Computed tomography (CT) scans of the heart are helpful in identifying heart disease patients who need treatment, but they sometimes fail to detect blockages and incorrectly identify blockages where none exist, according to a new study published in the November 27, 2008 issue of the New England Journal of Medicine.

Physicians from Johns Hopkins University School of Medicine and their colleagues evaluated the coronary arteries, or heart blood vessels, of 291 patients using both CT angiography and conventional angiography, a more invasive procedure. Of these patients, 56% were found to have obstructive blockages in their coronary arteries. The physicians found that CT angiography was accurate in identifying the presence and severity of obstructive coronary artery disease, however it sometimes missed existing blockages and indicated blockages that did not actually exist.

The authors of the study suggest that, based on their findings, CT technology is not yet ready to replace conventional angiography as the standard of care for identification of coronary artery blockages.