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.)     

Real time three-dimensional echocardiographic assessment of left ventricular function in heart failure patients: underestimation of left ventricular volume increases with the degree of dilatation

Background: Accurate quantification of left ventricular (LV) volumes and ejection fraction (EF) is of critical importance. Cardiac magnetic resonance (CMR) is considered as the reference and three-dimensional echocardiography (3DE) is an accurate method, but only few data are available in heart failure patients. We therefore sought to compare the accuracy of real time three-dimensional echocardiography (RT3DE) and two-dimensional echocardiography (2DE) for quantification of LV volumes and EF, relative to CMR imaging in an unselected population of heart failure patients. Methods and Results: We studied 24 patients (17 men, age 58 ± 15 years) with history of heart failure who underwent echocardiographic assessment of LV function (2DE, RT3DE) and CMR within a period of 24 hours. Mean LV end-diastolic volume (LVEDV) was 208 ± 109 mL (121 ± 64 mL/m(2) ) and mean LVEF was 31 ± 12.8%. 3DE data sets correlate well with CMR, particularly with respect to the EF (r: 0.8, 0.86, and 0.95; P < 0.0001 for LVEDV, LVESV, and EF, respectively) with small biases (-55 mL, -44 mL, 1.1%) and acceptable limits of agreement. RT3DE provides more accurate measurements of LVEF than 2DE (z= 2.1, P = 0.037) and lower variability. However, 3DE-derived LV volumes are significantly underestimated in patients with severe LV dilatation. In patients with LVEDV below 120 mL/m(2) , RT3DE is more accurate for volumes and EF evaluation. Conclusion: Compared with CMR, RT3DE is accurate for evaluation of EF and feasible in all our heart failure patients, at the expense of a significant underestimation of LV volumes, particularly when LVEDV is above 120 mL/m(2) .     

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.     

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.     

心脏核磁共振成像技术在肥厚型心肌病中的应用现状及最新进展

Hypertrophic cardiomyopathy(HCM)is the most common genetic cardiomyopathy and the leading cause of sudden death in young people and a major cause of heart failure symptoms at any age.Due to its genetic etiology,there is substantial heterogeneity in the phenotypic expression and clinical course of patients with HCM.Traditionally,two-dimensional echocardiography has been the easiest and reliable technique for establishing a diagnosis of HCM.However,cardiovascular magnetic resonance(CMR)has emerged as a novel,3-dimensional tomographic imaging technique,which provides high spatial and temporal resolution images of the heart (not limited by thoracic or pulmonary parenchyma),in any plane and without ionizing radiation.As a result,CMR is particularly well suited to provide detailed characterization of the HCM phenotype,including a precise assessment of the location and distribution of LV wall thickening(as well as other myocardial structures such as the right ventricle and papillary muscles).In this regard,CMR has been demonstrated to provide a diagnosis of HCM in cases where the echocardiogam was non-diagnostic.Furthermore,CMR provides an accurate assessment of total LV mass which is a more robust marker of hypertrophy,with potential implications for risk stratification.In addition,with the intravenous administration of gadolinium,first-pass perfusion sequences can identify myocardial perfusion abnormalities,while late gadolinium enhancement sequences can identify areas of myocardial fibrosis/scarring.Although the clinical implications of late gadolinium enhancement in HCM are still uncertain this information may,in the near-future,have important implications with regard to identifying HCM patients at high risk of sudden death and progressive heart failure,including evolution into the end-stage phase of HCM.Therefore,at present,CMR provides important information impacting on diagnosis and clinical management strategies in patients with HCM and will likely have an expanding role in the evaluation of patients with this complex disease.     

Cardiovascular magnetic resonance and the evaluation of heart failure

Cardiovascular magnetic resonance (CMR) has established itself as probably the single best way of phenotyping the failing heart. It is the accepted gold standard for measuring cardiac function, volumes, and mass, but within the same scan session additional techniques are available for greater definition. Tissue characterization with the contrast agent gadolinium is well validated and allows the precise visualization and quantification of myocardial infarction. This can be used for viability assessment and to determine heart failure etiology. Dobutamine stress CMR and CMR perfusion hold advantages over conventional techniques. The new frontiers of CMR in heart failure hold the promise of unique insights quantifying myocardial iron, nonischemic fibrosis, microvascular perfusion, plaque characterization, and CMR-targeted intervention. The development and validation of these techniques represent major research challenges for the future. From a clinical perspective, an equal challenge is in increasing the availability of the modality for patients and physicians.     

