16.  A middle-aged man with a body mass index (BMI) of 28 is…

16.  A middle-aged man with a body mass index (BMI) of 28 is complaining of sharp burning pain that starts at the middle of the right buttock and radiates down the posterior aspect of the thigh and lower leg. He is complaining of weakness of the ankle and foot that is interfering with walking. The pain started three months ago and is becoming more frequent and severe. It is aggravated by prolonged sitting which is interfering with his job as a truck driver. His past medical history is positive for hypertension and metabolic syndrome. The patient is taking lisinopril-hydrochlorothiazide (Zestoretic) 10mg/12.5 mg once a day. Which of the following tests is appropriate to further evaluate the patient’s symptoms?