Myocardium becomes key to CMR's success

By: James Brice, Senior Editor

To gain acceptance, every investigational imaging technology needs an indispensable application. CT's star rose after Godfrey Hounsfield's invention began producing astonishing brain images. Sonography became the modality of choice for fetal imaging after obstetricians recognized its ability to image in real-time without ionizing radiation. In comparison, clinical cardiac MRI has progressed slowly because it has never been considered the preferred modality for any high-volume procedure.

But this may soon change, according to the organizers of the 2003 meeting of the Society for Cardiovascular Magnetic Resonance. The February conference coincided with the publication of a major study of late-enhancement contrast-enhanced MRI. According to trial results published in The Lancet (2003;361:374-379), the technique identifies small subendocardial infarctions missed by stress/rest SPECT.

SCMR sources say that the article's take-home message is that late-enhancement contrast-enhanced MRI is actually better than thallium SPECT for predicting whether heart attack patients will benefit from revascularization. The findings have caused quite a buzz.

"This is the kind of information you can build a business plan around," said Robert Balaban, Ph.D., chief of the energetics laboratory at the National Heart, Lung, and Blood Institute.

Other sources claim that if this CMR application makes into the mainstream, additional high-volume applications will follow.

Such reasoning is easy to accept, given the high quality of presentations and posters at the conference. Anyone who has not seen state-of-the-art CMR lately would be impressed by the improved resolution. Although it is not clear whether CMR is easier to perform, its high spatial resolution results in studies of cardiac anatomy that are increasingly easier to interpret. Studies of first-pass perfusion MRI added more evidence documenting its ability to diagnose coronary artery disease, and progress was shown in real-time MRI for interventional guidance and coronary wall imaging for investigating atherosclerotic inflammation and plaque.

The innovations on display at the SCMR meeting demonstrate that cardiac MRI is already clinically relevant, and it might be poised to become indispensable.