Asymptomatic pneumatosis at CT colonography: a benign self-limited imaging finding distinct from perforation.

OBJECTIVE: The purpose of our study was to report the prevalence and clinical course of colonic pneumatosis at CT colonography (CTC). MATERIALS AND METHODS: The study population consisted of 5,368 adults (mean age, 57.4 years; 2,807 women, 2,561 men) undergoing CTC. Pertinent medical history, CTC imaging studies, and clinic course were reviewed for all cases in which pneumatosis (i.e., air in the bowel wall) was prospectively identified. RESULTS: Colonic pneumatosis was seen in six (0.11%) of 5,368 total CTC studies. No cases of small-bowel pneumatosis were identified. There were no cases of frank colonic perforation in this series. All six cases of pneumatosis involved the use of automated carbon dioxide for colonic distention (0.17%; six of 3,451 cases). Pneumatosis was not seen in 1,917 cases with manual room air insufflation (p = 0.095). The right colon was involved in all cases, typically revealing a thin curvilinear configuration with variable circumferential extension. In one of the six cases, a frankly cystic appearance (pneumatosis cystoides intestinalis) was seen in the left colon. No free intraperitoneal gas, portomesenteric venous gas, or distant extraperitoneal gas was present in any case. No unexpected abdominal symptoms developed during the CTC examination, and all six patients were asymptomatic after the procedure. None of the patients required any treatment or intervention. CONCLUSION: Asymptomatic right-sided colonic pneumatosis is a rare self-limited condition associated with carbon dioxide delivery at CTC. This benign imaging finding should not be confused with symptomatic perforation.