PATHOLOGY

oM presents with a two-year history of episodic RUQ abdominal pain. pain occurs whenever he attempts to eat pizza or other fatty foods. previously undergone abdominal sonography and was found to have no gallstones, pericholecystic fluid, or gallbladder wall thickening. He also has undergoing EGD, which was unremarkable. His symptoms persist, and he sought you out as a second opinion. Your next best step in evaluating his pain further is: