Xanthogranulomatous cholecystitis: diagnostic performance of US, CT, and MRI for differentiation from gallbladder carcinoma.

Abstract

The purpose of this study is to evaluate the diagnostic performance of HRUS, CT, and MRI for differentiating xanthogranulomatous cholecystitis (XGC) from gallbladder (GB) cancer. Patients with surgically proven XGC (n=40) and GB cancer (n=44), who had undergone at least one HRUS (n=43), CT (n=82), or MRI (n=34) examination between 2000 and 2012, were included. Two radiologists retrospectively graded the likelihood of XGC or GB cancer using a 5-point confidence scale; they also assessed the imaging features. Statistical analyses were performed using ROC, ANOVA, and Fisher's exact test. Diagnostic performance of MRI was better than HRUS for differentiating XGC from GB cancer (AUCs=0.867 and 0.911 vs. AUCs=0.818 and 0.86). However, HRUS showed a better performance than CT (AUCs=0.818 and 0.86 vs. AUCs=0.806 and 0.84) with moderate to excellent agreement (κ=0.48-0.83). Statistically common findings for XGC included non-focal thickening, smooth GB wall, presence of intramural nodules, type I enhancement of wall, transient hepatic attenuation difference, and continuity of mucosa (p<0.05). Co-existence of gallstones (OR=16.5), non-focal thickening (OR=14.7), and collapsed lumen (OR=13.0) on HRUS, and type I enhancement on CT (OR=3.52) were independently associated with XGC (p<0.05). Although MRI showed a better performance than both HRUS and CT, HRUS showed a better performance than CT. The co-existence of gallstones, non-focal thickening, and collapsed lumen on HRUS was independently associated with XGC.