Use of Contrast-enhanced Carotid Ultrasonography in Preoperative Assessment for Carotid Artery Stenting

Objective: Contrast-enhanced carotid ultrasonography (CEUS) is a new technique for assessing carotid artery plaques. The present study attempted to demonstrate the association between the findings of CEUS performed prior to carotid artery stenting (CAS) and plaque debris caught during CAS. Methods: This study was conducted with 16 patients (15 men, 1 woman; mean age: 74.8 years) who had undergone evaluation of carotid plaque vulnerability followed by CAS. The carotid plaque evaluation consisted of CEUS and MRI. The amount of debris retrieved during CAS was semi-quantitatively classified into three grades (large, moderate, and small) by three independent physicians based on inspection of photographs of retrieved debris. The existence of a correlation between CEUS findings and the amount of debris was examined. Results: Enhanced plaque on CEUS was observed in 7 of 16 patients. A large amount of debris was observed during CAS in four of the seven patients with CEUS-enhanced plaques that were also assessed as unstable on MRI, while two patients had a moderate amount and one patient had a small amount of debris. There were significant correlations between the amount of debris and plaque enhancement on CEUS, unstable plaque on MRI, and enhancement of plaque on CEUS with unstable plaque on MRI (p = 0.036, p = 0.029, p = 0.036, respectively). For the prediction of moderate to large amount of debris occurring in CAS, enhancement of plaque demonstrated by CEUS had a sensitivity of 66.7% and a specificity of 85.7%, unstable plaque determined by MRI had a sensitivity of 100% and a specificity of 42.9%, and enhancement of plaque by CEUS and unstable plaque determined by MRI had a sensitivity of 100% and a specificity of 75%. Conclusion: Plaque vulnerability assessment using the combination of CEUS and MRI can predict the amount of debris retrieved during CAS, while using CEUS alone proved to be insufficient.