Utility of CT Findings in the Diagnosis of Cecal Volvulus.
AJR Am J Roentgenol. 2017 Oct;209(4):762-766. doi: 10.2214/AJR.16.17715. Epub 2017 Aug 4. Dane B1, Hindman N1, Johnson E1, Rosenkrantz AB1.
OBJECTIVE: The objective of our study was to assess the utility of CT features in the diagnosis of cecal volvulus.
MATERIALS AND METHODS: Forty-three patients undergoing CT for cecal volvulus and with surgical or clinical follow-up were included. Two radiologists (11 years and 1 year of experience) evaluated CT examinations for the following: whirl sign, abnormal cecal position, "bird beak" sign, severe cecal distention, mesenteric engorgement, a newly described "central appendix" sign (defined as abnormal appendix position near midline), and overall impression for cecal volvulus. Univariable and multivariable assessments were performed. Patients with CT examinations in which the appendix was not visible were excluded from calculations involving the central appendix sign.
RESULTS: Fifty-one percent (n = 22) of patients had cecal volvulus. All CT findings were significantly more common in patients with cecal volvulus (p < 0.01) other than mesenteric engorgement for reader 1 (p = 0.332). Readers 1 and 2 identified the central appendix sign in 92.9% and 92.3% of patients with volvulus versus in 37.5 and 31.1% of patients without volvulus. The whirl sign exhibited a sensitivity for cecal volvulus of 90.9% for reader 1 and 95.5% for reader 2, and a specificity of 61.9% for both readers. Abnormal cecal position exhibited a sensitivity of 90.0% for reader 1 and 100.0% for reader 2 and a specificity of 66.7% and 38.1%. The bird beak sign exhibited a sensitivity of 86.4% for reader 1 and 100.0% for reader 2 and a specificity of 85.7% and 71.4%. Severe cecal distention exhibited a sensitivity of 100.0% for both readers and a specificity of 81.0% and 61.9%. Mesenteric engorgement exhibited a sensitivity of 40.9% for reader 1 and 100.0% for reader 2 and a specificity of 76.2% and 71.4%. The central appendix sign exhibited a sensitivity of 92.9% for reader 1 and 92.3% for reader 2 and a specificity of 62.5% and 68.8%. Overall impression exhibited a sensitivity of 100.0% for both readers and a specificity of 76.2% and 57.1%. At multivariable analysis, the AUC for cecal volvulus ranged from 0.787 to 0.931, and the whirl sign was an independent predictor of volvulus for both readers (p ≤ 0.014); the central appendix sign was also an independent predictor in patients with a visualized appendix for reader 2 (p ≤ 0.001).
CONCLUSION: CT exhibited high diagnostic performance and very high sensitivity for cecal volvulus. The whirl sign was a significant independent predictor of volvulus for both readers.