Magnetic resonance imaging in valvular heart disease

Magnetic resonance techniques can be employed to depict valvular abnormalities but are especially helpful in quantifying regurgitant or stenotic lesions which cannot be quantitatively assessed by other noninvasive techniques. Gradient echo techniques and phase velocity mapping are the most important magnetic resonance pulse sequences employed for these purposes. Valvular regurgitation can be quantitated by measuring the area of signal void on conventional gradient-echo images, by calculating stroke volume differences from k-space segmented gradient echo images, by measuring the proximal convergence zone from velocity encoded images or by comparing stroke volumes of the ventricles from velocity measurements. In contrast to this variety of possibilities in regurgitant lesions, stenotic lesions can only be quantitated by using velocity mapping techniques. Magnetic resonance spectroscopy can be used to assess myocardial metabolism in chronic valvular lesions. However, this tool needs further development and more clinical data before its use can be recommended to assess the necessity and optimal timing of surgical intervention.     

Computed tomography and magnetic resonance imaging of patients with valvular heart disease

Although computed tomographic (CT) and magnetic resonance (MR) evaluation of patients with valvular heart disease is almost never performed as a first line of diagnostic intervention, their performance does provide important morphologic and physiologic information concerning the etiology and the current status of the valvular dysfunction. Evaluation of chamber and great artery size as well as ventricular wall thickness provide the basis for diagnosing and analyzing severity of valvular heart disease. Furthermore, additional findings, including calcification and evidence of interstitial pulmonary edema, increase diagnostic sensitivity and confidence in diagnosis. MR examination has the advantage over CT of providing direct demonstration of the signal void jets of dysfunctional valves, as well as a means of quantitating regional and global ventricular function and severity of valvular pressure gradients.     

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.     

Cardiovascular magnetic resonance imaging

Recent advancements in magnetic resonance imaging hardware and software permit the assessment of cardiovascular structure and function at rest and during exercise or pharmacology-induced cardiac stress. With these developments, knowledge of cardiovascular imaging protocols in the magnetic resonance imaging environment is critical for nursing personnel. The purpose of this article is to review information pertinent to working in a magnetic resonance imaging environment and to describe the requirements of nursing personnel performing cardiovascular magnetic resonance imaging examinations.     

Imaging and quantifying valvular heart disease using magnetic resonance techniques

Opinion statement Echocardiography remains the cornerstone of noninvasive valvular heart disease evaluation. There are instances where MRI can be of use. Aside from the obvious advantage where limited acoustic windows are present, cardiac magnetic resonance (CMR) allows for imaging in any desired plane, and advantage can be taken of the ability to align with any regurgitant or stenotic flow jet. The high spatial resolution and contrast allow for accurate detail of valvular anatomy, but it must be remembered that the images represent a composite of eight to 12 heart cycles. For visualizing multiple valvular abnormalities simultaneously, cardiac MRI has a distinct advantage. Finally, a CMR valvular examination can be combined with accurate assessments of left and right ventricular function, myocardial stress perfusion imaging, and detailed viability determinations in a single examination. This provides a comprehensive presurgical evaluation of cardiac physiology.     

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.     

Cardiovascular imaging with nuclear magnetic resonance

This article provides some examples of what the previous article outlined. The sections on Image Display and Myocardial Characterization contain numerous illustrations of gating, cross-sectional images, flow signals, and ischemic injury. The possibility of metabolic imaging with NMR and quantitating blood flow is also considered.     

Cardiovascular magnetic resonance imaging in myocarditis

Cardiovascular magnetic resonance imaging (CMR) has become the leading modality in noninvasive imaging of myocarditis. Consensus on the use of 3 CMR criteria for myocarditis, referred to as edema, early, and late enhancement, has standardized CMR protocol for assessing myocarditis. Although definite diagnosis of myocarditis remains challenging, the outcome of this disease necessitates further investigation with the objective of providing robust noninvasive tests. Moreover, relative to current tools such as endomyocardial biopsy, CMR is a promising technique in the setting of this insidious and complex disease.     

Clinical evaluation of regurgitant blood flow by rapid cine magnetic resonance imaging in patients with valvular heart disease

The clinical usefulness of magnetic resonance imaging (MRI) for evaluating regurgitant blood flow in patients with valvular heart disease was studied. The study subjects comprised three healthy volunteers and nine patients with valvular heart disease (aortic regurgitation 3, mitral regurgitation 2, tricuspid regurgitation 2, and pulmonary regurgitation 2). Five were men and seven were women, ranging in age from 31 to 85 years. Valvular heart disease was diagnosed by two-dimensional Doppler echocardiography. MRI was performed using a 1.5 tesla super-conductive magnet system (MAGNETOM, Siemens AG). A rapid MRI technique (fast low-angle shot [FLASH], flip angle = 30 degrees, TR = 65-90 msec, TE = 10-38 msec) was used to generate 11 frames throughout one cardiac cycle in the transaxial, coronal and oblique planes. These sequential frames were displayed in cine mode on a CRT. 1. Intracavitary blood was imaged as a high signal intensity on gradient echo images, while surrounding cardiac structures had somewhat lower signal intensities. 2. In healthy volunteers, systolic ejection blood flow from the left ventricle was observed on coronal images in the cine mode display. The influx of atrial blood into the left and right ventricles was also clearly observed on transaxial cine images. 3. Aortic regurgitant flow was observed as areas of no signal intensity within the left ventricular cavity during diastole on coronal images. 4. Mitral and tricuspid regurgitations were observed within the left and right atria, respectively, as areas of no signal intensity on transaxial images. The extent of regurgitant flow was determined in the vertical long-axis plane, equivalent to the right anterior oblique projection. 5. The vertical oblique scan was suitable for detecting pulmonary regurgitant flow. These results indicate that the rapid cine MRI technique is a useful tool for noninvasively determining regurgitant blood flow in patients with various valvular heart diseases.     

