CT Angiogram Findings in Budd-Chiari Syndrome

Primary Vascular Findings

Non-visualization or non-opacification of hepatic veins is the hallmark finding, though CT has limitations with false positive and indeterminate results in approximately 50% of cases 1, 2, 4
The hepatic veins may appear as hyperechoic cords replacing normal veins, or show complete absence of normal venous structures 1
A "spider-web" appearance may be visible near the hepatic vein ostia, representing collateral networks 1, 2

Early homogeneous central enhancement, particularly at the caudate lobe level, is pathognomonic 1, 2, 3
Delayed patchy peripheral enhancement with prolonged contrast retention in the liver periphery reflects uneven portal perfusion 1, 2
This heterogeneous enhancement pattern results from compromised portal venous perfusion and compensatory arterial flow 1, 2

Caudate lobe enlargement is found in approximately 75% of patients with Budd-Chiari syndrome 1, 2, 5, 3
This occurs because the caudate lobe has separate venous drainage directly into the IVC through multiple short hepatic veins, allowing outflow sparing and compensatory hypertrophy when other hepatic veins are obstructed 5, 3

Large intrahepatic or subcapsular collateral vessels are present in more than 80% of cases, though CT is less effective than ultrasound in demonstrating these 1, 2, 7
These collaterals connect hepatic veins to diaphragmatic or intercostal veins with continuous flow 1, 2

Macroregenerative nodules that enhance during the arterial phase are common in longstanding Budd-Chiari syndrome 1, 2, 7
These nodules result from intrahepatic portal vein branch obstruction and increased arterial inflow 1, 2, 7

In patients with paroxysmal nocturnal hemoglobinuria (PNH), the CT findings remain the same, but the clinical significance differs as these patients require indefinite anticoagulation and may benefit from eculizumab therapy 6

CT has approximately 50% false positive and indeterminate results when assessing hepatic veins, making it less reliable than Doppler ultrasound for initial diagnosis 1, 2, 4, 8
Iodinated contrast carries renal toxicity risk and radiation exposure is a concern 1, 4, 7
CT may miss small hepatic vein thrombosis when large veins appear patent 4, 7
If CT suggests but does not confirm Budd-Chiari syndrome, Doppler ultrasound by an experienced operator should be used for confirmation and detailed characterization 4, 7, 9, 8
Direct venography is needed for difficult cases and precise delineation before planning interventional treatment 1, 2, 4, 7