Cardiovascular magnetic resonance (CMR) is among the most exciting and most advanced of the imaging modalities, and its ability to visualize cardiac structures dynamically represents a true breakthrough in imaging technology. CMR has important real and potential applications for assessing vascular anatomy, the structure and function of the cardiac chambers (including ventricular mass and volume), myocardial perfusion, and myocardial scar.
Many of the applications of CMR are those that can be performed using more readily available and less expensive technology. For example, evaluation of left ventricular mass, shape, volume, and both region and global systolic function are obtained with echocardiography on a routine basis, and radionuclide imaging is in a strong leadership position for myocardial perfusion imaging. CMR is useful for these purposes when either echocardiography or nuclear perfusion imaging is unable to obtain adequate image quality or provides equivocal findings. However, CMR is not relegated to this second-tier position for many other indications in which CMR has been established as the gold standard. Most notably, the ability to visualize myocardial necrosis and fibrosis using late gadolinium hyperenhancement is an attribute that is unique to CMR. Contrast-enhanced CMR accurately identifies the location, transmural and circumferential extent, and mass of infarcted myocardium, in both acute and chronic settings. The detection of even small infarct zones detects previous myocardial infarction in patients in whom this diagnosis cannot be made by other methods. Infarct mass measured shortly after treatment for myocardial infarction predicts the degree of subsequent left ventricular remodeling and thus has important prognostic implications. As a marker of non-viable myocardium, contrast-enhanced CMR is an excellent method for determining the presence or absence of viable myocardium, which predicts the likelihood of reversal of regional and global dysfunction after revascularization.
Another means to assess myocardial viability is imaging regional left ventricular function during low-dose dobutamine administration to demonstrate contractile reserve, and studies have demonstrated that the combination of low-dose dobutamine CMR and contrast-enhanced CMR provides diagnostic accuracy in identifying viable myocardium that is greater than either method alone.
Contrast hyperenhancement has also been observed in a number of other conditions beyond coronary artery disease, including myocarditits, dilated cardiomyopathy, hypertrophic cardiomyopathy, and infiltrative conditions such as amyloidosis and sarcoidosis, which reflect pathophysiologic processes affecting the myocardial extracellular space. In some disorders, detection of these processes has prognostic as well as diagnostic value.
Unlike perfusion imaging with single photon or positron emitting radionuclides, which has limited spatial resolution, CMR perfusion imaging with pharmacologic stress provides information regarding the transmural extent of myocardial ischemia. CMR is thus able to visualize small areas of ischemia (usually present in the subendocardial zone) and also detects subendocardial ischemia in patients with multivessel coronary artery disease who might be misdiagnosed as normal by nuclear imaging because of a uniform, balanced reduction in flow. Similar methods have detected diffuse subendocardial hypoperfusion during vasodilator stress in patients with microvascular abnormalities such as those with syndrome X. New methods have evolved for quantification of regional myocardial blood flow distribution from endocardium to epicardium. Such quantitative methods will be valuable for assessing therapies, such as those stimulating angiogenesis, that result in small increases in endocardial perfusion within the ischemic zones.
CMR has become established as the most accurate noninvasive method for measuring left ventricular mass and volume, and thus ejection fraction measurements also have a high degree of accuracy and reproducibility. Strain imaging using tagging techniques offer exciting possibilities to further the understanding of regional systolic and diastolic function in a variety of cardiac diseases.
Coronary magnetic resonance angiography (MRA) remains an elusive target as a procedure that can yield images of diagnostic quality on a uniform, reproducible basis. The small caliber and tortuosity of the vessels, combined with cardiac and respiratory motion, have presented hurdles that are yet to be surmounted. Nonetheless, progress is being made. In contrast, MRA of the larger and relatively stationary non-coronary vessels is now commonplace in clinical practice, providing excellent visualization of the vessel wall and lumen, with and without the use of contrast media. Arterial remodeling is readily apparent in atherosclerotic vessels with large plaque volumes before there is significant encroachment of the vascular lumen, and important progress has been made in tissue characterization of the atherosclerotic plaques. There is promise that, with further technical advances, similar inroads will be made in coronary MRA and coronary plaque characterization.
One of the major advantages of CMR is the ability to obtain images of such excellent spatial resolution without ionizing radiation. Thus, when future research ultimately achieves the goal of routine, high quality coronary artery imaging, coronary MRA will undoubtedly compete very favorably with coronary CT angiography as the preferred tool for noninvasive assessment of coronary atherosclerotic burden and severity of coronary stenosis.
Other unresolved issues still linger: Who should be studied? Who should interpret the study? Who will pay for the study? Who will train whom? How will guidelines be affected? How will quality be determined and maintained? Hopefully, these are not unresolvable, and the cardiovascular societies are collectively addressing these complex and inter-related questions. Measuring performance in cardiac imaging is inherently difficult as it is not possible to connect the results of an imaging test to health-related outcomes. Patient selection is a key variable as it impacts importantly on downstream management decisions including further testing, interventions and costs.
On the other hand, cardiovascular imaging has transformed, and will continue to transform, cardiovascular care. CMR in particular represents a revolutionary imaging modality that creates a unique opportunity to improve diagnosis and streamline clinical management strategies but also creates challenges in patient selection, clinical training, resource utilization and cost effectiveness. That will be our challenge going forward.
