Usefulness of contrast-enhanced US in the diagnosis of acute gangrenous cholecystitis: A comparative study with surgical and pathological findings.
To prospectively determine the usefulness of contrast-enhanced ultrasound (CEUS) in the diagnostic assessment of acute gangrenous cholecystitis, using histopathology as the reference method. The local institutional review board approved the study protocol, and all patients at enrollment provided a written informed consent. From December 2011 to July 2014, all patients with a clinical-sonographic diagnosis of acute cholecystitis underwent a CEUS examination. We included only patients who underwent cholecystectomies within 24-h of CEUS. Radiologists in the course of routine clinical care interpreted the US and CEUS images at the end of the examination, filling out a questionnaire. Two radiologists, blinded to the final diagnosis, independently reviewed the video CEUS sequences for the presence of defects of the gallbladder wall enhancement. Associations between the sonographic findings and histological gangrenous cholecystitis were evaluated by using univariate and multivariate logistic regression analysis. A total of 150 patients were analyzed. The histological diagnoses were 41 (27%) nongangrenous cholecystitis and 109 acute gangrenous cholecystitis (73%). Multivariate analysis of the predictive parameters at univariate analysis revealed that only leukocytosis, diabetes mellitus, lithiasis and defects of wall enhancement on CEUS were independent variables related to gangrenous cholecystitis. The presence of enhancement defects on CEUS enabled the diagnosis of the gangrenous form with sensitivity between 85 and 91% and specificity of 67.5-84.8%. Interobserver agreement for CEUS interpretation was good (median k value: 0.664; range, 0.655-0.680). Local or widespread absence of gallbladder wall enhancement on CEUS is associated with the presence of gangrenous acute cholecystitis.