Usefulness of MRI Scoring System for Differential Diagnosis between Xanthogranulomatous Cholecystitis and Wall-Thickening Type Gallbladder Cancer.

PURPOSE: To define an MRI scoring system for differentiating xanthogranulomatous cholecystitis (XGC) from wall-thickening type gallbladder cancer (GBC) and compare the diagnostic performance of the scoring system with the visual assessment of radiologists.

MATERIALS AND METHODS: We retrospectively analyzed 23 and 35 patients who underwent abdominal MRI and were pathologically diagnosed with XGC and wall-thickening-type GBC after surgery, respectively. Three radiologists reviewed all MRI findings. We defined a scoring system using these MRI findings for differentiating XGC from wall-thickening type GBC and compared the area under the curve (AUC) of the scoring system with the visual assessment of radiologists.

RESULTS: Nine MRI findings showed significant differences in differentiating the two diseases: diffuse gallbladder wall thickening ( p < 0.001), mucosal uniformity ( p = 0.002), intramural T2-high signal intensity ( p < 0.001), mucosal retraction ( p = 0.016), gallbladder stones ( p < 0.001), T1-intermediate to high-signal intensity ( p = 0.033), diffusion restriction ( p = 0.005), enhancement pattern ( p < 0.001), and phase of peak enhancement ( p = 0.008). The MRI scoring system showed excellent diagnostic performance with an AUC of 0.972, which was significantly higher than the visual assessment of the reviewers.

CONCLUSION: The MRI scoring system showed better diagnostic performance than the visual assessment of radiologists to differentiate XGC from wall-thickening-type GBC.