Background: Carotid web (CW) is an under-recognized cause of ischemic stroke. The hyperdense middle cerebral artery sign (HMCAS) on non-contrast head CT (HCT) is indicative of a red blood cell (RBC)-rich thrombus, as opposed to the platelet/fibrin-rich clots typically seen in atherosclerosis. This study evaluated the association between CW and the HMCAS when comparing to Methods: We conducted a retrospective analysis of patients with MCA (M1) occlusion and ipsilateral CW from an ongoing registry at a Comprehensive Stroke Center. Nearest-neighbor matching was used to select comparison groups with extracranial high grade(70-99%) large artery atherosclerosis (LAA) and cardioembolism. HCT scans prior to thrombectomy were reviewed by a vascular neurologist for detection of HMCAS, with one-third also reviewed by a neuroradiologist. Inter-rater agreement was assessed using Cohen’s kappa. Hounsfield units (HU) were measured at the thrombus site; in cases without HMCAS, CTA was co-registered for localization. The primary outcome was to measure the association between HMCAS and ipsilateral CW when compared to LAA; the secondary outcome was excellent recanalization (TICI ≥2c). After adjusting for gender and smoking, multivariate logistic regression was used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Results: Seventy-six patients were included: 22 with CW, and 27 each with cardioembolism and LAA. Mean age was 57±10 years; 60.5% were male. Median HU was higher in CW-related LVO (55.6 IQR 47–59) compared to LAA (44 IQR 36–53, p = 0.05). Inter-rater agreement was substantial (90% agreement; κ = 0.77). CW was independently associated with HMCAS (aOR 5.63; 95% CI 1.50–21.12; p = 0.01) compared to LAA. Compared to cardioembolism, carotid webs showed a non-significant trend toward association with HMCAS (aOR 3.03; 95% CI 0.79–11.58; p = 0.105). Both CW (aOR 4.93;95% CI 1.06-22.87, p=0.042) and cardioembolism ( aOR 6.13; 95% CI1.33-28.22, p=0.020) were significantly associated with excellent recanalization (≥TICI2c) when compared to LAA. Sensitivity analyses using relative HU thresholds showed CW was associated with HMCAS at rHU ≥1.3 (aOR 4.36; 95% CI 1.22–15.55; p = 0.023) and cardioembolism at rHU ≥1.2 (aOR 4.23; 95% CI 1.15–15.47; p = 0.03). Conclusion: CW is associated with a higher likelihood HMCAS and excellent recanalization, suggesting an RBC-rich thrombus phenotype. These findings have implications for stroke mechanism classification
Khan et al. (Thu,) studied this question.