The editorial team of Braunwald's Heart Disease is delighted to launch a series of four imaging companions, each dedicated to one of the key cardiac imaging modalities. This companion on cardiovascular magnetic resonance, expertly edited by Drs. Kramer and Hundley, covers all of the important technical and clinical aspects of this exciting field and provides a unique case-based perspective into the tremendous potential for magnetic resonance imaging to enhance patient diagnosis and management. We believe that this companion will be a highly valuable resource for clinicians, imaging subspecialists and cardiovascular trainees and that it will contribute in a significant manner to the care of the patients they serve.
Key Features
- Key points in each chapter summarize the most important things to remember.
- A case-based format demonstrates how imaging principles apply to real clinical situations.
- A clinically oriented, practical approach focuses on the hands-on knowledge you need to achieve the best image quality, avoid artifacts, and interpret images accurately.
- Numerous high-quality images, many in full color, mirror the cardiovascular MR findings you see in practice.
- A companion DVD provides additional images and videos that further illustrate cardiovascular applications of MR imaging.
- A logical, consistent format in each chapter makes information easy to find.
Website Features
- Consult the book from any computer at home, in your office, or at any practice location.
- Instantly locate the answers to your clinical questions via a simple search query.
- Quickly find out more about any bibliographical citation by linking to its MEDLINE abstract.
- Images: Browse a Library of all book images. Easily select, organize, and download your images into a presentation.
Contents
Chapter 1 - Normal Cardiac Anatomy
Chapter 2 - Normal Vessel Anatomy
Chapter 3 - Left Ventricular Volumes, Ejection Fraction, Mass, and Shape
Chapter 4 - Measuring Regional Function
- Which quantities describe regional function?
- Velocity: how fast is the wall moving?
- Displacement: how far does the wall move?
- Strain: a measure of contractility?
- Other measurements
- Magnetic resonance tagging: noninvasive markers
- Displacement encoding with stimulated echoes
Chapter 5 - Size and Function of the Right Ventricle
Chapter 6 - Atria and Pulmonary Veins
Chapter 7 - Valvular Heart Disease
Chapter 8 - Myocardial Masses
- Normal cardiac structures that may be mistaken for a cardiac mass
- Benign primary cardiac masses
- Malignant primary cardiac masses
- Cardiac masses caused by systemic malignant processes
- Nontumor cardiac masses
Chapter 9 - Pericardial Disease
Chapter 10 - Dilated Cardiomyopathy and Myocardial Infarction
Chapter 11 - Hypertrophic Cardiomyopathy
- Early disease
- Apical involvement
- Patients at risk
- Obstruction
- Phenocopies
- Progressive disease
- Pitfalls
- Conclusion
Chapter 12 - Iron Cardiomyopathy
- Disease responsible for iron overload
- Organs affected by iron overload
- Iron adsorption and transport
- Iron stores and fluxes
- Iron entry and toxicity in the heart
- Clinical features of iron cardiomyopathy
- Use of cardiac magnetic resonance to detect iron cardiomyopathy
- Use of cardiac magnetic resonance to measure liver iron
- Relationship between total body iron stores and cardiac iron
- Slow elimination of cardiac iron
- Temporal relationships between cardiac and liver iron
- Cardiac iron risk in non-thalassemic iron overload
- When should cardiac iron screening be initiated?
- Summary of iron chelation therapy
- Comorbid deficiencies in iron cardiomyopathy
- Role of standard cardiomyopathy therapies
Chapter 13 - Myocarditis
Chapter 14 - Simple Congenital Heart Disease
- Interatrial communcations
- Ventricular septal defects
- Patent ductus arteriosus
- Partially anomalous pulmonary venous connection
- Evaluation of pulmonary-to-systemic flow ratio by cardiovascular magnetic resonance
- Coarctation of the aorta
Chapter 15 - Complex Congenital Heart Disease
Chapter 16 - Postoperative Evaluation of Congenital Heart Disease
Chapter 17 - Perfusion Stress Magnetic Resonance
- Side effects
- Visual assessment
- Semiquantification
- Full quantification
Chapter 18 - Wall Motion Stress Magnetic Resonance
Chapter 19 - Delayed-Enhancement Magnetic Resonance
Chapter 20 - Peripheral Magnetic Resonance Angiography
Chapter 21 - Diseases of the Aorta
- Normal anatomy of the aorta and branch vessels
- Aortic aneurysm
- Aortic dissection
- Aortic atherosclerosis
- Inflammatory disease of the aorta
- Coarctation of the aorta
- Aortic thrombus
- Postoperative appearance of the aorta
Chapter 22 - Renal Arteries
Chapter 23 - Coronary Arteries and Bypass Grafts
Chapter 24 - Coronary Anomalies
- Anomalies of origin and course: high risk
- Anomalies of origin and course: low risk
- Anomalies of termination
- Summary
Chapter 25 - Carotid Atherosclerotic Disease
Chapter 26 - Plaque and Wall Assessment
About the Authors
- Christopher M. Kramer, MD, Professor, Departments of Medicine and Radiology; Director, Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, Virginia.
- W. Gregory Hundley, MD, Professor, Departments of Internal Medicine (Section on Cardiology) and Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina.
Product Details
- Hardcover: 376 pages
- Publisher: Saunders; Har/Psc edition (2010)
- Language: English
- ISBN-10: 1416061355
- ISBN-13: 978-1416061359
- Product Dimensions: 11.1 x 8.7 x 0.8 inches
List Price: $195.00
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