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Cardiomyopathies (CMPs) include dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) (1). Other forms of acute and chronic nonischemic myocardial diseases have been detected, with stress-induced CMP and noncompaction CMP the most vividly discussed. [ABSTRACT FROM AUTHOR]

Interventional cardiovascular magnetic resonance imaging (iCMR) is potentially revolutionary because of the exquisite tissue and blood imaging afforded to guide therapeutic procedures. By making small compromises in spatial or temporal resolution, and with little or no modifications to commercial high-performance magnetic resonance imaging (MRI) systems, images can be acquired and displayed almost instantaneously to operators. This may be useful simply to avoid ionizing radiation during conventional catheter-based procedures, especially in children. Perhaps more important, iCMR promises to enable more advanced procedures not otherwise possible without open surgical exposure. [ABSTRACT FROM AUTHOR]

Although some of the energy of left ventricular contraction produces forward blood flow during systole, the majority is briefly stored as potential energy in the distended arteries. During diastole, this energy is then reconverted into forward flow as the arteries contract (1,2). This serves to ease the load on the left ventricle, promote coronary artery perfusion, and maintain forward flow to the peripheral vessels. In Otto Frank's original "Windkessel" model (3), the arterial system acts as an elastic chamber in which diastolic pressure decays exponentially with a time constant determined by total arterial resistance and capacitance or compliance. Later refinements to this model include the addition of an inductance, or blood inertia, term and the division of the arterial tree into smaller Windkessel elements in analogy to a transmission line (4,5). Systemic arterial compliance is dominated by the aorta, which contributes over 60% of the total value (6). [ABSTRACT FROM AUTHOR]

Magnetic resonance spectroscopy (MRS) is a multinuclear noninvasive tool that offers a window into myocardial metabolism. This chapter reviews the nuclei typically studied with cardiac MRS and the magnetic resonance (MR) techniques used to acquire spatially localized cardiac spectra. We then review the clinical MRS studies of human myocardial metabolism with emphasis on common clinical conditions such as myocardial ischemia, viability, hypertrophy, and heart failure. [ABSTRACT FROM AUTHOR]

Atherothrombotic cardiovascular disease remains the leading cause of morbidity and mortality in the Western world and is rapidly becoming the number one killer in the developing countries (1). Atherosclerosis is a systemic and progressive disease involving the intima of large- and medium-size arteries, including the aorta and the carotid, coronary, and peripheral arteries. Atherothrombosis, defined as atherosclerotic plaque disruption with superimposed thrombosis, can progress to potential life-threatening conditions, such as myocardial infarction or ischemic stroke. The concept of vulnerable plaque has been introduced to distinguish thrombosis-prone plaques and plaques with a high probability of undergoing rapid progression. More recently, the term vulnerable patient has been proposed in recognition of contributing culprit factors, including vulnerable blood (prone to thrombosis) and vulnerable myocardium (prone to fatal arrhythmia), that identify high-risk patients with high likelihood of developing cardiovascular events in the near future (2). [ABSTRACT FROM AUTHOR]

Advances in cellular and molecular biology are extending the horizons of medical imaging from gross anatomical description toward delineation of cellular and biochemical signaling processes. The emerging fields of cellular and molecular imaging aim to noninvasively diagnose disease based on the in vivo detection and characterization of complex pathological processes, such as induction of inflammation or angiogenesis. Techniques have been developed to achieve molecular and cellular imaging with most imaging modalities, including nuclear (1,2), optical (2,3), ultrasound (4,5), and magnetic resonance imaging (MRI) (6,7). This chapter focuses on methods under development for detection of atherosclerosis and cardiovascular pathology by MRI molecular imaging. In particular, we focus on the growing role of nanotechnology in the development of new diagnostic and therapeutic constructs that can be used with MRI (6,8). [ABSTRACT FROM AUTHOR]

The development of radio-frequency ablation for the treatment of atrial fibrillation has led to increased interest in the accurate determination of pulmonary vein anatomy to help plan the procedure and to monitor for postablation stenosis. Contrast-enhanced magnetic resonance angiography readily demonstrates the pulmonary veins and is the method of choice for these required serial imaging studies. In this chapter, we review the techniques for pulmonary vein imaging, normal and variant pulmonary vein anatomy, the utility of imaging prior to and after atrial fibrillation ablation, and congenital pulmonary vein anomalies. [ABSTRACT FROM AUTHOR]

