Evaluation of early sonographic predictors of gangrenous cholecystitis: mucosal discontinuity and echogenic pericholecystic fat

Purpose To identify early sonographic features of gangrenous cholecystitis. Materials and methods 101 patients with acute cholecystitis and a pre-operative sonogram were retrospectively reviewed by three radiologists in this IRB-approved and HIPAA-compliant study. Imaging data were correlated with histologic findings and compared using the Fisher’s exact test or Student t test with p < 0.05 to determine statistical significance. Results Forty-eight patients had gangrenous cholecystitis and 53 had non-gangrenous acute cholecystitis. Patients with gangrenous cholecystitis tended to be older (67 ± 17 vs 48 ± 18 years; p = 0.0001), male (ratio of male:female 2:1 vs 0.6:1; p = 0.005), tachycardic (60% vs 28%; p = 0.001), and diabetic (25% vs 8%; p = 0.001). Median time between pre-operative sonogram and surgery was 1 day. On imaging, patients with gangrenous cholecystitis were more likely to have echogenic pericholecystic fat ( p = 0.001), mucosal discontinuity ( p = 0.010), and frank perforation ( p = 0.004), while no statistically significant differences were seen in the presence of sloughed mucosa ( p = 0.104), pericholecystic fluid ( p = 0.523) or wall striations ( p = 0.839). In patients with gangrenous cholecystitis and echogenic pericholecystic fat, a smaller subset had concurrent mucosal discontinuity (57%), and a smaller subset of those had concurrent frank perforation (58%). The positive likelihood ratios for gangrenous cholecystitis with echogenic fat and mucosal discontinuity were 4.6 (95% confidence interval 1.9–11.3) and 14.4 (2.0–106), respectively. Conclusion Echogenic pericholecystic fat and mucosal discontinuity are early sonographic findings that may help identify gangrenous cholecystitis prior to late findings of frank perforation. Graphic abstract