Should Small Sliding Hiatal Hernias Be Reported at CT Colonography?

OBJECTIVE: The objective of our study was to determine whether colonic distention at CT colonography (CTC) induces small incidental sliding hiatal hernias. MATERIALS AND METHODS: This study evaluated for the presence and, if present, the size (small, moderate, or large) of sliding (type 1) hiatal hernias in 3126 consecutive asymptomatic adults (mean age ± SD, 57.0 ± 7.4 years) undergoing screening CTC. Colonic distention was achieved with automated continuous CO(2) delivery. As an internal control, standard CT studies (i.e., without colonography technique) were available for comparison in 123 individuals with a hernia present at CTC. In addition, the prevalence of hiatal hernia was assessed in an external control group of 488 adults (mean age, 60.8 years) undergoing abdominal CT without colonic distention. The Fisher exact test was used to test for statistical significance. RESULTS: Hiatal hernias were present in 47.8% (1495/3126) of adults at screening CTC (86% small, 13% moderate, 1% large). Abdominal CT of the 123 internal control subjects showed resolution of the hernia in 64.2% (79/123) of cases and was smaller in an additional 12 cases. The prevalence of sliding hiatal hernias in the external control group was 23.8% (116/488), significantly lower than in the CTC screening cohort (p < 0.0001). After applying an empiric correction factor based on results from the internal control group to account for technique-induced hernias, the estimated prevalence for the CTC cohort more closely matched that for the external control subjects. CONCLUSION: Our findings suggest that small sliding hiatal hernias are commonly induced by colonic distention at CTC and should probably not be reported to avoid inappropriate diagnosis, workup, or treatment.