Stephanie T. Chang MD, Presenter: Nothing to Disclose

R. Brooke Jeffrey MD, Abstract Co-Author: Research Consultant, InnerVision Ultrasound

Jarrett Rosenberg PhD, Abstract Co-Author: Nothing to Disclose

Eric West Olcott MD, Abstract Co-Author: Nothing to Disclose

To determine whether the ultrasound (US) presence of hyperechoic fat, hyperemia or an abnormal submucosal layer (SML) may be additionally predictive with appendiceal diameter in diagnosing acute appendicitis among pediatric and adult patients.

A total of 381 patients (292 pediatric patients and 89 adults defined as greater than 18 years in age) between the ages of 2-40 years undergoing US evaluation for appendicitis between December 2011-January 2013 with visualized appendices were included. US cases were retrospectively reviewed by two independent readers for the presence of hyperechoic fat (absent, unilateral, or circumferential), loss of the SML, or increased Doppler blood flow. Acute appendicitis was ascertained by surgery or clinical follow-up.

In a multivariate model including sex, age, maximum anterior-posterior diameter, fat, SML loss, and Doppler flow, only appendiceal diameter (OR 2.7, p<0.001), unilateral fat (OR 4.1, p=0.039), and circumferential fat (OR 7.7, p<0.001) demonstrated significant independent predictive value for diagnosing acute appendicitis in a population of adult and pediatric patients. Specifically, for borderline appendices measuring between 6-8 mm in diameter, the presence of circumferential fat significantly increased the likelihood of appendicitis (OR 9.0, p=0.006).

The US presence of hyperechoic fat, particularly circumferential fat, is the most important secondary finding to appendiceal diameter for diagnosing appendicitis in both pediatric and adult patients.

The presence or absence of hyperechoic fat on US evaluation for appendicitis is the most important finding for improving sensitivity and specificity in appendices between 6-8 mm in diameter.

Chang, S, Jeffrey, R, Rosenberg, J, Olcott, E, Revised Criteria for Ultrasound Diagnosis of Appendicitis: Importance of Hyperechoic Fat in Adult and Pediatric Patients with Appendices Measuring 6-8 mm in Diameter.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14005441.html