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.

     

Edema and fibrosis imaging by cardiovascular magnetic resonance: How can the experience of Cardiology be best utilized in rheumatological practice?

Objectives

CMR, a non-invasive, non-radiating technique can detect myocardial oedema and fibrosis.

Method

CMR imaging, using T2-weighted and T1-weighted gadolinium enhanced images, has been successfully used in Cardiology to detect myocarditis, myocardial infarction and various cardiomyopathies.

Results

Transmitting this experience from Cardiology into Rheumatology may be of important value because: (a) heart involvement with atypical clinical presentation is common in autoimmune connective tissue diseases (CTDs). (b) CMR can reliably and reproducibly detect early myocardial tissue changes. (c) CMR can identify disease acuity and detect various patterns of heart involvement in CTDs, including myocarditis, myocardial infarction and diffuse vasculitis. (d) CMR can assess heart lesion severity and aid therapeutic decisions in CTDs.

Conclusion

The CMR experience, transferred from Cardiology into Rheumatology, may facilitate early and accurate diagnosis of heart involvement in these diseases and potentially targeted heart treatment.     

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.)     

The Emerging Role of Cardiac Magnetic Resonance Imaging in the Evaluation of Patients with HFpEF

Purpose of Review

To give an update on the emerging role of cardiac magnetic resonance imaging in the evaluation of patients with heart failure with preserved ejection fraction (HFpEF). This is important as the diagnosis of HFpEF remains challenging and cardiac imaging is pivotal in establishing the function of the heart and whether there is evidence of structural heart disease or diastolic dysfunction. Echocardiography is widely available, although the gold standard in quantifying heart function is cardiac magnetic resonance (CMR) imaging.

Recent Findings

This review includes the recently updated 2016 European Society of Cardiology guidelines on diagnosing HFpEF that define the central role of imaging in identifying patients with HFpEF. Moreover, it includes the pathophysiology in HFpEF, how CMR works, and details current CMR techniques used to assess structural heart disease and diastolic function. Furthermore, it highlights promising research techniques that over the next few years may become more used in identifying these patients.

Summary

CMR has an emerging role in establishing the diagnosis of HFpEF by measuring the left ventricular ejection fraction (LVEF) and evidence of structural heart disease and diastolic dysfunction.

     

Cardiac magnetic resonance in outpatients in Germany--indications, complications and protocol suggestions from a high-volume center

BACKGROUND: Cardiac magnetic resonance (CMR) has developed into a routine examination in many centers in cardiology. However, there is little knowledge about its applicability in outpatients as a diagnostic tool for cardiovascular diseases. We report about the experiences in a high-volume cardiac imaging center and in a "mobile setting" in Germany and provide routinely used examination protocols. METHODS: 8976 patients referred for CMR from cardiologists, internal medicine practices and from general practitioners and 2200 patients examined in a "mobile" system by outpatient cardiologists were included in the study. Indications were as follows: 7672 (69%) examinations for myocardial ischemia and viability, 1313 (12%) for cardiac and pericardial inflammatory disease and cardiac mass, 976 (9%) for detection and quantification of heart valve disease and 466 (4%) for congenital heart disease. 697 (6%) were referred for other indication. Two independent readers performed image analysis of the 8976 patients in our center. RESULTS: Image quality was rated "excellent" in 90.6%, "good" in 8%, "fair" in 1.2% and "poor" in 0.2%. 0.0002% of all examinations were not assessable due to low image quality. Minor complications (temporarily, asymptomatic AV-blockade; mild chest pain and/or dyspnea; nausea) could be observed in 12% and resolved within few minutes. One patient experienced a grand mal seizure due to hyperventilation. 0.9% examinations had to be terminated untimely due to claustrophobia. CONCLUSION: CMR in outpatients is a widely used imaging modality in cardiology in Germany. A large variety of clinical questions may be answered by CMR with excellent image quality and without major complication. With user-adapted protocols, a rapid diagnosis is achieved even in outpatients in a "mobile" setting. Hence, CMR will increase its applicability as a routine imaging tool.     

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.     

Magnetic resonance imaging in the assessment of valvular heart disease

Although Doppler echocardiography remains the most frequently used imaging modality for assessing valvular heart disease, the technique has a number of limitations that could affect the quality of imaging studies and make the results difficult to interpret. Cardiac magnetic resonance (CMR) imaging could be superior to echocardiography in a number of ways: for example, for assessing ventricular dimensions, volumes, function and mass, for quantifying valvular regurgitation, and for investigating areas of myocardial fibrosis and extracardiac structures. In carrying out these tasks, CMR uses a variety of pulse sequences that are specially created to obtain information on specific tissue characteristics or on particular aspects of blood flow through heart valves. This general review article focuses on the usefulness of CMR in the clinical diagnosis of valvular heart disease and reviews how the data acquired using the technique can be incorporated into algorithms for the clinical management of patients with significant valvular heart lesions.     

