OCT may be best tool to detect vulnerable coronary plaque
WASHINGTON—Optical coherence tomography (OCT), a newly evolving imaging method, may be the best tool available to detect vulnerable plaque in coronary arteries, according to findings presented Monday at the 20th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium.

A team of researchers at Ajou University School of Medicine in Suwon, Korea, are reporting that OCT provides superior contrast and resolution in imaging the components of plaque in coronary arteries versus other methods including intravascular ultrasound (IVUS) and virtual histology (VH-IVUS). The findings are summarized in the abstract, “Comparison of Intravascular Modalities for Detecting Vulnerable Plaque: Conventional Ultrasound vs. Virtual Histology vs. Optical Coherence Tomography.”

“OCT may answer longstanding questions about the relationship between vulnerable plaque and the risk of heart attack,” according to lead investigator So-Yeon Choi, MD, PhD.

To assess the ability of each imaging modality to detect the specific characteristics of vulnerable plaque, investigators performed IVUS, VH-IVUS and OCT in 48 patients, who were categorized as having stable angina pectoris (15) or acute coronary syndromes (33).

The researchers found that “OCT easily detected vulnerable plaque,” with two observers analyzing the images independently.

 “OCT detected most of the major and minor characteristics of vulnerable plaque, including the thin cap with large lipid core, and it has the ability to detect thrombus and fissured plaque at a level that is four to five times better than that of other modalities,” Choi said. “Because of OCT’s high-resolution capabilities, which is almost 10 times greater than with IVUS and related modalities, it can assess this tissue more accurately than other imaging methods.”

As a result, the investigators concluded that OCT may provide a better understanding of the natural progression of coronary artery disease. For example, stenosis or erosion of endothelial cells with plaque could be detected even in patients with stable angina.

"That finding is something that we had never experienced before; we should study more the clinical implication of these findings," Choi said. "New evolving OCT imaging is moving closer to becoming a powerful diagnostic tool that will provide new insights into the etiology and treatment of coronary artery disease."

The researchers noted that current OCT technology does have some limitations, though. It needs a blood-clear zone and a low penetrating depth to be most effective. However, they noted that procedure is safe and can be performed in a cath lab.