Detection and quantification of valvular heart disease with dynamic cardiac MR imaging

Assessment of valve disease: qualitative and quantitative

Evaluation of valve disease has changed significantly with the development of color Doppler echocardiography. Nevertheless, this technique has limitations, particularly in the assessment of valvular regurgitation. MR imaging, with its ability to provide three-dimensional morphologic data, dynamic cine information, and functional evaluation with flow-sensitive techniques, can be envisioned as a complementary noninvasive modality, able to provide the complete information required for planning therapeutic options. With MR imaging, qualitative as well as accurate and reproducible quantitative information such as volume measurements, cardiac function, and flow velocity profiles are unique for the evaluation of the severity of valve disease. This article reviews the different MR imaging techniques used in assessing valvular heart disease and discusses the advantages and limitations of these techniques in current clinical applications in comparison with classical imaging methods.

MR angiography of the chest

Using the described strategies all relevant disease processes of the thoracic vessels can be fully depicted using contrast-enhanced three-dimensional MRA. The aorta and the major neck and arm vessels are well visualized. Vascular pathologies, such as aneurysms, dissections, and occlusions, are readily recognized. With the implementation of high-performance gradients, three-dimensional MRA of the pulmonary vasculature has become possible even in dyspneic patients. Congenital lesions, such as coarctations, are particularly well suited for analysis with these techniques.

Magnetic resonance imaging of cyanotic and noncyanotic congenital heart disease

MRI has become an important imaging tool that complements echocardiography in the noninvasive evaluation of congenital heart defects. It can play a crucial role in diagnosis by assessing anatomic and functional features in CHD and identifying complications and postoperative sequelae. The performance and application of cardiac MRI require not only knowledge of the clinical question that needs to be addressed but knowledge of the anatomic characteristics of a variety of congenital heart lesions. A knowledge of the advantages and disadvantages of the different imaging sequences also is important so as to optimize and expedite the examination.

Magnetic resonance imaging in coronary heart disease

Modern level of cardiac magnetic resonance imaging (MRI) development already allows its routine use (with proper indications) in coronary heart disease patients for studies of heart morphology and functions, performance of stress tests for evaluation of myocardial perfusion and contractile function. Coronary MRA and some other new MR techniques are close to its wide-scale clinical application. It has been shown that cardiac MRI is a valuable tool for detection of postinfarction scars, aneurysms, pseudoaneurysms, septal defects, mural thrombi and valvular regurgitations. Due to intrinsic advantages of the method it is of special value when these pathological conditions cannot be fully confirmed or excluded with echocardiography. MRI is recognized as the best imaging method for quantification of myocardial thickness, myocardial mass, systolic myocardial thickening, chamber volumes, ejection fraction and other parameters of global and regional systolic and diastolic function. MRI is used in studies of cardiac remodeling in postinfarction patients. The most attractive areas for cardiovascular applications of MRI are assessment of myocardial perfusion and non-invasive coronary angiography. Substantial progress has been achieved in these directions. There are some other new developments in studies of coronary artery disease with MRI. High-resolution MR is used for imaging and quantification of atherosclerotic plaque composition in vivo. Intravascular MR devices suitable for performing imaging-guided balloon angioplasty are created. But before MRI will be widely accepted by the medical community as a important cardiovascular imaging modality several important problems have to be solved. Further technical advances are necessary for clinical implementation of all major diagnostic capabilities of cardiac MRI. The subjective obstacles for growth of clinical applications of cardiac MRI are lack of understanding of its possibilities and benefits both by clinicians and radiologists themselves. So proper training of specialists and promotion of this promising modality among the medical community are necessary.