Sonographic diagnosis of acute cholecystitis in patients with symptomatic gallstones

PURPOSE: The aim of the retrospective study was to assess the diagnostic ultrasound (US) criteria for acute cholecystitis in patients admitted for symptomatic gallbladder stones. METHODS: The medical records of 186 patients who had undergone cholecystectomy within 24 hours after an US examination were reviewed. Acute cholecystitis was defined on the basis of pathology findings. The correlation between standardized US signs and final diagnosis of acute cholecystitis was assessed with univariate and multivariate analyses. The diagnostic values of US based on the correlated signs were then calculated. RESULTS: The prevalence of acute cholecystitis was 52.7% (95% confidence interval [CI], 42.8-64.2). Three US signs were found to be predictive of acute cholecystitis: gallbladder distension, wall edema, and pericholecystic fluid collection. When none of the US signs were registered, sonography proved to have a 72.4% (95% CI, 59.1-83.3) negative predictive value. When registering two or three signs, sonography had positive predictive values of 78% (95% CI, 56.3-92.5) and 100% (95% CI, 58.9-100), respectively. With just one sign, the positive predictive value was 57.6% (95% CI, 47.2-67.4), and such a finding was furthermore observed in only 53.2% of the cases. CONCLUSIONS: The sonografic diagnosis of acute cholecystitis may be achieved by registering only three standardized US signs. Nevertheless, in patients admitted for symptomatic gallstones, US is of some utility in less than half of those patients.