# Cross-Modal Assessment of Post-Cholecystectomy Symptoms: Integrating MRCP Metrics with Upper Endoscopy

## TL;DR

This study shows that measuring the common bile duct with MRCP can help identify patients with post-cholecystectomy syndrome who are more likely to have biliary issues, reducing the need for invasive procedures.

## Contribution

The study identifies an MRCP-measured bile duct diameter threshold (≥8 mm) that predicts biliary pathology in post-cholecystectomy patients.

## Key findings

- A bile duct diameter of 8 mm or greater is strongly associated with biliary pathology in post-cholecystectomy patients.
- MRCP measurements provided better risk stratification for biliary issues than endoscopic findings.
- Age was an independent predictor of biliary dilatation.

## Abstract

Some patients continue to experience abdominal pain, bloating, or digestive discomfort after gallbladder removal, a condition known as post-cholecystectomy syndrome. Determining whether these symptoms are caused by bile duct problems or by other gastrointestinal conditions can be challenging. In this study, we investigated whether measuring the diameter of the common bile duct using a noninvasive imaging method called magnetic resonance cholangiopancreatography (MRCP) could help identify patients who are more likely to have significant biliary abnormalities. We found that a bile duct diameter of 8 mm or greater was associated with a higher likelihood of underlying biliary pathology. While endoscopy frequently revealed mucosal inflammation, bile duct size provided stronger risk stratification for structural biliary problems. These findings suggest that careful interpretation of MRCP measurements may support a structured and less invasive diagnostic approach, reserving more invasive procedures such as ERCP for selected patients. Further prospective studies are needed to confirm these results.

Background/Objectives: Post-cholecystectomy syndrome (PCS) remains diagnostically challenging due to overlapping biliary and non-biliary causes. This study aimed to evaluate whether common bile duct (CBD) diameter measured by MRCP can serve as a practical triage parameter in symptomatic PCS patients and to define a data-supported threshold for predicting clinically relevant biliary pathology. Secondary objectives included assessing correlations between MRCP findings and upper endoscopic features. Methods: In this retrospective single-center study, symptomatic adults undergoing upper endoscopy and MRCP were analyzed. Demographic, clinical, biochemical, radiologic, and endoscopic variables were recorded. Diagnostic performance was assessed using ROC analysis, and independent predictors of biliary dilatation were evaluated with multivariable logistic regression. Results: We analyzed 141 symptomatic post-cholecystectomy patients (mean age 58.2 ± 16.3 years; 67.4% female; median time since surgery 18 [9–36] months). Major symptoms: abdominal pain 84.9%, dyspepsia/bloating 47.5%, nausea/vomiting 22.3%, diarrhea 15.1%. CBD diameter measurements were available in the MRCP subgroup (n = 45); ERCP was performed selectively (n = 12). MRCP findings: CBD ≥ 7 mm 31.9%, biliary dilatation 14.9%, stricture 2.8%, suspected Oddi dysfunction 11.3%, postoperative complications 39.7%. Endoscopy: mucosal inflammation 91.5%; normal 8.5%. Significant correlations included CBD diameter vs. mucosal inflammation (r = 0.32, p = 0.001), dilatation vs. bile reflux (r = 0.28, p = 0.004), and Oddi dysfunction vs. papillary edema (r = 0.41, p = 0.001). CBD diameter showed the best diagnostic performance (AUC 0.82, 95% CI 0.74–0.90; cut-off ≥ 8.0 mm; sensitivity 78.3%; specificity 81.5%; p < 0.001). In multivariable analysis, age independently predicted biliary dilatation (OR 1.05 per year; 95% CI 1.01–1.09; p = 0.007). Conclusions: In symptomatic post-cholecystectomy patients, MRCP-measured CBD diameter provides a useful metric for risk stratification, with a threshold of ≥8 mm identifying patients more likely to harbor biliary pathology. These findings support a structured diagnostic approach that prioritizes noninvasive imaging while reserving ERCP for selected cases. Further prospective validation is warranted.