Testing of the Stomach
Tests used to evaluate patients with delayed or altered gastric emptying usually include upper endoscopy (EGD) to look inside the stomach through an endoscope passed through the mouth into the esophagus and stomach, and gastric emptying scintigraphy (a nuclear medicine study) to measure how quickly food leaves the stomach. The test of gastric emptying involves eating food that has a radioactive substance added to it, so that the rate of emptying of the stomach can be measured with a special camera.
Another, less frequently used test is the electrogastrogram , which measures small electrical currents that come from the stomach muscle and that indicate whether the 3 per minute contractions of the lower stomach are occurring normally. The contractions of the stomach can also be measured directly by passing a tube with pressure sensors on it down the nose and into the stomach.
A newer device that uses a wireless capsule, which the patient swallows has recently been introduced to measure gastric emptying. The device monitors and records data on a small portable receiver as the capsule passes through the GI tract. The data collected is later evaluated by the doctor.
In the absence of an ulcer or obstruction, a diagnosis of gastroparesis is confirmed by testing to see how quickly food leaves the stomach. The current standard international protocol is the method called scintigraphy that measures the rate of emptying, periodically, over a period of 4 hours.
In 2006 a monitoring system using a wireless capsule was approved in the U.S. by the Food and Drug Administration (FDA) and in Canada by the Medical Devices Bureau. This involves a wireless, ingestible capsule for the assessment of gastric acidity, gastric emptying, and total GI transit time. Information thus provided may assist doctors in diagnosing gastroparesis and other gastrointestinal motility disorders.
A gastric emptying study (see above) can show whether there is poor emptying of the stomach. The other gastric motility disorders are more difficult to detect, but scientists have developed a computer-controlled pump called the barostat which can show (1) whether the upper stomach relaxes adequately during eating, and (2) how much filling of the stomach it takes to cause pain or discomfort.