Liver Ultrasound Findings in Budd-Chiari Syndrome
In a patient with Budd-Chiari syndrome, liver ultrasound with Doppler will show specific hepatic vein abnormalities including absent or reversed flow, intrahepatic collaterals (present in >80% of cases), and caudate lobe hypertrophy (present in ~75% of cases). 1
Primary Doppler Ultrasound Features
Doppler ultrasound by an experienced operator is the first-line diagnostic test for Budd-Chiari syndrome, with diagnostic sensitivity exceeding 75%. 2, 1 The following features are considered specific for hepatic vein obstruction:
Hepatic Vein Abnormalities
- Large hepatic veins with absent flow signal, reversed flow, or turbulent flow 1
- Absent or flat hepatic vein waveform without normal respiratory phasicity 1
- Hyperechoic cord replacing a normal vein (representing chronic thrombosis) 1
- Spider-web appearance near hepatic vein ostia with absence of normal hepatic veins in that area 1
Collateral Circulation
- Large intrahepatic or subcapsular collaterals with continuous flow connecting hepatic veins to diaphragmatic or intercostal veins—this finding is present in more than 80% of cases and is highly distinctive for BCS 1, 2
- These collaterals differentiate BCS from other causes of hepatic vein abnormalities such as cirrhosis 1
Morphologic Changes
- Caudate lobe hypertrophy occurs in approximately 75% of patients due to separate venous drainage directly into the IVC, allowing compensatory enlargement 1, 3
- Hepatomegaly with altered liver contour 4
- Narrowing of the intrahepatic IVC related to caudate lobe enlargement 1
Gray-Scale Ultrasound Findings
- Absence of visualization or tortuosity of hepatic veins on real-time imaging, though this is not specific and can occur in advanced cirrhosis 1, 2
- Heterogeneous liver parenchyma with areas of varying echogenicity 5
- In acute cases, at least one hepatic vein will show stenosis, dilatation, thick wall echoes, thrombosis, or abnormal course 5
- In chronic cases, hepatic veins may not be visible at all 5
Additional Findings in Longstanding Disease
- Macroregenerative nodules that enhance during arterial phase imaging—these are common in chronic BCS and can simulate hepatocellular carcinoma 1, 6
- Ascites is a common clinical finding that may be visible on ultrasound 4
Context for PNH Patients
In your patient with paroxysmal nocturnal hemoglobinuria (PNH) and hepatic vein thrombosis, the ultrasound findings would be identical to those described above. PNH is a well-recognized thrombophilic condition associated with Budd-Chiari syndrome, and these patients have high risk for progressive thrombosis despite anticoagulation. 4, 7, 8 The ultrasound should be performed by an experienced operator aware of the clinical suspicion to maximize diagnostic yield 1, 2.
Important Caveats
- Operator experience is critical—the diagnostic yield depends heavily on the examiner's awareness of BCS and technical expertise 1, 2
- Patient body habitus may limit the study quality 1
- Failure to detect IVC thrombosis can occur with ultrasound alone—two caval thromboses were missed in one series 5
- If ultrasound findings are equivocal or non-diagnostic, MRI with contrast or direct venography should be performed for definitive diagnosis 1, 2