From the Guidelines
Persistent biliary ductal dilatation on CT is a significant finding that requires prompt evaluation by a gastroenterologist or hepatobiliary specialist to determine the underlying cause and prevent potential complications. This finding suggests an obstruction in the bile ducts that may be caused by various conditions including gallstones, strictures, tumors (such as cholangiocarcinoma or pancreatic cancer), chronic pancreatitis, or primary sclerosing cholangitis 1. The next step should be additional imaging with magnetic resonance cholangiopancreatography (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP) to better visualize the biliary tree and identify the cause of obstruction.
Key Considerations
- Laboratory tests including liver function tests, bilirubin levels, and tumor markers (CA 19-9, CEA) should be ordered to aid in diagnosis 1.
- If the patient has symptoms such as jaundice, abdominal pain, fever, or weight loss, these should be addressed promptly.
- For symptomatic patients with suspected infection (cholangitis), antibiotics such as piperacillin-tazobactam 3.375g IV every 6 hours or ciprofloxacin 400mg IV twice daily plus metronidazole 500mg IV every 8 hours may be needed.
- Definitive treatment depends on the underlying cause - ERCP with stone extraction for gallstones, stent placement for strictures, or surgical intervention for malignancies.
Diagnostic Approach
- MRCP is noninvasive and highly accurate in diagnosing causes of mechanical CBD obstruction, whereas ERCP is invasive with a 4% to 5% morbidity risk and a 0.4% mortality risk, but is slightly more accurate than MRCP (for choledocholithiasis) and is able to offer the benefit of therapeutic intervention 1.
- Decisions for the next step of imaging should be based on the suspicion for and the patient’s clinical status.
Management
- Biliary dilatation occurs when bile flow is impeded, causing increased pressure in the ducts and subsequent expansion, which is visible on imaging studies.
- Even in asymptomatic patients, persistent biliary dilatation should not be ignored as it may indicate serious underlying pathology.
- The decision to perform endoscopic intervention needs to be individualised and weighed against other treatment options such as liver transplantation 1.
From the Research
Persistent Biliary Ductal Dilatation on CT
- Persistent biliary ductal dilatation on CT can be an incidental finding, and its significance depends on various factors, including the presence of symptoms, laboratory abnormalities, and imaging findings 2, 3.
- The yield of further investigations, such as magnetic resonance cholangiopancreatography (MRCP) or endoscopic ultrasonography (EUS), depends on the degree of dilatation and the presence of symptoms or laboratory abnormalities 3, 4.
- MRCP has been shown to be a valuable tool in the work-up of biliary duct dilatation, with a diagnostic accuracy of 88.9% and a positive predictive value of 94.4% 4.
- EUS is also a reliable modality, especially in patients with extrahepatic biliary obstruction caused by endoluminal sludge, with a diagnostic accuracy of 93.3% and a positive predictive value of 94.7% 4.
Clinical Significance and Management
- The clinical significance of common bile-duct dilatation in patients without biliary symptoms or causative lesions on ultrasonography is uncertain, and further diagnostic study may be helpful for early diagnosis of biliary tract disease 5.
- A significant number of causative biliary tract lesions can be detected in asymptomatic adults with dilatation of the common bile duct on routine abdominal ultrasonography 5.
- The management of biliary duct dilatation depends on various factors, including the presence of symptoms, laboratory abnormalities, and imaging findings, and may involve additional imaging or testing, such as EUS or ERCP 6.
- Consensus recommendations for the management of biliary duct dilatation have been provided in a narrative review, including guidance on interpreting liver function tests, measuring the extrahepatic bile duct, and defining criteria for biliary duct dilatation 6.