Abdominal wall thickness is not useful to predict appendix visualization on sonography in adult patients with suspected appendicitis

Purpose To evaluate clinical and imaging factors for potential use in predicting appendix visualization on sonography (US) of adult patients with suspected appendicitis. Methods All adult patients who underwent appendiceal US from January through June 2010 were included in this retrospective study. Clinicopathological records were reviewed for age, sex, weight, body mass index, symptom duration, Alvarado score, surgicopathologic diagnosis, and disposition. Imaging records were collated for abdominal thicknesses, appendix visualization, and impression. The definitive diagnosis was made on pathologic evaluation. Results Eighty‐six patients (68 women; median age, 35.5 years; age range, 16–86 years) met the inclusion criteria. The patients' mean weight was 56 kg; body mass index, 22.4; duration of symptoms, 24 hours; and Alvarado score, 6.5. Of the 86 patients, 37 (43%) had appendicitis. The appendix was visualized on US in 27 patients, of whom 25 had appendicitis; the appendix was not visualized in 59 patients, of whom 12 had appendicitis. There was no correlation between the clinical factors studied, the abdominal fat thickness (10.9 versus 10.7 mm; p = 0.90), or the abdominal wall thickness (16.9 versus 17.3 mm; p = 0.76) between patients with a US‐visualized appendix and those whose appendix was not visualized on US. Conclusions Abdominal thicknesses and other factors are not predictive of appendix visualization on US examination of adults with suspected appendicitis. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:269–276, 2015