Next-gen scans cut radiation dose by 61% in CT angiography patients

Using advanced scanner technology reduced the radiation dose by 61 percent in patients undergoing cardiovascular CT angiography at no loss in image quality, according to a study published in the May/June issue of the Journal of Cardiovascular Computed Tomography.

Kavitha M. Chinnaiyan, MD, of William Beaumont Hospital in Royal Oak, Mich., and colleagues went beyond small studies that showed high-pitch spiral CT scans can lower radiation dose in patients being evaluated for coronary artery disease, pulmonary embolism and aortic disease. Their large study included nine centers that retrospectively collected data on patients scanned with first-generation scanners and then prospectively acquired data on patients scanned with second-generation scanners.

Their primary endpoint was total radiation dose, estimated as dose-length product (DLP). Secondary endpoints focused on image quality.

Patients were enrolled between 2011 and 2012. The control group (1,097 patients) were scanned with either a Siemens Sensation 64 or a Siemens Definition dual-source system. The study group (988 patients) were scanned by advanced scanners with latest generation detectors.

The median DLP was drastically lower in the study group compared with the control, at 260 vs. 668 mGy∙cm. They calculated a significant reduction in a subgroup analysis as well: 260 vs. 606 mGy∙cm for coronary artery disease patients; 245 vs. 633 mGy∙cm for pulmonary embolism patients; 268 vs. 821 mGy∙cm for aortic disease patients; and 491 vs. 954 mGy∙cm for triple rule-out. They saw a significant reduction in contrast volume in all subgroups as well.

“The study objective was to establish the change in dose within the same sites during general clinical practice; therefore, the study did not enforce a predefined ‘best practice’ scan technique,” they wrote. “Therefore, this study suggests it is likely that if advanced scanners are made available, standard clinical practice will result in substantial reduction in diagnostic radiation exposure.”

They noted a slight increase in image noise as well as a decrease in image motion; consequently, image quality remained the same in both groups.