Can acute abdominal CT prioritize patients with suspected diverticulitis for a subsequent clean colonic examination?

The aim of this study was to investigate whether patients with diverticulitis can be prioritized with higher urgency for a subsequent full colonic examination based upon the emergency abdominal CT scan performed at the time of presentation.

All patients with a diagnosis of diverticulitis, hospitalized during 2006 and having a CT scan on admission and a subsequent 'clean colon' examination, were reviewed. The CT scan was reviewed by two independent and blinded senior radiologists (Radiologist A and Radiologist B) for signs inconsistent with diverticulitis and suggestive of malignancy. The patients were classified on the CT scan results into group 1 (normal findings, nontumour pathology or benign polyps < 1 cm) or group 2 (benign polyps ≥ 1 cm and cancer).

Ninety-three patients (83 in group 1 and 10 in group 2) were reviewed. Radiologist A suggested high-priority colonic examination in 18% and 50% of patients in groups 1 and 2, respectively, and Radiologist B in 63% and 90% of patients, respectively. There was a statistically significant interobserver difference, and also lower accuracy of Radiologist B compared with Radiologist A in predicting a subsequent 'clean colon' examination.

Use of an emergency acute CT scan at the time of diagnosis of diverticulitis to predict a clean colon examination for neoplasia is not reliable because there is a considerable degree of interobserver difference between radiologists.