Magnetic resonance angiography (MRA) has virtually replaced diagnostic conventional X-ray angiography and has become the primary imaging tool for the evaluation of the diseases of the aorta and branches for many indications (1-13). Development of faster magnetic resonance imaging (MRI) scanners with shorter TR (relaxation time) and TE (echo time) and powerful gradients, allowing completion of principal MRA sequences within single breath hold, has led this revolution (2). Improvements in coil, computer hardware/software technology, and postprocessing techniques have also contributed to this transition and made MRA a rapid and robust technique. [ABSTRACT FROM AUTHOR]

Technical advances over the past two decades have greatly expanded the diagnostic role of cardiac magnetic resonance (CMR) imaging in patients with congenital heart disease. In addition to high-resolution anatomical information, CMR provides physiological information about the cardiovascular system, such as ventricular function and blood flow. Along with these improved capabilities, the speed and efficiency of imaging have increased, thereby allowing a comprehensive examination to be obtained within a time frame acceptable to both patient and operator. [ABSTRACT FROM AUTHOR]

Congenital heart disease (CHD) occurs in approximately 8 of every 1000 live births, half of whom require surgical or other forms of treatment. Complex CHD has no precise acceptable definition. For the purposes of this chapter, we define complex CHD to include conotruncal anomalies and single-ventricle heart disease. Conotruncal anomalies refer to a group of congenital heart defects involving the outflow tracts of the heart and the great vessels. Single-ventricle heart disease refers to a heterogeneous group of anomalies in which one of the two ventricular sinuses is absent (anatomical single ventricle) or to hearts with complex anatomy in which biventricular physiology cannot be attained (functional single ventricle). [ABSTRACT FROM AUTHOR]

Cardiovascular magnetic resonance (CMR) imaging can accurately assess cardiac structure and physiology vital in evaluating regurgitant or stenotic valvular heart disease. Its versatility in providing comprehensive anatomical and functional assessment in valvular heart disease stems from its ability to qualitatively and quantitatively measure flow volumes, velocities, and flow fractions in any oblique cardiac plane. [ABSTRACT FROM AUTHOR]

The pericardium consists of the parietal and visceral layers separated by 15-30 mL of serous fluid. The serous visceral layer envelops the heart and several centimeters of the proximal great vessels, where it reflects to form the fibrotic, outer parietal layer. The normal pericardium serves such functions as reducing motion friction between the heart and surrounding structures, maintaining diastolic pressures by confining diastolic expansion of thin-walled cardiac chambers, constraining the bulk cardiac motion in the middle mediastinum, and limiting the spread of infection from the mediastinal structures. However, it is not necessary for normal cardiac function, as shown by patients with a surgically or congenitally absent pericardium. [ABSTRACT FROM AUTHOR]

Primary cardiac and pericardial tumors are rare and affect patients of all ages. Primary cardiac tumors have a reported incidence between 0.0017 and 0.19% in autopsy series (1). Approximately 75% of all cardiac tumors are benign histologically, and the remainder are malignant. Approximately half (52%) of the benign cardiac tumors are myxomas, which account for the most frequent primary cardiac tumor. Other lesscommon benign tumors include papillary fibroelastomas (16%), lipomas (16%), hemangiomas (6%), fibromas (3%), and rhabdomyomas (1%). Less frequently, teratomas, neurofibromas, lymphangiomas, cystic tumors of the atrioventricular node, endocrine tumors (paraganglioma), and histiocytoid tumors comprise the rest of benign tumors (2,3). [ABSTRACT FROM AUTHOR]

Cardiac magnetic resonance imaging (MRI) techniques continue to change rapidly, and cardiac MRI is developing as an alternative noninvasive technique having the unique potential of three-dimensional function analysis with great accuracy and reproducibility. Advances in rapid cardiac MRI technology are making real-time imaging possible at approaching echocardiographic frame rates. Together with the increasing availability of cardiac MRI machines, cardiac MRI has the potential of a powerful and comprehensive tool for the analysis of heart function. In this chapter, the potential role of cardiac MRI in the evaluation of diastolic heart function is reviewed. [ABSTRACT FROM AUTHOR]

