(Courtesy RSNA)

CT can detect arterial plaque for diabetics

April 22, 2014
by Kristen Fischer, DOTmed News
Diabetics, who face a high risk for cardiovascular events such as heart attacks, can leverage computed tomography (CT) angiography to evaluate arterial plaque, according to a new study in the journal Radiology.

Quantitative plaque analysis with coronary computed tomography angiography (CCTA) can depict a map of the arteries with a low dose of radiation. It can then show how much plaque is in a patient's arteries. The technology can also differentiate between calcified (stable) plaque and non-calcified (soft) plaque.

Coronary artery calcium (CAC) scoring with CT, another way to measure artery plaque, has its limitations, so CCTA is a welcome development. Intravascular ultrasound can be used to differentiate between the types of plaque, but that procedure is invasive.

"Calcium scoring measures how much calcified plaque a person has, but it doesn't measure the component that's not calcified, and that's the component that tends to be dangerous," said Dr. João A. C. Lima, a physician in the Johns Hopkins University cardiology department. "These findings represent a very important step in the ability to quantify plaque, particularly non-calcified plaque."

Researchers from the university, the National Institutes of Health (NIH) and the Intermountain Medical Center Heart Institute in Salt Lake City looked at the efficacy of CCTA in 224 asymptomatic diabetic patients. They measured coronary artery wall volume and length to come up with a coronary plaque volume index (PVI) for each patient.

They found that younger people with a shorter duration of diabetes had a greater percentage of soft plaque. The researchers said they would need a clinical trial to find out if a lower risk factor would reduce PVI.

Only about one-third of the coronary plaque in patients showed calcification, which emphasizes the presence of soft plaque. People with soft plaque are more likely to respond better to statin medications, for example, Lima said.

"Coronary plaque volume index by CCTA is not only clinically feasible and reproducible in patients with diabetes," said Dr. David A. Bluemke from the NIH Clinical Center. "It provides a more complete picture of the coronary arteries that could be routinely applied in at-risk patients."

"Now that we have baseline indices of plaque in the study patients, we can look for people who, despite optimal management, experience a cardiovascular disease event like a heart attack," Bluemke added.

Diabetics aren't the only ones who may be able to benefit from CCTA, other high-risk patients would likely see advantages to having the scan done. It also may aid doctors in predicting and treating plaque development before PVI can rise.