Choledocholithiasis is the presence of gallstones in the common bile duct (CBD). Usually occurs when gallbladder stones pass through the cystic duct into the CBD (secondary choledocholithiasis). Rarely, stones may form de novo within the CBD (primary choledocholithiasis — pigment stones, more common in Far East). Can lead to serious complications including biliary obstruction, obstructive jaundice, acute cholangitis (Charcot's triad: fever, jaundice, right upper quadrant pain), and acute biliary pancreatitis. MRCP is the gold standard for diagnosis, showing T2 hypointense filling defects in bile ducts. US as primary screening modality shows high sensitivity for detecting CBD dilation but is limited in directly demonstrating distal CBD stones. ERCP is used for both diagnostic and therapeutic (sphincterotomy + stone extraction) purposes.
Age Range
30-80
Peak Age
55
Gender
Female predominant
Prevalence
Common
Choledocholithiasis usually develops through migration of gallbladder stones to the common bile duct via the cystic duct. When the stone impacts at the sphincter of Oddi level, biliary obstruction occurs — intrahepatic bile ducts dilate and conjugated bilirubin enters the blood causing obstructive jaundice. Complete obstruction leads to bile stasis and acute cholangitis may develop with bacterial superinfection (Charcot's triad; Reynolds pentad: Charcot + hypotension + confusion — septic cholangitis). When the stone obstructs the ampulla of Vater, pancreatic duct obstruction may cause acute biliary pancreatitis — preactivation of pancreatic enzymes leads to parenchymal autodigestion. On MRCP, stones appear as T2 hypointense filling defects because solid crystalline structure contains no free water and creates marked contrast with surrounding T2 hyperintense bile fluid — bile remaining around the stone is described as 'meniscus sign'. CBD dilation (>6-7 mm) on US is an indirect indicator of obstruction. Stone composition affects diagnostic performance: cholesterol stones can be isodense-hypodense on CT (reducing CT sensitivity), while pigment and calcium stones appear hyperdense.
Crescent-shaped appearance of hyperintense bile fluid remaining around/above the stone in the CBD lumen on MRCP. Stone is hypointense (dark), surrounding bile hyperintense (bright), creating pathognomonic contrast. The most characteristic finding of MRCP for choledocholithiasis diagnosis, clearly distinguishing from mass/stricture in cholangiocarcinoma.
T2 hypointense (dark) filling defect within the CBD lumen on MRCP — stone. High-signal bile fluid remaining above and/or around the stone appears as a crescent shape — 'meniscus sign'. Stones may be round, oval, or faceted and may be multiple. Small stones (<5 mm) may be missed on 2D MRCP — sensitivity increases with 3D MRCP thin sections (≤1 mm). MRCP shows 90-98% sensitivity and 95-100% specificity for choledocholithiasis diagnosis.
Report Sentence
A T2 hypointense filling defect within the CBD lumen is identified on MRCP, consistent with choledocholithiasis; surrounding bile fluid forms a meniscus sign.
CBD dilation (>6-7 mm; >10 mm post-cholecystectomy) on US is the primary screening finding for choledocholithiasis. Dilated CBD is seen as an anechoic tubular structure coursing anterior to the portal vein. Stones in the proximal CBD may appear as echogenic foci + acoustic shadow, but stones in the distal CBD (pancreatic segment) may not be directly visible due to duodenal gas artifact. US sensitivity for CBD dilation is 80-95%, for stone detection 50-80%.
Report Sentence
CBD dilation (diameter: ... mm) is identified, suggesting obstructive pathology; further evaluation with MRCP for choledocholithiasis is recommended.
Hyperdense round/oval structure in the CBD lumen on non-contrast CT — calcified gallstone. CT stone detection sensitivity depends on stone composition: calcified (pigment) stones are markedly hyperdense (>100 HU), mixed stones intermediate density, pure cholesterol stones are isodense or hypodense and may not be detectable on CT. Therefore CT's overall sensitivity is 70-85% and lower than MRCP. However, CT is highly specific for calcified stones.
Report Sentence
A hyperdense structure in the CBD lumen on non-contrast CT is identified, consistent with choledocholithiasis (calcified gallstone).
CBD wall thickening and enhancement ('target sign') on contrast-enhanced CT in choledocholithiasis with acute cholangitis. Inflammation causes CBD wall edema and hyperemia. Stone may be visible within the lumen as hyperdense or isodense. Periportal edema (periportal tracking) may accompany as hypointense halos around the hepatic hilum. These findings suggest acute cholangitis superinfection.
