Abstract TP136: Four-dimensionally Guided Three-dimensional Color-doppler Ultrasonography Quantifies Carotid Artery Stenoses With Equally High Reproducibility and Accuracy Compared to Catheter Angiography

Introduction: Clinical stratification in patients with ICAS largely depends on symptomatic status and stenosis grading. The purpose was to analyze the agreement and binary accuracy for the degree of internal carotid artery stenoses (ICAS) as determined by four-dimensional (4D) real-time guided three-dimensional color-Doppler (3DC) ultrasonography (4D/3DC-US) compared to catheter angiography (CA). Hypothesis: We hypothesized that 4D/3DC-US is non inferior to CA in grading ICAS in selected patients. Methods: Screening with 4D/3DC-US was performed in 93 patients (122 ICAS) admitted to our vascular center.Main exclusion criteria were insufficient image quality, previous revascularization and contraindications to CA. Eighty patients were prospectively examined in optimal planes with 4D-US assisted static 3DC-US color-Doppler (10MHz) followed by blinded multiplanar off-line rendering to determine %-NASCET stenosis. Multiplane selective CA of the same ICAS were quantified with dedicated software in a blinded fashion. Results: Quantitative CA of 103 stenoses with a mean degree of 65 ± 17% were compared to 4D/3DC-US resulting in a Pearson correlation coefficient of 0.89 and a standard deviation of differences (SDD) of 8.1% at a bias of +1.7%. Binary 50, 60 and 70%-stenosis detection with 3DC-US revealed an accuracy of 96, 89, 85%, a sensitivity of 97, 92, 87% and a specificity of 92, 83 and 84%. Interobserver SDD for CA of 52 stenoses (7.2%) did not differ from SDD between 3DC-US and CA (P = 0.274). Conclusions: 4D/3DC-US allowed good metric stenosis quantification and accurate binary classification with high reproducibility in a selected cohort.