SAN FRANCISCO — Cardiac MRI with late gadolinium enhancement is the imaging technique of choice when the goal is tissue characterization and infarct detection in heart failure, Dr. Christopher M. Kramer said at a cardiovascular imaging conference sponsored by the American College of Cardiology.
Cardiac magnetic resonance (CMR) provides outstanding image quality, excellent quantification, and tissue characterization, said Dr. Kramer of the University of Virginia, in Charlottesville. In addition, Gadolinium contrast is easy to use and safe with CMR and also offers the ability to assess intramural function.
However, CMR devices are not portable, are quite expensive, and are not readily available. Physicians need to have extensive training in the use of CMR and the technique is not suitable for patients with implanted metallic devices such as pacemakers and implantable cardioverter defibrillators. Furthermore, assessment of diastolic function is not routine with CMR.
Echocardiography also has a number of advantages. The devices are portable and relatively inexpensive, and they are readily available. Generations of cardiologists have established its validity and all cardiologists become proficient in the use of echo during their training. Contrast can be added to echocardiography, and the assessment of diastolic function has become routine.
But the technique is subject to variable image quality and poor windows. The results tend to be qualitative, and quantitation can be difficult. Newer 3-D echocardiographic techniques address some of these issues, but such devices are not widely available.
Gadolinium-enhanced CMR is useful in determining if cardiomyopathy is ischemic or nonischemic. Studies have also shown the value of enhanced CMR as a marker in late-stage myocarditis, hypertrophic cardiomyopathy, amyloidosis, sarcoidosis, and Chagas disease.
Dr. Kramer noted that echocardiography is useful in several circumstances, especially for diastolic function and when “quick and easy” is adequate, but CMR is best for regional systolic function, for differential diagnosis and tissue characterization, and when quantitation is needed and 3-D echo is unavailable.