Chronic Subdural Hematoma Treatment With Intra-Arterial Bevacizumab Injection

Inclusion Criteria: * Adult patients (≥18 years) * Radiographic evidence of chronic subdural hematoma, including 1. Persistence of subdural blood more than 10 days after index traumatic injury or event 2. Presence of mixed density blood 3. Presence of subdural membranes * Can obtain informed consent and Health Insurance Portability and Accountability Act (HIPAA) authorization. Exclusion Criteria: * Pregnant, breastfeeding, or unwilling to practice contraception during participation in the study. * Patients with concomitant intracranial pathology other than subdural hematoma (e.g., intracranial malignancy). * Patients with known hypersensitivity to bevacizumab. * Patients with radiographic evidence of mass effect. * Patients have focal neurological deficits attributed to subdural hematoma. * Patient had craniotomy or burr hole operative procedures performed in preceding two weeks prior to onset of subdural hematoma. * Secondary causes apart from trauma for the chronic subdural hematoma, such as underlying vascular abnormality or tumor. * Emergent surgical evacuation is required for the patient. * Non-convexity chronic subdural hematoma, as the middle meningeal artery will not supply this area. * Coagulation abnormalities, including platelet count \<100,000 and/or international normalized ratio of \<1.5 despite attempts for correction. * Patients with known contraindications for angiography. Patients with contrast allergy will be premedicated with diphenhydramine and steroids. * Patient has known active systemic infection or sepsis. * Patient has contradiction to anesthetic agents used for conscious sedation/monitored anesthesia care (MAC). * Patient has life expectancy of less than six months due to comorbid terminal conditions. * Patient has a premorbid modified Rankin score (mRS) of 5 or greater. * Concurrent participation in another research protocol for investigation of an experimental therapy.