Society expands influence, homes in on morphology and function

The 2005 Society for Cardiovascular Magnetic Resonance meeting reflected the opportunities and challenges unique to this diagnostic imaging discipline. Cardiac MR's growing professional acceptance helped spur a third consecutive attendance record this year, and the number of scientific papers and posters submitted for presentation rose as well.

As was the case in 2004, delayed enhancement CMR took center stage. Last year, the program emphasized DE-CMR's value for characterizing myocardial scarring associated with ventricular arrhythmias. CMR's capabilities in this regard have created opportunities to percutaneously ablate these lesions under MR guidance, reducing the risk of sudden death.

The emphasis in 2005 shifted to demonstrating that the prognostic power of DE-CMR extends beyond its well-established ability to predict whether a heart attack patient will benefit from revascularization. Assessment of the extent of myocardial infarction, characterized with CMR wall motion and DE-CMR measures, may be as powerful as ejection fraction in identifying the best candidates for an implantable cardioverter defibrillator. One study suggested that DE-CMR results could be added to Framingham test scores to improve the assessments of future cardiac risk among symptomatic women.

Although the SCMR meeting was almost entirely dedicated to exploring cardiac MR development, the rapid advancement of multislice CT for cardiac workups could not be ignored. Incremental improvement in the quality of coronary artery MR was again demonstrated in the technical sessions, but cardiologists and radiologists at the conference showed growing awareness that MSCT is moving ahead of MR for coronary artery imaging.

SCMR officials admit that better ways to diagnose coronary artery disease and infarction will arise from several imaging modalities. MRI may be best suited for cardiac morphology, function, and myocardial perfusion, and CT may succeed in cardiac catheterization for diagnosing CAD. The officials also acknowledge FDG-PET as the gold standard in assessing myocardial viability.

Still, the ability of CMR to produce exquisite cardiac images without exposing patients to ionizing radiation remains appealing. MSCT coronary studies expose patients to twice as much ionizing radiation as fluoro-guided cardiac catheterization, according to Dr. Christopher Kramer, SCMR scientific program chair. The implications of radiation exposure are daunting, especially for young patients who frequently need many imaging studies to guide the course of their cardiac treatment.

INTERVENTION ADVANCES

Advances in CMR applications in guiding interventions to correct congenital cardiac abnormalities were noteworthy. Researchers added to the growing body of work that aims to create ways to perform real-time MR-guided percutaneous interventions. Especially impressive were reports from the cardiac energetics laboratory of the National Institutes of Health's Heart, Lung, and Blood Institute. A safe, practical balloon catheter and guidewire guidance systems were demonstrated in swine models. After many years of careful development, the first experimental applications in humans are not far away.

The implications of MSCT arose again in sessions devoted to CMR in community practice. Attendees were asked whether the scope of the society should be expanded to encompass CT. The answer articulated by Dr. Gerald Pohost, director of cardiovascular imaging at the University of California, Los Angeles, was a resounding no.

During a lively practice issues session, Pohost was sympathetic, however, to calls to liberalize the SCMR training guidelines that define clinical CMR competence. Radiologists and cardiologists in the audience were especially interested in reducing the current three months of dedicated CMR training and 150 supervised CMR exams the society requires to establish level II competence-the minimum requirement for unsupervised reading of CMR studies-and to qualify to bill Medicare for the procedures.

Although looser guidelines would encourage CMR expansion, they run counter to the American College of Radiology's efforts to tighten imaging standards and would add fuel to its claim that patient safety could be compromised if poorly trained cardiologists are allowed to perform imaging procedures. The session also considered the potential threat that intersocietal feuding poses to joint ACR-American College of Cardiology efforts to update CMR billing codes and to gain reimbursement for new CMR procedures.

Such discussions are indicative of CMR's growing maturity and the importance of the SCMR meeting's role in encouraging debate among its practitioners. This year's meeting demonstrated that CMR is no longer just another promising imaging modality. In technical, professional, and political terms, it has arrived.