Interested in imaging modalities and their effectiveness in diagnostics?  Read the abstract and click the link below for our newest accepted publication!

Ultrasound vs CT for Diagnosing Acute Appendicitis and Appendicitis Treatment Altering Conditions

Christopher Borowy, MS-IV1*, Luke Rond, D.O2, John Ashurst, D.O2, and Stefan Merrill, M.D2
1Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USA
2Department of Emergency Medicine, Kingman Regional Medical Center, Kingman, AZ, USA

Introduction: Acute appendicitis is the most common cause of atraumatic abdominal pain in children over 1 year of age. Even though diagnostic imaging modalities have evolved over the past 20 years, accurate diagnosis of acute appendicitis still presents as a challenge. Computed tomography (CT) is currently the most commonly used radiographic test for acute appendicitis. Unlike CT, ultrasound (US) does not require ionizing radiation which is harmful to the patient. Even though the specificity of US has been well studied in acute appendicitis, CT is still commonly requested after a positive US. Till date, there has been no published research evaluating the utility of US in changing management in appendicitis.

Purpose: The purpose of the study is to compare the ability of US and CT to diagnose pathology proven acute appendicitis and to predict Appendicitis Treatment Altering Conditions (ATAC).

Methods: This is a retrospective cohort study that compares the positive predictive value (PPV) and the ATAC rate of US and CT when diagnosing acute appendicitis.

Results: There were 432 appendicitis cases reported between 1 October 2012 and 30 June 2017. Of those cases, 409 were diagnosed by CT and 23 were diagnosed by US. The PPV of both modalities was above 90% (CT = 97%, US = 95%), and the ATAC rates were statistically similar (CT = 14%, US = 22%, P = 0.21).

Conclusion: The study supports that a positive US for appendicitis is as diagnostic as a positive CT. Therefore, adding on a CT scan after a positive US does not help recognize other sources of intra-abdominal pathology that would negate doing a laparoscopy.

Keywords: US, ultrasound, CT, CAT, ATAC, appendicitis, sensitivity, positive predictive value, PPV