A 79-year-old man is brought into hospital by his wife after falling in the bathroom and hitting his head. He did not lose consciousness before or after the fall. He has history of headaches and palpitations. Neurologic examination shows no abnormalities. Blood pressure is 110/75. A non-contrast CT of the head is shown below. Which of the following is the most appropriate next step in diagnosis?
Carotid duplex ultrasonography
Echocardiography
Electrocardiogram
Serum alkaline phosphatase
Urinary metanephrines
