Early small bowel activity may predict rapid gastric transit on gastric emptying scintigraphy

Objectives: In patients with symptoms of gastroparesis (early satiety, bloating, nausea/vomiting), gastric emptying scintigraphy can confirm the diagnosis or propose a common alternate etiology: Rapid gastric transit. In patients with rapid gastric transit, we noticed in our clinic that many had a portion of the radioactive meal in the small bowel on images taken immediately after meal ingestion. In this study, we evaluate whether meal in the small bowel on initial images of a standard four-hour gastric emptying scintigraphy protocol can predict rapid gastric transit or exclude gastroparesis.

Methods: IRB approval was obtained. Retrospective analysis of 200 patients who underwent 4-hour gastric emptying scintigraphy using a standardized egg sandwich meal was performed. One nuclear medicine physician evaluated initial (time zero) anterior and posterior images for the presence of Tc-99m sulfur colloid labeled solid meal beyond the stomach in the small bowel loops. Gastric retention percentages at two and four hours were recorded. Patients under 18 yrs old, with prior gastrointestinal surgery, and/or solid meal consumption <70% were excluded.

Results: Out of 200 patients reviewed, 70 had activity within the small bowel on initial images. Out of these 70, 26 were excluded due to reasons listed above. The remaining 44 patients were included in the analysis. Of the 44 patients with meal in the small bowel at time zero, 33 (75%) had rapid gastric emptying at 2 hours and normal emptying at 4 hours. Only three of the 44 patients (6.8%) had mildly delayed emptying (11%, 14% and 19%) at 4 hours.

Conclusions: This study shows that in a small series of patients with early emptying of a radioactive meal into the small bowel, 75% were ultimately diagnosed with rapid gastric transit. This finding could be a useful clinical tool to help diagnose rapid gastric transit and to potentially decrease imaging time in patients. Further studies are warranted to reach statistical significance.