preoperative abdominal ultrasonography: validity and it's diagnostic errors in suspected appendicitis

aim : the aim of this study is to evaluate the accuracy of preoperative abdominal ultrasonography in suspected appendicitis, and equivocal exam. background : acute appendicitis is a common problem and occasional challenging diagnosis in emergency department of every general hospital. patients and methods : within a period of one year from march 2007 through march 2008, all patient with suspected appendicitis and equivocal physical exam admitted in emergency department of taleghani hospital undergone preoperative sonography and then results compared with intra operative finding and final pathologic report. results : among totally 106 urgent appendectomies performed in this period of time, 65 (61.3%) of patients had highly suspicious physical finding and underwent appendectomy directly without delay. of the remainder, 41 (38.7%) with equivocal exam, preoperative ultra sonography were performed and then underwent appendectomy and entered in this study. of totally 41 patients, 25 (61%) were male and 16 (39%) were female. preoperative ultra sonography were highly suggestive appendicitis in 15 (36.59%) of patients, that correlate with intra operative finding and final pathologic results of appendicitis in 14 (93.3%), eight (19.51%) patients with final operative finding of appendicitis had also preoperative sonography suggestive of appendicitis. among 18 (43.9%) patients with preoperative ultra sonography of normal appendix or inability for visualization appendix, 14 (77.7%) had final pathologic diagnosis of appendicitis. sensitivity, specificity, positive and negative predictive values of preoperative sonography were 73.3%, 75%, 95.6% and 27.3%, respectively. conclusion : preoperative ultra sonography as a tool in evaluation of patients with equivocal physical findings, suspicious of appendicitis, has a moderate accuracy in this setting, considering ultra sonography as operator- dependent measure.