Obstruction of hepatic venous outflow: absent or reversed flow in the hepatic veins, intrahepatic comma-shaped collaterals, a hypertrophied caudate lobe and a mosaic enhancement pattern — find the level (veins, IVC web) for the interventional plan.
Orient first
- Primary Budd–Chiari: thrombosis or membranous web of the hepatic veins or IVC; secondary: tumour compression or invasion.
- The caudate lobe drains directly into the IVC and hypertrophies.
- Acute: large tender liver with ascites; chronic: regenerative nodules that mimic tumours.
Acquire the study
- Curvilinear probe with colour and spectral Doppler of all three hepatic veins and the IVC; low PRF for slow flow.
The manoeuvre
- Colour Doppler: absent, reversed or turbulent flow in each hepatic vein.
- Spectral Doppler: loss of the normal triphasic waveform in the hepatic veins; flat or reversed flow.
- Intrahepatic comma-shaped collaterals; a caudate vein > 3 mm (verify).
- IVC web or thrombus at the diaphragm.
What confirms it
- Absent or obstructed hepatic venous outflow with compatible parenchymal changes.
What licenses you to exclude it
- Patent hepatic veins with a normal triphasic waveform and a patent IVC exclude Budd–Chiari.
The classic misread
- A monophasic hepatic vein waveform alone is non-specific (cirrhosis, pregnancy).