Abdominal Sonography of Suspected Appendicitis

Sim, Won Sup; Sim, Myungsuk

Abstract

PURPOSE
To decrease the high negative appendectomy rate, in addition to the traditional history-taking, physical examination, and laboratory findings, additional sensitive and specific examinations are necessary. The authors conducted a study to evaluate the value of ultrasonographic examination in the diagnosis of acute appendicitis in patients with clinically suspected appendicitis.
METHODS
During 18 months from July 1, 1998 through December 31, 1999, a total of 290 patients were enrolled into the study. Altogether 110 abdominal sonographic examinations were performed by the staff radiologist, in all cases of clinically suspected appendicitis. The improvement of diagnostic accuracy was compared with the historical control group of 240 patients during the period of 18 months from January 1, 1997 through June 30, 1998.
RESULTS
Clinical diagnosis (without sonographic examination) was made in 180 patients (157 appendicitis, and 23 non-appendicitis). Negative appendectomy was performed in 24 patients. Sonographic diagnosis was made in 110 patients with clinically suspected appendicitis (91 appendicitis, and 19 non-appendicitis). Negative appendectomy was done in 9 patients. Nineteen patients without positive sonographic findings of appendicitis could be spared the negative appendectomy. Abdominal sonography for detecting acute appendicitis had a sensitivity of 100.0%, a specificity of 67.9%, an accuracy of 91.0%, a positive predictive value of 90.1%, and a negative predictive value of 100.0%. By adding ultrasonographic examinations in all cases of clinically suspected appendicitis, diagnostic specificity was increased significantly over the historical control group (P<0.01).
CONCLUSIONS
Although the value of meticulous history- taking, physical examination, and laboratory tests cannot be overemphasized, our experience suggests that patients with clinically suspected appendicitis should routinely undergo abdominal sonographic examinations, performed by experienced radiologists and surgeons, to further decrease the negative appendectomy rates.