Report Sentence
CBD wall enhancement and thickening is identified, consistent with acute cholangitis secondary to choledocholithiasis.
Echogenic focus with distal acoustic shadow within the CBD lumen on US — direct demonstration of gallstone. This finding is more easily detected in proximal CBD; sensitivity is lower in distal CBD due to duodenal gas interference. Stone may change position — repeated examination in supine and left lateral decubitus positions increases sensitivity. Multiple stones may appear as aligned echogenic foci.
Report Sentence
An echogenic focus with acoustic shadow within the CBD lumen is identified, consistent with choledocholithiasis.
Low-signal filling defect within the dilated CBD lumen on T2-weighted sequences. Stone is distinctly separated from surrounding high-signal bile. T2 sequences show better anatomic detail than MRCP and allow evaluation of relationship with surrounding structures (portal vein, pancreas). Air bubbles (post-sphincterotomy), blood clot, and tumor can also create T2 hypointense filling defects — clinical correlation required.
Report Sentence
A low-signal filling defect within the dilated CBD lumen on T2-weighted sequences is identified, consistent with choledocholithiasis.
Criteria
Stone migrating from gallbladder to CBD via cystic duct. Most common type (80-90%). Usually cholesterol or mixed stones. Accompanying gallbladder stones common.
Distinct Features
Accompanying gallbladder stones support if no cholecystectomy history. Stone usually proportional to CBD caliber (small-medium). Cholecystectomy + ERCP is standard treatment.
Criteria
Stone forming de novo within CBD. Less common. Usually pigment (calcium bilirubinate) stones. More common in Far East. Bile stasis, bacterial infection, and biliary anomalies predispose.
Distinct Features
Can develop after cholecystectomy (no gallbladder stone source). Stones usually soft, brown pigment stones. Intrahepatic stones may accompany (recurrent pyogenic cholangitis). Usually hyperdense on CT (calcium content).
Criteria
Stone impacted at the sphincter of Oddi level. Highest risk for complete biliary obstruction and acute cholangitis/pancreatitis. May create double duct sign.
Distinct Features
Emergency ERCP indication (especially if cholangitis or pancreatitis accompanies). T2 hypointense filling defect at ampullary region on MRCP. Double duct sign supports ampullary obstruction. Spontaneous passage possible but intervention recommended before serious complications.
Distinguishing Feature
In distal cholangiocarcinoma, enhancing periductal mass and delayed enhancement; stricture on MRCP (no meniscus sign). In choledocholithiasis, stone as T2 hypointense filling defect with meniscus sign; no enhancing mass.
Distinguishing Feature
In pancreatic head carcinoma, hypodense mass in pancreatic parenchyma externally compresses CBD. In choledocholithiasis, pancreatic parenchyma is normal, filling defect within CBD lumen.
Distinguishing Feature
In Mirizzi syndrome, stone is impacted in cystic duct or gallbladder neck externally compressing common hepatic duct. In choledocholithiasis, stone is within CBD lumen. Stone localization (cystic duct vs CBD) on MRCP is differentiating.
Distinguishing Feature
Acute cholangitis is usually a complication of choledocholithiasis — both may coexist. In acute cholangitis, CBD wall enhancement, periportal edema, and septic clinical picture (Charcot's triad) are added. In isolated choledocholithiasis, CBD wall inflammation may be minimal.
Urgency
urgentManagement
interventionalBiopsy
Not NeededFollow-up
specialist-referralTreatment of choledocholithiasis is ERCP with sphincterotomy and stone extraction (balloon or basket). Emergency ERCP is indicated if acute cholangitis accompanies (within 24-48 hours). Cholecystectomy is also planned if gallbladder stones are present (usually laparoscopic, after or concurrent with ERCP). Large stones (>15 mm) may require mechanical lithotripsy or surgical exploration. Early ERCP (24-72 hours) is recommended if acute biliary pancreatitis accompanies. Small incidentally detected CBD stones may pass spontaneously but treatment is generally recommended due to complication risk.
Choledocholithiasis causes biliary colic, obstructive jaundice, acute cholangitis, and biliary pancreatitis. Treated with ERCP (sphincterotomy + stone extraction). MRCP is the gold standard imaging for preoperative diagnosis.