Lecture on Liver Sonography

Dr. Oana Baltarowich discusses liver sonography, covering normal liver anatomy, Doppler of the hepatic vessels, diffuse liver disease patterns, portal hypertension, and focal liver masses.

Normal Liver Sonography

• Key Aspects:
  • Size, shape, echogenicity, and echotexture.
  • Echogenicity: Brightness level, compared using portal vein walls.
  • Echotexture: Homogeneity of the liver.
• Technique:
  • Ensure smooth TGC curve and clear margins.
  • Imaged structures should extend 2-3 cm beyond the organ to exclude adjacent masses (e.g., hepatocellular carcinoma).

Echogenicity Relative Scale

• Adrenal medulla: Least echogenic.
• Cortex of kidney: Less or equal to liver echogenicity.
• Liver vs. Spleen: Liver is less echogenic, but not usually visualized together.
• Liver vs. Pancreas: Pancreas usually more echogenic.

Hepatic Vessels

• Portal Veins: Bright echogenic walls due to portal triads (portal vein, hepatic artery, bile duct).
• Hepatic Veins: Typically have imperceptible walls, drain liver to the IVC.
• Anatomic Landmarks:
  • High sections: large hepatic veins.
  • Mid sections: portal veins horizontally situated.

Fetal Remnants

• Ligamentum Teres: Obliterated fetal remnant of the umbilical vein, divides left lobe into medial and lateral segments.
• Ligamentum Venosum: Fetal remnant of the ductus venosus, between caudate lobe and left lobe.

Liver Segmentation

• Hepatic Veins: Dividers between lobes.
• Portal Veins: Used to name segments.
• Couinaud System: Divides liver into 8 segments for surgical precision.

Doppler of Hepatic Vessels

• Portal Vein: Continuous forward flow, low velocity, undulating pattern.
• Hepatic Artery: Rapid systolic acceleration, continuous forward flow.
• Hepatic Veins: Normal triphasic waveform.

Sonographic Liver Patterns

• Centrolobular Pattern: Starry night appearance due to prominent portal vein walls.
• Fatty Fibrotic Pattern: Increased echogenicity, loss of portal vein walls.

Portal Hypertension

• Indications: Aites, dilated main portal vein, splenomegaly.
• Collaterals: Gastroesophageal junction, recanalized umbilical vein, splenorenal shunt.

Liver Masses

• Ultrasound Use: Detects focal liver lesions, specific for liver cysts.
• Cysts: Simple cysts have anechoic nature, complex cysts may contain echoes.
• Solid Masses: Differential includes abscess, adenoma, hemangiomas, metastases.

Conclusion

The lecture covered the various aspects of liver sonography, including anatomy, vessel Doppler patterns, liver disease patterns, portal hypertension, and identification of liver masses.