Liver Ultrasound – Anatomy, Technique & Interpretation

Learning Objectives

By the end of this session, learners will be able to:

• Understand liver anatomy relevant to ultrasound
• Perform standard liver ultrasound scans
• Identify normal and pathological liver findings
• Apply Doppler techniques for vascular assessment

1. Introduction to Liver Ultrasound

• Non-invasive imaging modality using high-frequency sound waves
• Commonly used for evaluating liver size, texture, lesions, and vascular flow
• Indications: abdominal pain, abnormal liver function tests, suspected masses, cirrhosis, portal hypertension

2. Liver Anatomy Overview

• Lobes: Right, Left, Caudate, Quadrate
• Segments: Based on Couinaud classification (I–VIII)
• Vascular landmarks:
  • Portal vein (echogenic walls, horizontal course)
  • Hepatic veins (non-echogenic walls, vertical course)
  • Hepatic artery and bile ducts (in portal triad)

3. Scanning Technique

• Patient Prep: Fasting 6–8 hours to reduce bowel gas
• Positioning: Supine, left lateral decubitus
• Probe: Curvilinear transducer (3–5 MHz)
• Approaches:
  • Subcostal
  • Intercostal
  • Epigastric
• Views:
  • Longitudinal and transverse of right and left lobes
  • Visualization of diaphragm, gallbladder, and adjacent organs

4. Normal Liver Appearance

• Homogeneous echotexture
• Smooth contour
• Size: Right lobe ≤15 cm in midclavicular line
• Portal vein diameter ≤13 mm
• Hepatic veins show triphasic flow on Doppler

5. Pathological Findings

• Fatty Liver: Increased echogenicity, obscured vessels
• Cirrhosis: Nodular surface, coarse texture, small size
• Masses: Hypoechoic (e.g., metastases), hyperechoic (e.g., hemangiomas)
• Cysts: Anechoic with posterior enhancement
• Abscesses: Complex with debris and septations
• Portal Hypertension: Enlarged portal vein, splenomegaly, collaterals

6. Doppler Assessment

• Portal Vein: Hepatopetal flow, monophasic
• Hepatic Veins: Triphasic waveform
• Hepatic Artery: Low resistance flow
• Abnormalities: Reversed flow, thrombosis, shunts

7. Case Studies & Image Review

• Interactive review of normal and abnormal liver ultrasound images
• Discussion of diagnostic approach and differential diagnosis

8. Summary & Takeaways

• Liver ultrasound is essential for evaluating hepatic structure and function
• Mastery of scanning technique and anatomy improves diagnostic accuracy
• Doppler adds valuable vascular insights