Diagnostic ultrasound of acute colonic diverticulitis by surgical residents.

Background: Recent studies have documented the feasibility of ultrasonography (US) to diagnose acute colonic diverticulitis (ACD). This prospective observational trial determined the sonomorphology of ACD and evaluated the diagnostic accuracy of routine US performed on admission by surgeons in training.

Methods: Fifty-seven consecutive patients with a confirmed episode of ACD were entered into this study, and the sonomorphology of the involved colon was assessed. US findings were compared to the results of the clinical evaluation and correlated to the clinicopathological outcome.

Results: The sonomorphology of ACD was characterized by segmental inflammatory transformation of the colon averaging 9.9 +/- 3.2 cm (range, 6-20) in length and visualized as target phenomena of a mean 3.5 +/- 0.8 cm (range, 2.4-4.8) width. Targets were caused by hypoechogenic thickening of the colonic wall of an average 7.7 +/- 2. 6 mm (range, 4-18). In 40% of cases, a hyperechogenic halo representing peridiverticulitis (average width, 2.3 +/- 0.6; range, 1.2-3 cm) was noted. Diverticula were seen in almost half of the cases. Of the 57 cases with confirmed ACD, the diagnosis was made by US in 48, for a global accuracy of 84.2%. US was false negative in nine patients, suggesting perforated appendicitis in five cases and acute appendicitis in one (the final diagnoses were perforated sigmoid diverticulitis in five cases and cecal diverticulitis in one case). In three patients, US was nondiagnostic.

Conclusion: In the hands of sonographically trained surgeons, ultrasound is a useful modality to image acute colonic diverticulitis. US reveals diagnostic sonomorphology in most cases of ACD and therefore facilitates early confirmation of the diagnosis and assessment of severity.