CT used to measure atherosclerotic plaques subsequent to ACS
The CT characteristics of the lesions responsible for subsequent acute coronary syndrome (ACS) include larger plaque volume as well as larger soft plaque area and volume, according to a poster presentation at the American Heart Association conference held this week in Orlando, Fla.

Sadako Motoyama and colleagues from the Fujita Health University in Toyoake, Japan, and the Universitiy of California Irvine in Irvine, Calif., conducted the study.

The imaging characteristics of vulnerable plaques have almost always been described by evaluating the lesions that have already resulted in ACS, said researchers. In contrast, Motoyama and colleagues identified the CT characteristics of atherosclerotic lesions which were associated with subsequent development of ACS. In a previously conducted study, researchers found that CT characteristics of culprit lesions in ACS included positive remodeling (PR) and soft plaques (SP) with low attenuation of less than 30HU.

In the study, 1,154 patients underwent CT angiography with a follow-up range of 12 to 51 months. The presence of PR and SP were evaluated in all patients. Plaques in patients with either PR or SP were characterized for plaque volume and consistency using Sure Plaque software from Toshiba Medical Systems. Lesions with previous percutaneous coronary intervention (PCI) and target lesions for elective PCI were excluded. The plaque characteristics of lesions resulting in ACS were compared with those not resulting in ACS.

According to their results, 10 of 1,154 patients suffered from ACS after CT. Of these 10 patients, seven had PR and six had SP, while eight patients had either PR or SP. The two patients with no PR or SP demonstrated large calcification. PR or SP was detected in 54 patients without subsequent development of ACS.

Total plaque volume, soft plaque volume and maximum soft plaque area in cross-sectional images were significantly larger in the group who suffered ACS than in the group that did not.