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.     

CMR in Evaluating Valvular Heart Disease: Diagnosis,Severity, and Outcomes

Cardiac magnetic resonance (CMR) is a versatile imaging tool that brings much to the assessment of valvular heart disease. Although it is best known for myocardial imaging (even in valve disease), it provides excellent assessment of all 4 heart valves, with some distinct advantages, including a free choice of image planes and accurate flow and volumetric quantification. These allow the severity of each valve lesion to be characterized, in addition to optimal visualization of the surrounding outflow tracts and vessels, to deliver a comprehensive package. It can assess each valve lesion separately (in multiple valve disease) and is not affected by hemodynamic status. The accurate quantitation of regurgitant lesions and the ability to characterize myocardial changes also provides an ability to predict future clinical outcomes in asymptomatic patients. This review outlines how CMR can be used in cardiac valve disease to compliment echocardiography and enhance the patient assessment. It covers the main CMR methods used, their strengths and limitations, and the optimal way to apply them to evaluate valve disease.     

Cardiac Imaging Integration in 2009 and Beyond: Cardiovascular magnetic resonance

Cardiovascular magnetic resonance (CMR) is currently well recognized in clinical practice for the diagnosis and management of cardiovascular diseases. CMR is helpful in the diagnosis and prognosis of patients with myocardial infarction. The high spatial resolution of CMR enables accurate assessment of tissue characterization in various types of cardiomyopathy. In addition, CMR may play a complementary role with echocardiography in clinical evaluation of patients with valvular and congenital heart disease.     

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.     

A clinical cardiovascular magnetic resonance service: operational considerations and the basic examination

Cardiovascular magnetic resonance (CMR) is now considered the "gold standard" for the assessment of regional and global systolic function, myocardial infarction and viability, and congenital heart disease. At specialized centers, CMR has become a clinical workhorse for the evaluation of ischemic heart disease and for heart failure and cardiomyopathies. Despite this versatility, general acceptance of CMR in cardiovascular medicine has progressed slowly. This article provides a basic understanding of important operational considerations when starting a CMR service and describes a conceptual framework of the components of a CMR examination.     

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.     

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 valvular heart disease by cardiovascular magnetic resonance imaging: a review

CMR is a comprehensive non-invasive tool capable of evaluating all aspects of valvular heart disease. It has advantages over echo including direct quantification of regurgitant lesions, highly accurate assessment of ventricular size and function, visualisation myocardial scar, and interrogation of extracardiac abnormalities. Although these gains can be realised with current scanning techniques, CMR's full potential has yet to be realised, and further studies of clinical outcomes are needed before CMR data can be integrated into the management algorithms for patients with significant valvular lesions.     

Assessment of non-ST-segment elevation acute coronary syndromes with cardiac magnetic resonance imaging

OBJECTIVES: The goal of this study was to determine: 1) if the presence of significant coronary stenosis in patients presenting with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) can be predicted by cardiac magnetic resonance (CMR) imaging; and 2) if the analysis of several CMR methods improves its diagnostic yield compared with analysis of individual methods. BACKGROUND: With modern acquisition techniques, several CMR methods for the assessment of coronary artery disease (CAD) can be combined in a single noninvasive scanning session. Such a multicomponent CMR examination has not previously been applied to a large patient population, in particular those with a high prevalence of CAD in an acute situation. METHODS: Sixty-eight patients presenting with NSTE-ACS underwent CMR imaging of myocardial function, perfusion (rest and adenosine-stress), viability (by late contrast enhancement), and coronary artery anatomy. Visual analysis of CMR was carried out. First, all CMR data were reviewed in combination ("comprehensive analysis"). In further separate analyses, each CMR method was analyzed individually. The ability of CMR to detect coronary stenosis >/=70% on X-ray angiography was determined. RESULTS: Comprehensive CMR analysis yielded a sensitivity of 96% and a specificity of 83% to predict the presence of significant coronary stenosis and was more accurate than analysis of any individual CMR method; CMR was significantly more sensitive and accurate than the Thrombolysis In Myocardial Infarction risk score (p < 0.001). CONCLUSIONS: Cardiac magnetic resonance imaging accurately predicts the presence of significant CAD in patients with NSTE-ACS. In this study, a comprehensive analysis of several CMR methods improved the accuracy of the test.     

