OBJECTIVE: To evaluate early and mid-term imaging and clinical outcomes following transvenous embolization of cerebrospinal fluid-venous fistulas (CSFVFs) in patients with spontaneous intracranial hypotension (SIH). METHODS: From November 2022 to November 2024, 60 consecutive patients with SIH and confirmed CSFVF underwent transvenous embolization using Onyx. Of these, 40 patients underwent brain MRI pre-treatment, 24 hours post-treatment, and at a 3-month follow-up. The primary outcome was regression of brain MRI abnormalities at 24 hours and 3 months. Secondary outcomes included rates of symptom improvement, predictors of clinical improvement, and complication rates. RESULTS: The mean patient age was 61 years, and 65% were female. All procedures were technically successful. The median SIH score significantly decreased from 6 pre-treatment to 3.5 at 24 hours (P=0.01) and to 2 at 3 months (P=0.004). Early improvement in SIH score correlated with clinical improvement at 24 hours (P=0.002), which was observed in 77.5% of patients. Pachymeningeal enhancement (87.5%) and venous sinus engorgement (75%) were the most common MRI abnormalities. Both findings regressed in approximately 50% of patients at 24 hours and in 80% of patients at 3 months. At 3 months, 82.5% of patients achieved complete clinical recovery. Rebound post-treatment headaches occurred in 32.5% of patients but resolved within 7 days. The morbidity rate was 0%. CONCLUSIONS: Transvenous embolization of CSFVFs results in early and sustained clinical and imaging improvements in patients with SIH. These findings support the efficacy of this intervention as a primary treatment for CSFVFs.