Alexander Nguyen, Abstract Co-Author: Nothing to Disclose

Emily M. Webb MD, Abstract Co-Author: Nothing to Disclose

Joseph Stengel DO, Presenter: Nothing to Disclose

Jane Wang MD, Abstract Co-Author: Nothing to Disclose

Antonio C. Westphalen MD, Abstract Co-Author: Nothing to Disclose

Fergus V. Coakley MD, Abstract Co-Author: Nothing to Disclose

To determine the negative appendectomy rate (NAR) in patients with and without preoperative CT imaging.

We reviewed CT reports of 2283 patients imaged for suspected appendicitis between July 1, 2002 to June 30, 2007 and identified 421 patients (225 men, 196 women) who underwent subsequent appendectomy. We reviewed pathology records of appendectomy specimens to identify 46 patients (41 men, 5 women) who underwent appendectomy without preoperative imaging over the same time period. Data was compared between groups using Fisher’s exact test.

The negative appendectomy rate was 19/421 or 4.3% among patients with preoperative CT. 46 patients underwent appendectomy without preoperative imaging (CT, MR or US), and in this group the NAR was significantly higher (4/46 or 13%, p<0.03) Among men, the NAR was 4/225 or 1.8 % for those with preoperative CT versus 5/41 or 12.2% for those without (p<0.01). Among women, the NAR was reduced in those with preoperative CT (7.7% with CT, versus 20% without), but the difference was not statistically significant (p=0.34). <0>

This study demonstrates an overall decrease in the NAR with preoperative CT (4.3% versus 13%). Notably, the NAR was also significantly decreased among men (1.8% versus 12.2%), but not in women.

Past studies have suggested that preoperative CT is only efficacious in decreasing the NAR among women, but our study demonstrates a clear benefit among men as well.

Nguyen, A, Webb, E, Stengel, J, Wang, J, Westphalen, A, Coakley, F, The Negative Appendectomy Rate: Who Benefits from Preoperative CT?.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8014341.html