Assessing left atrial function in patients with atrial fibrillation and valvular heart disease using cardiovascular magnetic resonance imaging

BackgroundAtrial fibrillation (AF) is common arrhythmia in valvular heart disease (VHD) and is associated with adverse outcomes.HypothesisTo evaluate the left atrial (LA) function in patients with AF‐VHD by cardiovascular magnetic resonance imaging feature tracking (CMR‐FT) using LA strain (ε _s/ε _e/ε _a) and their corresponding strain rate (SRs/SRe/SRa).MethodsThis was a retrospective cross‐sectional inter‐reader and intra‐reader reproducibility conducted from July 1, 2020, to January 31, 2021. A total of 39 patients with AF‐VHD (rheumatic heart valvular disease [RHVD] [n = 22], degenerative heart valvular disease [DHVD] [n = 17]) underwent MRI scans performed with drug‐controlled heart rate before correcting the rhythm and valves through maze procedure. Fifteen participants with normal cardiac MRI were included as healthy control. ε _s/SRs, ε _e/SRe, and ε _a/SRa, corresponding to LA reservoir, conduit, and booster‐pump function, were assessed using Feature Tracking software (CVI42 v5.12.1).ResultsCompared with healthy controls, LA global strain parameters (ε _s/ε _e/ε _a/SRs/SRe/SRa) were significantly decreased (all p < 0.001), while LA size and volume were increased in AF‐VHD group (all p < 0.001). In the subgroup, RHVD group showed lower LA total ejection fraction (LATEF) and strain data than DHVD group (12.6% ± 3.3% vs. 19.4 ± 8.6, p = 0.001). Decreased LATEF was significantly related to altered LA strain and strain rate, especially in ε _s, ε _e, and SRs (Pearson/Spearman r/ρ = 0.856/0.837/0.562, respectively; all p < 0.001). Interstudy and intrastudy reproducibility were consistent for LA volumetry and strain parameters (intraclass correlation coefficient: 0.88–0.99).ConclusionsCMR‐FT can be used to assess the LA strain parameters, and identify LA dysfunction and deformation noninvasively, which could be a helpful functional imaging biomarker in the clinical treatment of AF‐VHD.     

Assessment of blood flow and valvular heart disease using phase-contrast cardiovascular magnetic resonance

Measurement of blood flow is important for assessing the severity of disease processes involving the cardiovascular system. Phase-contrast cardiovascular magnetic resonance (PC-CMR) can be used to measure blood flow noninvasively without ionizing radiation or limitations imposed by body habitus. This review describes the performance of PC-CMR and its clinical utility in assessing patients with cardiovascular or valvular heart disease.     

Cardiovascular magnetic resonance imaging in hypertrophic cardiomyopathy

The use of cardiovascular magnetic resonance in patients with hypertrophic cardiomyopathy over the last decade has helped elucidate the diagnosis, prognosis, pathophysiology, and management of this disease. Studies have shown that the use of magnetic resonance imaging in a patient with a permanent pacemaker and implantable cardioverter defibrillator is safe.     

Cardiovascular magnetic resonance imaging for amyloidosis: The state-of-the-art

Amyloidosis results from insoluble precursor proteins being deposited in the extracellular compartment. The prognosis of the disease is predominantly determined by cardiac involvement due to amyloid accumulation that contributes to cardiac dysfunction and disturbed conduction of cardiac electrical signals. The clinical and radiological manifestations of amyloidosis are often non-specific, making amyloidosis a diagnostic challenge both for clinicians and radiologists. Cardiovascular magnetic resonance imaging, including conventional sequences, late gadolinium enhancement, T1 mapping and determination of extracellular volume fraction is a multi-dimensional modality for the assessment and diagnosis of cardiac amyloidosis and, in addition, is an excellent tool for risk stratification and disease tracking.     

Quantification of valvular aortic stenosis by magnetic resonance imaging

Background Assessing the aortic valvular orifice is important in judging the severity of aortic stenosis. Magnetic resonance imaging visualizes in-plane valvular motion. We studied the value of magnetic resonance planimetry of the aortic valve orifice. Methods We used breath-hold gradient echocardiographic sequences on a clinical magnetic resonance system (1.5 T) and studied 25 patients with symptomatic valvular aortic stenosis. We performed a planimetry of the valvular orifice in systolic images of the valvular plane. The results were compared with echocardiography (continuity equation) and cardiac catheterization (Gorlin formula). Results Magnetic resonance planimetry was feasible in all patients, and the image quality was invariably adequate. The magnetic resonance imaging results correlated well with the data calculated from catheterization and less robustly with the echocardiographic results. The 3 methods were similar in terms of leading to clinical decisions. Conclusions We suggest that magnetic resonance flow planimetry of the aortic valve orifice offers a simple, reliable, fast, and safe method to noninvasively quantify aortic stenosis. (Am Heart J 2002;144:329-34.)     

Role of cardiac magnetic resonance imaging in ischaemic heart disease

Cardiac magnetic resonance imaging is a new imaging method that has much to offer clinicians caring for patients with ischaemic heart disease. This article describes briefly the basic principles and practical aspects of cardiac magnetic resonance imaging, and summarizes the pathophysiology of ischaemic heart disease. Then it discusses in detail the use of cardiac magnetic resonance imaging for detection of coronary artery disease, and for assessment of acute and stable coronary syndromes.