## Gold Standard for Choledocholithiasis Detection **Key Point:** MRCP is the non-invasive imaging modality of choice for detecting choledocholithiasis and defining the biliary tree anatomy in obstructive jaundice. ### Why MRCP is Preferred **High-Yield:** MRCP offers: - High sensitivity (95–98%) and specificity (95–100%) for detecting stones in the common bile duct - Non-invasive with no radiation exposure - Excellent visualization of the entire biliary tree and pancreatic ductal system - No risk of iatrogenic pancreatitis (unlike ERCP) - Can be performed safely even in patients with coagulopathy or altered anatomy ### Role of Other Modalities | Modality | Sensitivity for CBD stones | Role in Workup | Limitation | | --- | --- | --- | --- | | Ultrasonography | 50–65% | Initial screening | Poor visualization of distal CBD | | MRCP | 95–98% | Diagnostic imaging (gold standard) | Requires expertise; longer acquisition time | | ERCP | ~95% | Therapeutic (stone extraction) | Invasive; risk of pancreatitis (3–7%) | | CT | 70–85% | Staging; assessing complications | Less sensitive than MRCP for small stones | **Clinical Pearl:** ERCP is reserved for therapeutic intervention (sphincterotomy and stone extraction) rather than diagnosis alone, as it carries a 3–7% risk of post-ERCP pancreatitis. **Tip:** In the NEET PG exam, remember: MRCP = diagnostic gold standard; ERCP = therapeutic gold standard. 
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