Abstract TP223: Carotid Web Quantification: Comparative Analysis Between 1-D, 2-D and 3-D Methods

Abstract

Introduction: Carotid webs (CaW) are now recognized as a cause of ischemic stroke specially in young patients. The thromboembolic potential appears related to the CaW morphology. We aim to evaluate the reliability of different measurements methods for the quantification of CaW size. Methods: This was a retrospective analysis of our CaW database (spanning September 2014 - July 2019). CT angiograms (CTA) were reviewed independently by two raters, blinded to the clinical information and laterality of the stroke/TIA. CaW were quantified with 1-D, 2-D and 3-D measurements (Figure) via Osirix software: 1-D was obtained with an oblique MIP with a perpendicular view of the CaW allowing the measurement of the base and the length of the CaW projection into the lumen; 2-D was defined by the area of the CaW delineated free-hand in the same view as the 1-D; 3-D was calculated with thin axial CTA cuts via volumetric analysis of free-hand delineated CaW limits. Intraclass correlation coefficient was used to evaluate the inter-rater agreement and two sample t-test/ Mann Whitney U test to compare imaging characteristics between symptomatic and asymptomatic CaW. Patients with superimposed CaW thrombus and no repeat imaging were excluded. Results: Thirty-six patients with 46 CaW were included (33 symptomatic and 12 asymptomatic). Median age (IQR) was 49.5 (40.5-58.5) years, 77.8% were female and 77.1% were black. Inter-rater agreement was 0.961 (p<0.001) for 1-D, 0.933 (p<0.001) for 2-D and 0.936 (p<0.001) for 3-D measurements. Mean web length (1-D) was 3.1mm vs 2.5mm (p=0.01), while median area (2-D) was 5.8 vs 5.3mm 2 (p=0.35) and median volume (3-D) was 15.0 vs 10.8mm 3 (p=0.03) amongst symptomatic vs asymptomatic CaW, respectively. Conclusion: CaW size quantification (1-D, 2-D and 3-D) is highly reproducible. One dimensional measurement may be the method more strongly related to symptomatic vs asymptomatic status.