16-row CT reduces need for coronary angiography

Radiologists are still exploring the full potential of CT in the coronary arteries. Dutch researchers suggest it may be able to replace conventional angiography in some patients by dictating appropriate treatment without additional invasive imaging.

Researchers used 16-row CT to evaluate stenosis in 22 patients who then received conventional angiography. They then compared the recommendations made based on CT with those made by cardiologists following angiography. Fifty nine percent of patients were recommended for percutaneous intervention, and another 14% referred for coronary artery bypass graft. For 27%, no intervention was recommended.

The MDCT readers gave the correct treatment recommendation for 18 of 22 patients. In all four other patients, they recommended more aggressive therapy than the angiography readers - three were upgraded to percutaneous intervention instead of none, and one was recommended for CABG instead of percutaneous intervention.

"Overall, CT was 93.8% sensitive and 95.6% specific," said lead researcher Dr. Joost Dorgelo of Groningen. "In 82% of cases, MDCT recommended the correct course of treatment."

Researchers still need to determine the best patient population to undergo MDCT evaluation instead of angiography, Dorgelo said Friday afternoon at the European Congress of Radiology.

Other researchers are experimenting to find out how well MDCT compares with other methods of quantifying and characterizing plaque. Early studies suggest eight- and 16-row CT can evaluate the main branches of the arteries feeding the heart, and differentiate calcified, soft, and mixed plaques. It's still unclear, however, exactly how those evaluations translate to overall patient risk for disease, and there is no gold standard for quantifying plaque burden.

Researchers from Massachusetts General Hospital, meanwhile, looked at plaque burden based on age and gender. They found that while men's plaques are slightly larger, neither age or sex is a statistically significant factor in measuring plaque. The good news for future research is that populations can be studied without stratifying for those characteristics.