Cardiovascular magnetic resonance (CMR) is well suited to assessing patients with myocardial infarction. In a relatively short examination, CMR can assess myocardial anatomy, left ventricular function, perfusion, and viability—all with excellent image quality. Furthermore, the imaging planes can be programmed to provide identical views of the heart for each type of image. This facilitates intermodality comparisons. [ABSTRACT FROM AUTHOR]

The purpose of this chapter is not to produce a list of comparative studies between nuclear-based techniques and the cardiac magnetic resonance (MR) exam. These will change with time. It is rather to look at the two modalities in terms of physical principles and methods to determine where they differ, their degree of difference, where they are similar, and how they may be correlative. Nuclear imaging has had a long life within cardiology, and there is much magnetic resonance imaging (MRI) has to learn from it. It is a waste of resources to repeat the mistakes of the past. Consequently, practitioners of cardiovascular magnetic resonance imaging should have a foundation of the nuclear imaging past and present. The two modalities will certainly compete for the molecular imaging of the future. [ABSTRACT FROM AUTHOR]

Coronary artery disease is one of the leading causes of morbidity and mortality in many industrialized countries (1). Catheter X-ray coronary angiography has been used as the gold standard for identifying significant luminal narrowing of the coronary arteries. However, X-ray coronary angiography entails small but definable risks (2), and a considerable number of patients undergoing elective X-ray coronary angiography are found to have no significant coronary arterial disease (3). Consequently, there is a strong need for a noninvasive test that can reliably delineate narrowing of the coronary arteries. [ABSTRACT FROM AUTHOR]

Although cardiovascular magnetic resonance (CMR) can image myocardial perfusion with many methods, first-pass perfusion studies using gadolinium contrast have the highest signal-to-noise ratio and most extensive published experience. This chapter focuses primarily on the basic principles and clinical applications of first-pass myocardial perfusion studies. [ABSTRACT FROM AUTHOR]

Cardiovascular magnetic resonance (CMR) imaging is increasingly used to detect the presence of coronary artery disease (CAD) and to assess its hemodynamic significance (1). The development of rapid gradient systems and consequently very short measurement times allows us to perform high-resolution cine imaging of the heart at rest and under stress conditions up to heart rates of 200 beats per minute. The standard sequence used today for visualization of cardiac wall motion (steady-state free precession) provides an excellent endocardial border definition independent of limiting acquisition windows because of the high blood-myocardium contrast without the need for application of contrast agents (2). This endocardial border definition is highly superior to state-of-the-art echocardiographic image quality. [ABSTRACT FROM AUTHOR]

In the wake of an acute myocardial infarction (AMI), accurate assessment of the left ventricle (LV) is of paramount importance as functional impairment or chamber dilatation predicts increased mortality (1-3). In a study of 866 postinfarct patients, a resting LV ejection fraction (EF) less than 0.40 predicted higher 1-year mortality than did an LVEF greater than 0.40 (1). Others have demonstrated that, following reperfusion therapy, the relationship between resting LVEF and all-cause mortality persists (4). Although LVEF is a powerful predictor of postinfarct survival, end-systolic volume (ESV) is superior as a prognostic parameter. This was demonstrated by White et al., who enrolled 605 patients following AMI and followed them for an average of 78 months. Ultimately, ESV was the best predictor of survival, and neither the LVEF nor end-diastolic volume (EDV) added prognostic value. [ABSTRACT FROM AUTHOR]

Because of unsurpassed soft tissue resolution, lack of ionizing radiation, and multi-planar imaging capability, magnetic resonance imaging (MRI) has become an important tool in the evaluation and treatment of cardiovascular disorders. However, an increasing proportion of patients with cardiovascular disease have higher acuity of disease and ferromagnetic implants with potential for interaction with the MRI environment. Familiarity with each device class and its potential for electromagnetic interaction is essential for radiologists and cardiologists performing MRI examinations in this population of patients. [ABSTRACT FROM AUTHOR]

