Admission hyperdense sinus sign predicts poorer outcomes in cerebral venous sinus thrombosis

Background: The hyperdense sinus sign (HDSS) is a readily identifiable non-contrast CT marker of acute thrombus in cerebral venous sinus thrombosis (CVST). We aimed to characterize HDSS associated features and prognostic significance. Methods: Data from prospective multicenter CVST registries was analysed. HDSS was defined as attenuation > 70 Hounsfield units within a thrombosed venous structure. Baseline characteristics and outcomes were compared between patients with and without HDSS on admission CT. Multivariable logistic regression identified independent predictors of Excellent-Functional-Outcome (mRS 0–1) and remote seizures. Results: Among 465 patients (mean age 41.9 ± 18.4 years; 64.3% female), 178 (38.3%) exhibited HDSS. Patients with HDSS had higher rates of oral contraceptives use (28% vs 18%, p = 0.009), seizures at presentation (23% vs 14%, p = 0.015), superior sagittal (45% vs 35%, p = 0.028) and transverse sinus involvement (78% vs 67%, p = 0.01), deep venous thrombosis (8% vs 2%, p = 0.003), cortical vein thrombosis (19% vs 9%, p = 0.004), and multisite occlusion (34% vs 22%, p = 0.002). Parenchymal lesions were more common in HDSS patients, including intracerebral hemorrhage (27% vs 13%, p < 0.001) and venous infarction (22% vs 11%, p = 0.004). On day-90, HDSS was associated with lower Excellent-Functional-Outcome rates (71% vs 82%, p = 0.022), higher rates of remote seizures (9% vs 3%, p = 0.001), and similar recanalization rates. HDSS independently predicted reduced odds of Excellent-Functional-Outcome (OR = 0.491 [0.261–0.926], p = 0.028) and increased remote seizures (OR = 2.693 [1.057–6.861], p = 0.038). Conclusions: HDSS identifies a CVST subgroup with more extensive thrombosis, greater parenchymal injury, and poorer outcomes, supporting its utility in early risk stratification.