Sarah Bixby MD, Presenter: Nothing to Disclose

Brian C. Lucey MBBCh, Abstract Co-Author: Nothing to Disclose

Jose Varghese, Abstract Co-Author: Nothing to Disclose

Jorge Andres Soto MD, Abstract Co-Author: Nothing to Disclose

To determine the ability of MDCT to identify perforation in patients with acute appendicitis.

Pathology records of all patients whose appendix was removed over a two-year period (June 2002-June 2004) were obtained. A study population was created including only those patients who had a CT scan on a multi-detector scanner (slice thickness 2.5-3.2mm with both oral and intravenous contrast) less than 24 hours before surgery for suspected acute appendicitis. A total of 206 patients were included in the study. Pre-operative CT scans were evaluated by two radiologists. Parameters documented included size and location of appendix, presence of appendicolith, free fluid or abscess, free air, mural enhancement defects, peritonitis or mesenteric inflammation, and size and number of right lower quadrant lymph nodes. Finally, each study was determined to represent either perforated or non-perforated appendicitis, and this imaging designation was compared to surgical and pathology reports, which represented the gold standard.

The sensitivity, specificity, PPV and NPV of MDCT in detecting the presence of perforation in acute appendicitis was 47%, 96%, 81% and 84% respectively. When free air or peri-appendiceal abscess was present, this was always associated with perforation. The size of the appendix was greater in patients with perforation, with an average diameter of 13.7mm compared to 11.7mm in non-perforated patients [P < 0.001]. The presence of an appendicolith, free fluid, RLQ lymph nodes, and enhancement defects in the wall of the appendix were not statistically significant predictors of perforation.

While MDCT is very specific for the diagnosis of perforated appendicitis, its sensitivity is poor. Unless free air or peri-appendiceal abscess is present, MDCT cannot reliably determine if perforation is present since acute perforated appendicitis and suppurative, non-perforated appendicitis share many of the same imaging characteristics.

Bixby, S, Lucey, B, Varghese, J, Soto, J, MDCT as a Predictor of Perforation of Acute Appendicitis: Are We as Good as We Think?.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4407028.html