The accurate assessment of left ventricular (LV) systolic function is clinically important in nearly all types of cardiac disease and often directly affects patient management. One example in ischemic heart disease include acute myocardial infarction (MI) for which ejection fraction and end-systolic volume are important predictors of survival (1) and are used to determine medical therapy. In other examples, a positive functional response to low doses of dobutamine accurately predicts recovery of function after acute MI and identifies myocardial viability in chronic MI. In the latter case, the functional response to dobutamine can be used to guide coronary revascularization therapy. In addition, the presence or absence of inducible wall motion abnormalities during stress testing indicates the presence or absence of significant coronary artery stenoses and consequently determines whether cardiac catheterization is indicated. Finally, recent research shows that the degree of LV dyssynchrony may be better than QRS morphology or width for predicting the response to cardiac resynchronization therapy in patients with heart failure. [ABSTRACT FROM AUTHOR]

In the last two decades, magnetic resonance imaging (MRI) has revolutionized clinical cardiovascular imaging. Its major advantages over other noninvasive diagnostic modalities are its safety, operator-independent reproducibility, and multiplanar two-dimensional (2D) and three-dimensional (3D) imaging capability with high spatial and temporal resolution. MRI does not deliver ionizing radiation and does not utilize inherently nephrotoxic iodinated contrast media. The intrinsic tissue contrast offered by MRI has been even further expanded by the introduction of paramagnetic magnetic resonance (MR) contrast agents. These agents improve the image signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), thereby increasing the sensitivity, specificity, and accuracy of MRI. [ABSTRACT FROM AUTHOR]

The constant motion of the heart poses great challenges when developing cardiac imaging strategies. There is the beating motion of the heart, rich in clinically relevant information such as wall thickening and ejection fraction, and the respiration-induced motion of the heart, with little clinical importance other than the artifacts it may cause. The most common approach to handle these two types of motion consists of freezing the respiratory motion through breath holding while resolving the beating motion through electrocardiogram (ECG) gating (Chapter 2). Alternatively, one may freeze all motions at once using a suitably short scan time in real-time imaging. When breath holding is used, we need to image fast for patients to comply, and without breath holding, we need to image fast to freeze all motions involved. The need for fast imaging is ever present in cardiac imaging as speed is central to our strategies for handling motion. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) has been increasingly recognized for its role in the diagnosis, treatment planning, and clinical management of patients with cardiovascular disease and has several important advantages over alternative imaging modalities, including electrocardiogram (ECG) synchronized and direct three-dimensional (3D) volumetric imaging unrestricted by imaging depth. In addition, the intrinsic sensitivity of MRI to flow, motion, and diffusion offers the unique possibility to acquire spatially registered functional information simultaneously with the morphological data within a single experiment (1-13,16-19,31,36,38). As a result, flow-sensitive MRI techniques, also known as phase contrast (PC) MRI, provide noninvasive methods for the accurate and quantitative assessment of blood flow or tissue motion. Characterizations of the dynamic components of blood flow and cardiovascular function provide insight into normal and pathological physiology and have made considerable progress (14,15,20-29,35,55). [ABSTRACT FROM AUTHOR]

Outside the field of magnetic resonance imaging (MRI), most techniques for myocardial perfusion imaging rely on the direct detection of injected tracers. Examples are tracers that emit γ-rays for single photon emission tomography or tracers that scatter ultrasound waves, such as injected gas-filled bubbles. With MRI, blood-borne contrast agents can be used to assess myocardial perfusion. The presence of the contrast agent in tissue is detected through the effects of the contrast agent on the signal from 1H nuclei. [ABSTRACT FROM AUTHOR]

