Utility of CT Whirl Sign in Guiding Management of Small-Bowel Obstruction

Abstract

The purpose of this study was to examine the relation between the CT whirl sign and outcome among patients with a clinical and radiologic diagnosis of small-bowel obstruction (SBO). The cases of 453 patients who underwent abdominal CT because of clinical suspicion of SBO were reviewed retrospectively. Patients with a radiologic diagnosis of SBO were included. Management with surgery or medical therapy was correlated with the presence of the whirl sign and other radiologic findings. Statistical calculations were performed to determine the value of the whirl sign in predicting the type of management needed for SBO. According to CT criteria, 194 patients received a diagnosis of SBO and were included in the study. The whirl sign was identified on the CT scans of 40 of the 194 patients. Thirty-two of the 40 patients had SBO necessitating surgery, for a positive predictive value of 80%; 133 of 154 patients did not need surgery, for a negative predictive value of 86%. Fifty-three of 194 patients either underwent surgery or died of SBO during conservative therapy. The whirl sign was present on the CT scans of 32 of the 53 patients, for a sensitivity of 60%. One hundred thirty-three of 141 patients did not need surgery and did not have a whirl sign, for a specificity of 94%. The odds ratio for the whirl sign in predicting the presence of SBO necessitating surgery was 25.3 (95% CI, 10.3-62.3). A patient with the whirl sign on CT is 25.3 times as likely as a patient without the sign to have SBO necessitating surgery. The results suggest an important role of the whirl sign in assessment of treatment options for patients with clinical and radiologic signs of SBO.