Dual-energy CT aids in detailing stenosis with CTA

Combining dual-energy CT with coronary CT angiography (CTA) enhances accuracy when identifying coronary stenosis, according to a new study in the American Journal of Roentgenology.

Published this month, the study was led by Sung Min Ko, MD, with the Konkuk University School of Medicine in South Korea.

According to the researchers, CTA allows for noninvasive study of high-grade coronary stenosis with high accuracy but is prone to false positives. Additionally, the authors write, a finding of stenosis through CTA does not determine the significance of a lesion.

Thanks to new technology available to radiologists, dual-energy CT (DECT) can create iodine maps which are used to analyze iodine distribution inside the myocardium.

“We evaluated the performance of stress perfusion DECT and its incremental value when used with coronary CTA for the detection and exclusion of hemodynamically significant coronary stenoses causing complete reversible perfusion defects compared with the combination of invasive coronary angiography (ICA) and cardiovascular stress perfusion MRI as the reference standard,” wrote Ko and colleagues.

One hundred patients with suspected or confirmed coronary artery disease without chronic myocardial infarction detected with coronary CTA were evaluated between May 2010 and May 2012 with stress perfusion DECT, stress perfusion MRI and invasive coronary angiography.

The study showed the DECT stress perfusion exams compared with cardiovascular stress perfusion MRI resulted in 89 percent sensitivity in the detection of perfusion defects, specificity was 74 percent, positive predictive value was 73 percent and negative predictive value was 90 percent.

Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95 percent, 61 percent, 61 percent and 95 percent, respectively. The values for stress perfusion DECT were 92 percent, 72 percent, 68 percent and 94 percent, respectively. The values for coronary CTA and stress perfusion DECT were 88 percent, 79 percent, 73 percent and 91 percent, respectively.

The results showed that compared with the combined ICA and MRI, stress perfusion DECT proved accurate and provided diagnostic value over coronary CTA alone when detecting significant coronary stenosis inducing complete reversible myocardial perfusion defects.

“Our results help to validate the clinical usefulness of perfusion CT,” the authors wrote. “Theoretically, the combined use of DECT and perfusion CT (stress perfusion DECT) has the potential to be superior to conventional perfusion CT for the detection of perfusion defects.”

Ko and colleagues concluded that stress perfusion DECT has the potential to complement the accuracy of coronary CTA for identifying hemodynamically significant stenosis.