Schematic time sequence diagram of the study protocol. Anesthetic preparation, induction of anesthesia, and the initial magnetic resonance imaging sequence lasted approximately 75 min. The pretreatment magnetic resonance imaging perfusion sequence lasted 5 min. Infusion of the study medication and the steady-state period until the desired effect on blood pressure was achieved lasted approximately 15 min. The posttreatment perfusion sequence (5 min) ended the magnetic resonance imaging examinations. Finally, the patient was transported to the surgical suite (approximately 20 min). Approximately 120 min passed from anesthesia induction until the patient was ready for surgery. Another 20 min elapsed before the subdural intracranial pressure measurement began.