Diagnostic imaging of suspected appendicitis in pregnant women: comparison of CT to ultrasonography

Purpose: To compare the sensitivity and specificity of CT versus ultrasonography for the diagnosis of appendicitis in a population of pregnant women. Materials and methods: Radiology records (1988–1999) were searched for results of examinations performed on pregnant patients with suspected appendicitis. Subjects included only women with known intrauterine pregnancies. Thirty-two pregnant women were identified who had been studied by CT, ultrasound, or both. Ten patients had undergone focused abdominal CT with colon contrast, while 29 had undergone abdominal or pelvic ultrasonography with attention to the appendix. Results were compared to surgical pathology or follow-up findings. Results: CT sensitivity was 100 %, specificity 100 %, positive predictive value (PPV) 100 %, negative predictive value (NPV) 100 % and accuracy was 100 %. Ultrasound sensitivity was 100 %, specificity 83 %, PPV 50 %, NPV 100 %, and accuracy 21 %. Conclusion: In this small cohort of gravid females with suspected appendicitis, the sensitivity of focused abdominal CT with colon contrast was equal to that in the nonpregnant patient. In contradistinction to this, abdominal ultrasonography was frequently indeterminate. We hypothesize that ultrasonography is less accurate due to body habitus and the variable location of the appendix during pregnancy.