Abstract
BACKGROUND: Occult pancreaticobiliary reflux (OPBR) is characterized by the absence of congenital anomalies at the pancreaticobiliary junction yet leads to altered bile composition and an increased incidence of gallbladder stones. AIM: To explore the computed tomography (CT) imaging characteristics of gallbladder stones in patients diagnosed with OPBR. METHODS: We analyzed 362 patients undergoing cholecystectomy (November 2020 to January 2022). Intraoperative bile samples were assayed for amylase (> 110 U/L indicated OPBR). CT features, including stone density and visibility, were compared between 54 OPBR and 308 controls. Stone attenuation (HU) was measured under standardized conditions (uCT-780, 120 kVp, 160 mAs). Logistic regression and receiver operating characteristic curve analysis identified independent OPBR predictors, forming a validated nomogram. RESULTS: OPBR patients exhibited significantly higher rates of CT-invisible stones (35.2% vs 12.3%) and uniform stones (87% vs 73.1%) along with lower overall stone density (P = 0.01). Logistic regression identified stone visibility, uniformity, and density as independent predictors. A nomogram integrating these features with patient age achieved high diagnostic accuracy (area under the curve = 0.71). CONCLUSION: CT imaging distinctly identifies gallbladder stone density, indicating a heightened risk of OPBR in patients with uniform and CT-invisible stones. Such imaging is crucial for preoperative assessments to evaluate potential recurrent biliary pathologies post-cholecystectomy.