Diagnostic Evaluation of Gastroparesis

Abstract

Gastroparesis is suspected in patients with postprandial abdominal pain, nausea, vomiting, or bloating, once peptic ulcer disease and gastric outlet obstruction are ruled out endoscopically. Multiple tests are available for the diagnosis of gastroparesis and include gastric emptying scintigraphy (GES), stable isotope breath test, wireless motility capsule, antroduodenal manometry, and other imaging modalities such as ultrasonography and magnetic resonance imaging (MRI). While GES is the gold standard, each of those tests provides different advantages and limitations to their use clinically. GES entails the ingestion of a radiolabeled solid meal and measuring the percentage of radioactivity remaining in the stomach at 0, 1, 2, and 4 hours after meal ingestion. It is considered delayed if there is >60% retention at 2 hours and/or >10% retention at 4 hours. Stable isotope breath test is commonly used and relies on the conversion of an ingested 13C-labeled substrate to 13CO2, which is exhaled from the lungs and measured by breath tests at 30 minutes intervals. It requires healthy subjects for proper absorption and metabolization of 13C labeled to 13CO2. The wireless motility capsule, approved by the US Food and Drug Administration to evaluate for gastric and bowel transit times in patients with suspected slow transit constipation, has the major advantage of assessing extragastric motility which can alter management options. Ultrasonography and magnetic resonance imaging are mostly used in research settings as they require significant skills and expertise.