Patients who empty their stomach slowly may have what we call "Slow gastric emptying" or "gastroparesis". These patients can have some changes in the thickness of their stomach wall. In addition, they may have loss of some important nerve cells in their stomach muscles. The loss of these cells can cause slow emptying of the stomach. Obtaining a sample from the stomach wall to examine the loss of these cells can help in diagnosing gastroparesis. Up to now, the only way to obtain a tissue sample from the stomach muscle was to undergo an operation in the surgery suite and be hospitalized for several days after the procedure. Usually, we obtain this sample while these patients are having a surgery for another purpose such as placement of a gastric stimulator (a machine which is inserted in the stomach wall to control the stomach rhythm and thus help the stomach to empty faster). Endoscopic ultrasound is an endoscope (a tube with a source of light and ultrasound installed in the tip of the tube) that can measure how thick the stomach wall is and can provide sample "biopsies" of the stomach wall which can be studied for the loss of these specialized muscles and cells.