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.     

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.     

Cardiovascular magnetic resonance imaging for valvular heart disease

Valvular heart disease (VHD) is a clinically important diagnosis, with significant associated morbidity and mortality. Multiple imaging modalities exist to characterize valvular and associated cardiac anatomy. Cardiovascular magnetic resonance (CMR) has emerged as a comprehensive noninvasive imaging modality for VHD. With use of well-established, standardized imaging sequences, CMR can accurately and precisely diagnose valvular structural abnormalities, assess severity of regurgitant and stenotic lesions, and potentially define patient prognosis. This article reviews the clinical applications of CMR in assessment of VHD.     

Midwall myocardial fibrosis in Becker-Kiener muscular dystrophy

Summary We report on a 38- year-old man with Becker-Kiener muscular dystrophy (BMD) and dilated cardiomyopathy without clinical symptoms of congestive heart failure who was referred for risk evaluation of sudden cardiac death. The degree of cardiac involvement in BMD varies greatly from no or hardly any cardiac abnormality to severe arrhythmias, dilatative cardiomyopathy and heart failure to heart transplantation or sudden cardiac death. These cardiac abnormalities have been related to replacement of the cardiomyocytes by connecting tissue or fat. In the clinical setting, cardiovascular magnetic resonance (CMR) has been proved to be a valid non-invasive method for obtaining anatomical and structural information of the heart. Furthermore, gadolinium-enhanced CMR can also characterize areas of myocardial fibrosis. Demonstration of extensive areas of fibrosis in an early stage of the disease might be a surrogate marker for an impaired clinical outcome. Therefore, serial CMR examinations starting upon diagnosis of the disease should be considered, as this may lead to an earlier recognition of cardiac involvement and may affect further management of the patient.     

The emerging clinical role of cardiovascular magnetic resonance imaging

Starting as a research method little more than a decade ago, cardiovascular magnetic resonance (CMR) imaging has rapidly evolved to become a powerful diagnostic tool used in routine clinical cardiology. The contrast in CMR images is generated from protons in different chemical environments and, therefore, enables high-resolution imaging and specific tissue characterization in vivo, without the use of potentially harmful ionizing radiation.CMR imaging is used for the assessment of regional and global ventricular function, and to answer questions regarding anatomy. State-of-the-art CMR sequences allow for a wide range of tissue characterization approaches, including the identification and quantification of nonviable, edematous, inflamed, infiltrated or hypoperfused myocardium. These tissue changes are not only used to help identify the etiology of cardiomyopathies, but also allow for a better understanding of tissue pathology in vivo. CMR tissue characterization may also be used to stage a disease process; for example, elevated T2 signal is consistent with edema and helps differentiate acute from chronic myocardial injury, and the extent of myocardial fibrosis as imaged by contrast-enhanced CMR correlates with adverse patient outcome in ischemic and nonischemic cardiomyopathies.The current role of CMR imaging in clinical cardiology is reviewed, including coronary artery disease, congenital heart disease, nonischemic cardiomyopathies and valvular disease.     

Bringing MRI to the cardiologist: Can we learn from echocardiography?

Cardiac MRI (CMR) is a low-risk, comprehensive diagnostic tool that has many similarities with echocardiography. It is noninvasive, lacks ionizing radiation, and the contrast material used to enhance various images does not have any renal toxicity. Although extremely valuable in the diagnosis of neurologic and musculoskeletal diseases for more than two decades, CMR has only recently become relevant for diagnosing the rapidly beating and constantly mobile heart. Through advances in cardiac gating and high-speed acquisition software, CMR is positioning itself as a critical utensil at the cardiovascular disease banquet. However, like echocardiography, currently celebrating its 50th birthday, CMR is likely to suffer occasional growing pains, along with its share of accomplishments. Therefore, those practicing CMR should learn from the past errors and achievements of echocardiography in an effort to deliver the most rewarding diagnostic instrument imaginable, without having to wait 50 years.     

Indications,safety and image quality of cardiovascular magnetic resonance: Experience in > 5,000 North American patients

Background

CMR offers accurate assessment of structure and function with high resolution. Although the use of CMR has been well established in Europe, information is lacking for the extent of this emerging modality in North America.

Objectives

This study aimed to summarize indications, safety, image quality, extent of contrast use and extent of stress tests performed in a high-volume CMR centre.

