Diagnostic performance and useful findings of ultrasound re-evaluation for patients with equivocal CT features of acute appendicitis.

Research paper by Mi Sung MS Kim, Heon-Ju HJ Kwon, Kyung A KA Kang, In-Gu IG Do, Hee-Jin HJ Park, Eun Young EY Kim, Hyun Pyo HP Hong, Yoon Jung YJ Choi, Young Hwan YH Kim

Indexed on: 04 Nov '17Published on: 04 Nov '17Published in: The British journal of radiology


To evaluate the diagnostic performance of ultrasound (US) and to determine which US findings are useful to differentiate appendicitis from non-appendicitis in patients who underwent US re-evaluation due to equivocal computed tomography (CT) features of acute appendicitis.Sixty-two patients who underwent CT examinations for suspected appendicitis followed by US re-evaluation due to equivocal CT findings were included. Equivocal CT findings were considered based on the presence of only one or two findings among the CT criteria, and US re-evaluation was done based on a pre-defined structured report form. The diagnostic performance of US and independent variables to discriminate appendicitis from non-appendicitis were assessed.There were 27 patients in the appendicitis group. The overall diagnostic performance of US re-evaluation was sensitivity of 96.3%, specificity of 91.2%, and accuracy of 91.9%. In terms of the performance of individual US findings, probe-induced tenderness showed the highest accuracy (86.7%) with sensitivity of 74% and specificity of 97%, followed by non-compressibility (accuracy 71.7%, sensitivity 85.2%, and specificity 60.6%). The independent US findings for discriminating appendicitis were non-compressibility (p = 0.002) and increased flow on the appendiceal wall (p = 0.001).US re-evaluation can be used to improve diagnostic accuracy in cases with equivocal CT features for diagnosing appendicitis. The presence of non-compressibility and increased vascular flow on the appendix wall are useful US findings to discriminate appendicitis from non-appendicitis. Advances in knowledge: US re-evaluation is useful to discriminate appendicitis from non-appendicitis when CT features are inconclusive.