Relationship between carotid web morphology on CT angiography and stroke: A pooled multicenter analysis.

Background: The Carotid web (CaW) is a cause of stroke, particularly in younger individuals. However, the frequency and the radiological features of the web's morphology associated with stroke risk are uncertain. We determined the CaW radiological features on computed tomography (CT) angiography associated with ipsilateral stroke.

Materials and methods: Data from six studies of patients with acute ischemic stroke were pooled. Identification and measurement of CaWs were performed by experienced readers using baseline neck CT angiography. We assessed six 2D CaW radiological features on sagittal oblique images, namely, main axis length, thickness, height, base width, distance to wall, and angle between the web main axis and carotid wall, and CaW volume on 3D images. CaWs were divided into symptomatic if acute ischemic stroke was in the ipsilateral internal carotid artery territory and its etiology was undetermined and asymptomatic if one condition was unmet. Univariable and multivariable analyses were conducted to assess the association between each radiological CaW feature and symptomatic CaW.

Results: Of the 3442 patients in the pooled data with assessable CTAs, 60 (1.7%) had CaW. In patients with CaW, median age was 59 (interquartile range [IQR]: 50-68) years, 60% were women, and 3 patients had bilateral CaWs. There were 39 (62%) symptomatic and 24 (38%) asymptomatic CaWs. Patients with symptomatic CaW were younger (55 (IQR: 49-61) years versus 69 (IQR: 52-75) years), had lower rates of hypertension (9 (25.0%) versus 12 (57.1%)) and more intracranial large vessel occlusions compared to patients with asymptomatic CaWs. After adjusting for age, hypertension, and occlusion location, CaW length (adjusted odds ratio (aOR) 1.84 (95% confidence interval [CI]: 1.03-3.28)), thickness (aOR: 2.31 (95% CI 1.08-4.97)), volume (aOR: 1.07 per 1 mm³ increment (95% CI: 1.01-1.12)), and angle relative to the carotid wall (aOR: 0.95 (95% CI: 0.91-0.99)) were associated with symptomatic CaW.

Conclusion: Radiological assessment of CaW morphology may determine its potential causal role in ischemic stroke etiology. Symptomatic CaWs tend to be longer, larger, and oriented at more acute angles relative to the carotid wall as compared to asymptomatic CaWs.