Right colonic diverticulitis: US and CT findings--new insights about frequency and natural history.

PURPOSE: To evaluate how the use of ultrasonography (US) and computed tomography (CT) has changed insights on the frequency and natural history of right colonic diverticulitis.

MATERIALS AND METHODS: Clinical findings, US and CT images, and clinical and surgical records in 44 patients with a final diagnosis of right colonic diverticulitis seen over 11 years were retrospectively studied.

RESULTS: Of the 44 patients, three underwent diverticulectomy, and 41 were successfully treated conservatively. Follow-up US demonstrated a consistent change in the pattern of the findings of diverticulitis over time, with eventual spontaneous evacuation of the contents of the inflamed diverticulum into the colonic lumen. Five patients had recurrent symptoms; two of them underwent elective surgery. The frequency of right colonic diverticulitis was one in 34 appendectomies, which is nine times higher than that reported to date.

CONCLUSION: Right colonic diverticulitis is more common than has been previously reported. US and CT findings are characteristic and show a consistent pattern of changes over time. The natural history is benign, and surgical intervention can be avoided in the vast majority of patients.