of stress CMR testing and its results in the prognostication of cardiac patients. With further improvements in CMR techniques and the establishment of a standardized study protocol, stress-CMR will play a pivotal role in managing patients with ischemic heart disease.     

Cardiac magnetic resonance imaging for stage B heart failure

Cardiac magnetic resonance imaging (CMR) can play a key role in the assessment and follow-up of patients with stage B heart failure. CMR currently serves as the reference standard for quantifying right and left ventricular size and ejection fraction. Technical advances have also enabled CMR to provide noninvasive tissue characterization and detailed assessments of myocardial performance. Thus, in addition to standard metrics of cardiac structure and function, CMR offers a variety of tools for determining cause, severity, and estimating the prognosis associated with an asymptomatic cardiomyopathy.     

Assessment of pericardial diseases and cardiac masses with cardiovascular magnetic resonance

Imaging plays an important diagnostic and prognostic role in the assessment of pericardial diseases and cardiac tumors and in differentiating these conditions from other cardiac and noncardiac diseases. A number of imaging modalities are available for this task; each has advantages and limitation. Cardiovascular magnetic resonance (CMR) is a highly versatile imaging modality that provides detailed anatomical information, tissue characterization, cardiac function assessment, and evaluation of the impact of these conditions on hemodynamics. In this review we focus on the current state-of-the-art application of cardiovascular magnetic resonance in assessing pericardial diseases and cardiac tumors.