Darren Lu MD, Presenter: Nothing to Disclose

Hisham A. Tchelepi MD, Abstract Co-Author: Nothing to Disclose

To recognize ultrasound (US) as the first step in evaluating reproductive-aged women with suspected acute appendicitis and to stress its role in eliminating the need for unnecessary radiation exposure.

A retrospective review was conducted of women ages 14 to 45 (mean of 28.4) presenting with right lower quadrant pain suspicious for acute appendicitis. All cases had an initial right lower quadrant ultrasound. Subsequent CT scans were performed as clinically indicated by the ordering physicians. All cases that proceeded to surgery had pathologic confirmation.

158 cases were reviewed. In 23 cases (14.6%), a normal appendix was identified on US. 2 of those cases had a follow up CT performed, both showing a normal appendix. 27 cases (17.1%) demonstrated a dilated, noncompressible appendix consistent with acute appendicitis on US. 8/27 (29.6%) had follow up CT, 7 of which confirmed acute appendicitis. One case proved to be cecal diverticulitis with a normal appendix. All cases of acute appendicitis were confirmed on pathology except one, which was perforated and managed medically. 108 cases (68.3%) were non-diagnostic in which the appendix was not identified. 34 of those had a CT demonstrating a normal appendix. 17/34 (50%) had alternative diagnoses including pyelonephritis, hemorrhagic/ruptured ovarian cysts, teratoma, fibroids, and hydrosalpinx. Our results demonstrate that US has a positive predictive value of 95.8% and a negative predictive value of 100% when an appendix was identified, which are similar to the previously reported data for CT. None of the patients with a non-diagnostic US were subsequently diagnosed with acute appendicitis on CT or clinically. Using the calculator from www.xrayrisk.com, for a female with an average age of 28.4 and DLP of 790 mGy-cm (values from our study population), the total effective dose of a CT abdomen and pelvis is 14.22mSv causing a 1/499 additional risk of cancer.

This study demonstrates that US plays a significant role in the reduction of radiation dose to our study population of reproductive-aged women. Additionally, US of the appendix in patient presenting with acute right lower quadrant pain can be dependable and reliable for diagnosis.

Ultrasound should be considered for the initial evaluation of suspected acute appendicitis, especially in reproductive-age women to decrease radiation exposure.

Lu, D, Tchelepi, H, Radiation Reduction in Reproductive-Aged Women for Suspected Acute Appendicitis: A Look at Ultrasound versus Computed Tomography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045431.html