Assessment of Small-bowel and Colonic Transit on Routine Gastric Emptying Scintigraphy: Establishment of Reference Values.

Purpose of the study: The primary objective was to establish the reference values for small-bowel and colonic transit within the context of the routine standard solid meal gastric emptying scintigraphy (GES). The secondary objective was to compare the small-bowel and colonic transit between the anterior view and geometric mean methods.

Materials and methods: Twenty-nine healthy controls underwent routine GES, with additional imaging at 24 h if feasible. Small-bowel transit was assessed using the index of small-bowel transit (ISBT), calculated as the ratio of terminal ileal reservoir counts to total abdominal counts at 4 h. Colonic transit was evaluated using the colonic geometric center (CGC) by dividing the large bowel into four segments, with an additional fifth segment accounting for the eliminated counts. Reference values were established based on the fifth percentile or mean ± 1.96 standard deviations. Rapid small-bowel transit was visually determined. Paired Samples t-test or Wilcoxon signed-rank test, as applicable, was used to compare the small-bowel and colonic transit between the anterior view and geometric mean methods. For comparing small-bowel and colonic transit between females and males, the Independent samples t-test or Mann-Whitney U-test was applied, as appropriate. The correlation between age and small-bowel and colonic transit was assessed using Spearman's rank correlation analysis.

Results: The reference value for small-bowel transit using the geometric mean method was established as ISBT >37% at 4 h, whereas rapid small-bowel transit was defined as the first visualization of activity in the cecum-ascending colon within 2 h. For colonic transit, the reference range was established as CGC 2.8-4.4 at 24 h. Comparing the anterior view and geometric mean methods, there were no significant differences in ISBT and CGC values (P ≥ 0.125). Gender did not affect small-bowel and colonic transit in both methods (P ≥ 0.378), and age showed no significant correlations (P ≥ 0.053).

Conclusion: This study determined the reference values for small-bowel and colonic transit in the Indian population using routine GES, avoiding the need for additional complex procedures. The results may be generalized to the Indian population, emphasizing the importance of assessing small-bowel and colonic transit in patients with normal gastric emptying parameters to enhance gastrointestinal transit evaluation.