Dysphagia to Solids: Which Study Would You Choose?

Fear of dining outside the home brings this patient to see you. What's the best diagnostic tool?

A 35-year-old man presents with a 1-year history of intermittent dysphagia to solids. He is now worried about eating in restaurants for fear of food getting stuck in his esophagus. He occasionally takes an over-the-counter acid suppressant, which provides some symptom relief.

Which of the following procedures is most likely to establish a diagnosis?