The "Double Duct" Sign Nuances

Simultaneous dilatation of both the common bile duct (CBD) and the main pancreatic duct (MPD) strongly suggests an obstructing lesion in the pancreatic head or ampulla.

• Malignant Stricture: Look for an abrupt, blunt, or irregular cutoff of the dilated ducts. This morphological "shelf" points heavily toward pancreatic head adenocarcinoma, ampullary carcinoma, or distal cholangiocarcinoma.

• Benign Stricture: A smooth, gradually tapering stricture ("bird's beak") is more indicative of a benign inflammatory process, such as chronic pancreatitis or an impacted gallstone, though malignancy must always be completely excluded.