Non-invasive CT scans proved to be as good as conventional angiography at spotting blocked arteries in a study by researchers at Johns Hopkins University in Baltimore, which was published in this week’s edition of New England Journal of Medicine.

Led by Dr. Julie Miller, an interventional cardiologist at Johns Hopkins University of Medicine, the researchers found that so-called 64-row computed tomography, or CT scans were 93 percent as precise as conventional cardiac catheterization without subjecting a patient to an invasive procedure. The procedure does not take more than 10 minutes, which is much faster than the classic procedure, which takes about an hour.

“Having the scan is a noninvasive procedure, and that is very attractive. Patients do not undergo the risk, even though it is small, of angiography,” Dr. Miller said.

The only side effect of such a procedure is that patients are exposed to a high quantity of radiation, thus raising the risk of cancer.

The researchers used a 64-slice CT scanner made by Toshiba Medical Systems, which funded the study along with the National Institutes of Health and private foundations.

But, radiation is not the only concern, says Dr. Rita Redberg, a professor at the University of California at San Francisco School of Medicine, who wrote an article accompanying the study. The devices are quite expensive.

“It's not always true that more tests are better, and it does drive up our health-care costs without a clear benefit to patients,” she explains.