The stomach is a muscular bag which relaxes with meals. The muscles also contract rhythmically to mix and grind the food, and eventually propel it into the small intestine through the pylorus. Disturbances of these muscular actions can give rise to important symptoms, particularly bloating nausea and vomiting. These symptoms can be due to inflammation of the lining of the stomach (with or without blockage). These conditions are usually detected and excluded by X-ray studies (barium meal) and upper endoscopy. Disorders of the muscles of the stomach can be tested in other ways.
Gastric emptying studies help to evaluate how quickly food is emptied into the intestine through the pylorus. The test is simple. The patient eats scrambled eggs which have been mixed with a very small dose of radioactivity. Scans are then taken to see how much of the eggs remain in the stomach. Usually about half has passed into the intestine within 90 minutes. Anything longer than 110 minutes implies poor gastric emptying function. Medicines can be given by intravenous injection to test whether they are effective in improving emptying (and can then be given by mouth).