No abstract

The clinical value of high-resolution real-time sonography for the diagnosis of acute and complicated appendicitis was prospectively investigated in 857 patients admitted with suspected appendicitis. The ultrasound findings were correlated with history and physical examination on admission. Sonography was able to make the diagnosis of appendicitis with a sensitivity of 89.7%, a specificity of 98.2%, an overall accuracy of 96.3%, and a positive and negative predictive value of 93.6% and 97%, respectively. Routine use of ultrasound before making therapeutic decisions has reduced the rate of unnecessary laparotomies from 20.3% to 11.3%. In 48 (24.7%) of 194 patients with proven appendicitis, the disease had progressed to perforation at laparotomy. History and clinical findings on admission classified 30 (62.5%) of these patients as "highly suspect;" however, 9 (18.8%) were classified as "equivocal" and 9 (18.8%) as "very unlikely." Only half (48%) of the patients with appendiceal rupture had white blood cell counts higher than 13,000/mm3 or fever above 38 degrees C (50%). Sonography enabled the visualization of the inflamed appendix and/or appendicular abscess in 44 (91.7%) patients with perforation. In 47 of 48 patients with appendiceal rupture, the ultrasound-aided diagnosis was made on hospital admission. Thus, the incidence of complicated appendicitis (24.7%) in our study population must be attributed to disease progression before admission and preclinical diagnostic delay.

In a prospective study 404 unselected patients suspected of having acute appendicitis were examined by ultrasound, the results being compared with the initial clinical findings. Acute appendicitis was established in 27.2%, confirmed by histology. The overall accuracy of ultrasonography in relation to the diagnosis of appendicitis was 95.5%, 95.1% when positive, 95.7% when negative. An acutely inflamed appendix could not be demonstrated by ultrasound in 13 patients (sensitivity 88.2%), while in five there was a false-positive ultrasound result (specificity 98.3%). Complicated appendicitis with perforation occurred in 22 patients (20%): ultrasound sensitivity in this situation was 91%. Especially when the clinical picture was unclear (34.5% of all cases of appendicitis) a definitive diagnosis of acute appendicitis was made both earlier and more certainly by ultrasonography. Further-more, in many instances ultrasound was able to demonstrate other serious disease in the differential diagnosis from acute appendicitis. Negative laparotomy rate was lowered from 21.9% to 11.4% by taking into account ultrasonographic findings. Thus ultrasonography proved to be an important method as an imaging technique and in the differential diagnosis of acute appendicitis.