Methods

Consecutive patients scanned from July 2005 to November 2010 were included, with duplicates and research subjects removed. Original clinical referrals were categorized into 10 main indications.

Results

Retrospective analysis was performed on 6463 patients (mean ± SD age = 50 ± 17). The most common clinical indications were non-ischemic cardiomyopathies (28%), including myocarditis (18%), coronary artery disease (17%), ARVD and/or other RV disease (12%), and congenital heart disease (11%). Gadolinium-based contrast was given to 89.5% of patients as part of their CMR protocol. Of 10.9% (703/6463) of patients that underwent stress CMR, adenosine was administered most commonly. Of 703 patients, 1 (0.14%) suffered ventricular tachycardia during adenosine stress, and transient, asymptomatic AV block was occasionally observed. Moderate to severe complications after contrast agent administration occurred in 9 (0.16%) of 5782 contrast-enhanced studies, characterized by nausea and vomiting in 6 (0.12%) and by symptoms of acute systemic allergic reaction in 2 (0.04%). Image quality was good (82.0%), moderate but diagnostic (16.6%) and poor in 1.4% of cases.

Conclusion

In the high-volume CMR centre, main clinical indications were for myocarditis/cardiomyopathies, coronary artery disease and RV-related queries. CMR showed an excellent safety profile and high image quality in 99% of cases.     

The role of cardiovascular magnetic resonance in adults with congenital heart disease

The comprehensive coverage and versatility of cardiovascular magnetic resonance (CMR), providing functional as well as anatomical information, make it an important facility in a center specializing in the care of adults with congenital heart disease. Imaging specialists using CMR to investigate acquired heart disease should also be able to recognize and evaluate previously unsuspected congenital malformations. Conditions that may present or be picked up during imaging in adulthood include atrial septal defect, anomalously connected pulmonary veins, double-chambered right ventricle, congenitally corrected transposition of the great arteries, aortic coarctation, and patent arterial duct. To realize its full potential and to avoid pitfalls, CMR of adults with congenital heart disease requires specific training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, after transposition of the great arteries, and after Fontan operations. For these and other more complex cases, CMR should ideally be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients in a tertiary referral center.     

The role of cardiovascular magnetic resonance in the evaluation of valve disease

Echocardiography is the primary imaging modality for initial assessment and longitudinal evaluation of patients with valvular heart disease. Cardiovascular magnetic resonance (CMR) has emerged as an additional or alternative modality in these patients providing clinically useful information not only about the valve lesion itself but also about the consequences for the relevant ventricle. Other unique capabilities of CMR include the assessment of surrounding anatomy (eg, great vessels) and the evaluation of myocardial scar or fibrosis. This review will highlight the role of CMR in the assessment of patients with valve disease with particular emphasis on the advantages of this imaging modality in key areas.     

Midwall myocardial fibrosis in Becker-Kiener muscular dystrophy

We report on a 38- year-old man with Becker-Kiener muscular dystrophy (BMD) and dilated cardiomyopathy without clinical symptoms of congestive heart failure who was referred for risk evaluation of sudden cardiac death. The degree of cardiac involvement in BMD varies greatly from no or hardly any cardiac abnormality to severe arrhythmias, dilatative cardiomyopathy and heart failure to heart transplantation or sudden cardiac death. These cardiac abnormalities have been related to replacement of the cardiomyocytes by connecting tissue or fat. In the clinical setting, cardiovascular magnetic resonance (CMR) has been proved to be a valid non-invasive method for obtaining anatomical and structural information of the heart. Furthermore, gadolinium-enhanced CMR can also characterize areas of myocardial fibrosis. Demonstration of extensive areas of fibrosis in an early stage of the disease might be a surrogate marker for an impaired clinical outcome. Therefore, serial CMR examinations starting upon diagnosis of the disease should be considered, as this may lead to an earlier recognition of cardiac involvement and may affect further management of the patient.     

Ischemic heart disease: comprehensive evaluation by cardiovascular magnetic resonance

Considerable technical advances over the past decade have increased the clinical application of cardiovascular magnetic resonance (CMR) imaging. A comprehensive CMR examination can accurately measure left and right ventricular size and function, identify the presence and extent of reversible versus irreversible myocardial injury, and detect inducible ischemia. Streamlined protocols allow such a CMR examination to be a time-efficient diagnostic tool in patients with coronary artery disease. Moreover, edema imaging with T2-weighted CMR allows the detection of acute coronary syndromes. In this review, we present the relevant CMR methods and discuss practical uses of CMR in acute and chronic ischemic heart disease.