Cardiovascular magnetic resonance (CMR) allows for a highly accurate description of segmental wall motion and quantitation of contractile function. The excellent contrast between the endocardium and blood pool improves measurement of wall thickness, end-diastolic and end-systolic volumes, and left ventricular (LV) ejection fraction. Other noninvasive imaging modalities such as echocardiography assume a uniform LV geometry when calculating these global parameters. Errors caused by these assumptions are magnified when the LV shape is deformed, such as in dilated cardiomyopathy or after a myocardial infarction (MI). Because CMR acquires images in a tomographic set of planes, no assumptions regarding LV geometry are made. Not only does CMR produce more accurate global measurements, but also regional function can be precisely quantitated. The purpose of this chapter is to describe the clinical applications of these techniques for assessment of segmental right ventricular (RV) and LV function. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) not only depicts anatomical details, but can be sensitized to the movement and deformation of soft tissues such as the muscle of the heart and can provide measurements of tissue motion at high resolution. A particularly useful class of methods for assessing the contractile function of the myocardial wall is displacement imaging. Magnetic resonance (MR) displacement imaging measures the change of position of tissue elements over a period of time starting from a reference time-point. In concept, it is similar to tracking the three-dimensional (3D) movement of implanted radio-opaque markers in cine fluoroscopy, but instead of using extraneous markers, controlled modulations of various aspects of tissue proton magnetization are utilized as noninvasive markers. Advances in phase modulation techniques allow all pixels of an image to be tracked simultaneously and therefore give high-density measurements of tissue motion. [ABSTRACT FROM AUTHOR]

In patients with heart disease, quantification of left ventricular (LV) function and mass is important for prognosis (1,2). Cardiac magnetic resonance imaging (MRI) measurements of LV function have already been helpful in the prognostic assessment of patients (3). [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) techniques produce high spatial, contrast, and temporal resolution image data for evaluation of cardiac and great vessel anatomy, regional tissue characterization, vascular blood flow, cardiac chamber filling and contraction, regional myocardial dynamics, and myocardial perfusion. MRI produces series of tomographic images of the heart and great arteries in arbitrary section, allowing tailoring of an examination to address a specific clinical problem or a systematic analysis of cardiac structure and physiological function. Recognition of a particular or general abnormality is based on recognition of variance between the instant image data at hand and the expected normal appearance of the heart and great arteries. [ABSTRACT FROM AUTHOR]

Cardiac magnetic resonance imaging (MRI) has many potential advantages over conventional cardiac imaging techniques. These include a lack of ionizing radiation, free choice of imaging planes, the capability for tissue characterization, qualitative and quantitative evaluation of the motion of both the blood and the myocardium, and assessment of regional perfusion. These capabilities have been realized through the implementation of many MRI techniques, which have many associated imaging options. Although this range of options to choose from when performing a cardiac MRI examination can be daunting, it provides a great deal of flexibility that can be used to tailor the examination to the patient and the particular clinical question to be addressed. Some of the current clinical indications for cardiac MRI are summarized in Table 1. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) basic physics can be described at many different levels, ranging from purely descriptive all the way to quantum mechanics. Here, MRI physics is dealt with mostly in a descriptive manner, and simple mathematics are introduced only if necessary. The simple vector-based model for representing the magnetization is presented because it can deal with most aspects of MRI without the additional complexity of quantum mechanics. In this chapter, nuclear magnetic resonance (NMR) signal generation and its properties are discussed first. Subsequently, image formation in terms of localizing the NMR signal in three dimensions is presented. [ABSTRACT FROM AUTHOR]

Current clinical magnetic resonance imaging (MRI) techniques are based on detection of protons (1H) that are bound to mostly water and macromolecules (such as in fat or protein) of the body. 1H is very abundant in the body, and this property provides adequate signal-to-noise ratio for image generation at the magnetic field strengths (B0) of current clinical MRI scanners (1.5 Tesla). The single positively charged proton itself functions much like a tiny tissue magnet inside a magnetic field. When a patient is placed in an MRI scanner, each proton aligns with the magnetic field and spins around its axis (a process known as precession) at a frequency defined by the magnitude of the magnetic field in Tesla. When a given direction and magnitude of the B0 magnetic field are manipulated by applying a secondary magnetic field (radiofrequency pulse), the protons within a part of the body of imaging interest can then be "excited." These excited protons release a specific magnetic resonance signal (known as free induction decay) that contains structural and physical information on the tissues being imaged. To create an MR image, a set of gradient coils in the MRI provides the relevant three-dimensional spatial coordinates (x, y, and z) and detects the intensity of the magnetic resonance signal in each of the coordinates. Utilizing the fast speed of modern computers for data acquisition and digital processing, static or dynamic magnetic resonance images that provide crucial information of tissue functions can be rapidly acquired. [ABSTRACT FROM AUTHOR]