When to order cardiovascular magnetic resonance in adults with congenital heart disease

Cardiovascular magnetic resonance (CMR), where available, contributes to the informed management of patients with congenital heart disease. In contrast to echocardiography, CMR becomes easier as patients grow. It is versatile and gives unrestricted access to the heart and intrathoracic vessels, providing functional and structural information. Its relative strengths are discussed, and examples are given of congenital conditions in which it provides clinically important information. CMR can prevent the need for diagnostic catheterization or expedite intervention if indicated, enabling planned, directed procedures. In our practice, CMR is used for serial follow-up, investigation of altered symptoms or signs, planning of transcatheter or surgical interventions, and for baseline assessment after surgery. As CMR becomes more widely available, it will contribute increasingly to the lifelong management of patients with congenital heart disease.     

Volume measurement by CARTO compared with cardiac magnetic resonance.

AIMS: The CARTO electrophysiological mapping system has demonstrated accurate results for end-diastolic ventricular volumes in casts and animals. However, in humans, a comparison with cardiac magnetic resonance (CMR), the non-invasive gold standard for volumetric analysis, has not yet been performed. METHODS AND RESULTS: A total of 34 (29 male) heart failure patients (NYHA class III/IV) underwent an electrophysiological mapping procedure with the CARTO system in the left ventricle (LV) (n = 34) and right ventricle (RV) (n = 12) and CMR for RV and LV end-diastolic volume (RVEDV and LVEDV) measurements another day. Mean LVEDV was comparable between CMR and CARTO (328 +/- 95 and 320 +/- 92 mL, respectively; P = NS), whereas RV volumes measured by CARTO were larger (CMR 140 +/- 48 vs. CARTO 176 +/- 47 mL; P < 0.01). Overall, we found a good correlation between CMR and CARTO measurements for both chambers; however, the Bland-Altman analysis showed a non-interchangeability of these methods. Measurement differences were independent of chamber size, but significantly affected by the number of acquired mapping points. CONCLUSION: Although CMR and CARTO showed a good correlation in the measurement of RVEDV and LVEDV in a group of heart failure patients, the clinical interchangeability of the two methods may be questioned.     

The Role Of Cardiac Magnetic Resonance In Valvular Heart Disease

The prevalence of valvular heart disease is increasing as the population ages. In diagnosing individuals with valve disease, echocardiography is the primary imaging modality used by clinicians both for initial assessment and for longitudinal evaluation. However, in some cases cardiovascular magnetic resonance has become a viable alternative in that it can obtain imaging data in any plane prescribed by the scan operator, which makes it ideal for accurate investigation of all cardiac valves: aortic, mitral, pulmonic, and tricuspid. In addition, CMR for valve assessment is noninvasive, free of ionizing radiation, and in most instances does not require contrast administration. The objectives of a comprehensive CMR study for evaluating valvular heart disease are threefold: (1) to provide insight into the mechanism of the valvular lesion (via anatomic assessment), (2) to quantify the severity of the valvular lesion, and (3) to discern the consequences of the valvular lesion     

Role of Cardiac Magnetic Resonance Imaging in Valvular Heart Disease: Diagnosis,Assessment, and Management

Purpose of Review

This article will review the current techniques in cardiac magnetic resonance imaging (CMR) for diagnosing and assessing primary valvular heart disease.

Recent Findings

The recent advancements in CMR have led to an increased role of this modality for qualifying and quantifying various native valve diseases. Phase-contrast velocity encoded imaging is a well-established technique that can be used to quantify aortic and pulmonic flow. This technique, combined with the improved ability for CMR to obtain accurate left and right ventricular volumetrics, has allowed for increased accuracy and reproducibility in assessing valvular dysfunction. Advancements in CMR technology also allows for improved spatial and temporal resolution imaging of various valves and their regurgitant or stenotic jets. Therefore, CMR can be a powerful tool in evaluation of native valvular heart disease.

Summary

The role of CMR in assessing valvular heart disease is growing and being recognized in recent guidelines. CMR has the ability to assess valve morphology along with qualifying and quantifying valvular disease. In addition, the ability to obtain accurate volumetric measurements may improve more precise management strategies and may lead to improvements in mortality and morbidity.