Carotid plaque heterogeneity and lower calcified volume on computed tomography angiography are associated with...

The impact of carotid artery plaque calcification on computed tomography angiography (CTA) is unclear, despite subclassifications by size, distribution, and calcification scores. Symptomatic plaques appear to be more heterogeneous on ultrasound, but similar findings on CTA have not been published. We hypothesized that calcification and heterogeneity on CTA can discriminate symptomatic and asymptomatic plaques.

CTA was performed on 152 patients with internal carotid artery stenosis before endarterectomy. Plaque volumes were assessed using a novel multi-slice cylindric approximation and divided into non-calcified and calcified plaque. Comparative analysis of symptomatic and asymptomatic patients was performed for clinical differences, stenosis severity, and plaque components: calcified volume, subtypes of calcification and heterogeneity (measured as the coefficient of variance). Multiple logistic regression was performed to assess odds ratios for neurological symptoms. A receiver operating characteristic analysis was used to investigate the prediction of the symptomatic status via plaque components.

The odds ratios for %-calcified volume, superficial calcification, and a calcification score were OR 0.43 (0.22-0.84), 0.47 (0.22-1.0), and 0.78 (0.28-1.38), respectively. An increase of non-calcified plaque heterogeneity by 0.1 in the coefficient of variance was associated with a 41 % higher probability of being symptomatic (OR 1.41 (1.13-1.75)). There were no relevant differences in degree of stenosis and cardiovascular risk factors between symptomatic and asymptomatic patients.

Assessing plaque heterogeneity and calcification volume on CTA using a novel, simple volumetric approximation might be a useful indicator of higher plaque vulnerability in patients diagnosed with carotid artery stenosis, potentially improving diagnostic risk stratification.