Ultra-high-resolution and dual-energy computed tomography of carotid artery plaques differentiate symptomatic and asymptomatic patients by novel volumetric analysis.

OBJECTIVES

The indication for carotid endarterectomy (CEA) mainly relies on the degree of stenosis and neurological symptoms. Plaque vulnerability has been associated with stroke risk, but identification on single-energy computed tomography (CT) has yielded heterogeneous results and is not routinely applied to clinical diagnostics. Hence, we intended to analyse CEA specimens for vulnerability features using dual-source CT and correlate these features with the presence of preprocedural symptoms.

METHODS

CT was performed on 187 carotid plaque specimens using ultra-high-resolution and dual-energy imaging on a dual-source scanner. Plaques were separated into calcified versus non-calcified volumes and analysed concerning HU-density, calcifications and volumetric dual-energy indices (DEIs). Comparative statistical analysis of plaque characteristics was performed with respect to the presence of neurological symptoms.

RESULTS

The degree of stenosis of symptomatic and asymptomatic plaques was indifferent (69.2 ± 12.3% vs 66.3 ± 13.7%). The highest diagnostic accuracies were obtained by the % calcified volume (AUC 0.63 (0.54-0.71)), average whole plaque HU (AUC 0.71 (0.64-0.79)), profound calcification (AUC 0.74 (0.66-0.81)), calcification spots <1 mm (AUC 0.71 (0.63-0.79)) and spotty calcification (AUC 0.74 (0.66-0.82)). The diagnostic accuracy for symptomatic plaques was insignificant using average non-calcified plaque HU (AUC 0.59 (0.48-0.65)), but significant using average non-calcified plaque DEI (AUC 0.66 (0.58-0.74)).

CONCLUSIONS

Symptomatic plaques were identified best by measuring density of the whole, calcified or non-calcified plaque and via spotty, profoundly localized and less dense calcification. A volumetric DEI identifies symptomatic plaques with non-calcified plaque characteristics more accurately than single-energy CT. Future clinical studies are necessary to confirm these findings in patients.