• Fasting Requirements: You must fast (abstain from all solid foods and liquids except plain water) for at least 6 to 8 hours before your appointment. This is the most critical preparation step: fasting reduces gas pockets in your intestines, which can completely block ultrasound waves from reaching the deep liver vessels.
• Medications: You may take your regular medications with small sips of plain water on the morning of the scan.
• Clothing: Wear loose, comfortable clothing. You will likely be asked to change into a medical gown so the clinical team can easily access your entire upper abdomen.

During the scan, the radiologist calculates precise structural and dynamic metrics across the axis:

Key parameters assessed during the scan include:

• Vessel Diameter: Measuring the width of the portal and splenic veins, as widening often points to high pressure.
• Direction of Flow: Confirming whether the blood is moving toward the liver (hepatopetal, which is healthy) or flowing backward away from the liver (hepatofugal, which indicates severe portal hypertension).
• Flow Velocity: Tracking the speed and natural wave patterns of the blood to ensure the liver is receiving adequate circulation.
• Spleen Size: Checking for an enlarged spleen (splenomegaly), which frequently occurs when blood backs up into the splenic vein.