Introduction to Liver Ultrasound
Purpose and Clinical Relevance
Purpose:
Liver ultrasound is a non-invasive, cost-effective, and widely accessible imaging modality used to evaluate the liver's structure and detect abnormalities. It is often the first-line imaging technique for assessing liver disease due to its safety (no radiation), real-time capability, and ability to guide interventional procedures.
Clinical Relevance:
- Early Detection of Liver Disease: Identifies early signs of fatty liver, hepatomegaly, or focal lesions.
- Assessment of Liver Size, Shape, and Texture: Helps evaluate hepatomegaly, atrophy, or nodular surface changes.
- Characterization of Liver Lesions: Differentiates benign (e.g., hemangioma, cysts) from malignant lesions (e.g., HCC, metastases).
- Monitoring Chronic Liver Disease: Tracks progression in hepatitis, NAFLD, and fibrosis.
- Guidance for Interventional Procedures: Real-time guidance for biopsies, drainages, and aspirations.
- Evaluation of Vascular and Biliary Systems: Assesses portal vein, hepatic veins, and biliary duct dilation.
- Surveillance in High-Risk Populations: Routine use for cirrhosis, chronic hepatitis B/C.
- Screening in Asymptomatic Patients: Detects incidental findings of early liver disease.
Indications for Liver Ultrasound
- Evaluation of Abnormal LFTs
- Elevated ALT, AST, ALP, bilirubin
- Unexplained enzyme abnormalities
- Assessment of Liver Size and Texture
- Suspected hepatomegaly or atrophy
- Palpable liver
- Characterization of Lesions
- Cysts, hemangiomas, adenomas
- Primary/metastatic tumors
- Cancer Surveillance
- Cirrhosis
- Chronic hepatitis B/C
- NASH
- Chronic Liver Disease
- NAFLD, alcoholic liver disease
- Fibrosis or cirrhosis
- Portal Hypertension
- Splenomegaly, ascites, varices
- Doppler of portal vein
- Biliary Obstruction
- Jaundice, RUQ pain
- Elevated ALP, GGT
- Gallstones, bile duct dilatation
- Guided Procedures
- Biopsy, drainage, aspiration
- Follow-up Studies
- Monitoring known lesions
- Treatment response (e.g., ablation)
- Infectious or Inflammatory Causes
- Pyogenic/amebic abscess
- Hepatitis (viral or autoimmune)
- Pediatric Liver Conditions
- Neonatal cholestasis
- Congenital anomalies
- Metabolic liver disease
Limitations and Contraindications
Limitations:
- Operator dependence
- Small/isoechoic lesions may be missed
- Obesity, gas, or ascites may impair view
- Difficulty distinguishing benign vs malignant lesions
- Limited field of view (deep dome lesions)
- No functional assessment (e.g., perfusion)
- Incomplete view of biliary tree
Contraindications:
- Recent surgery or trauma (pain, dressings)
- Non-cooperative patients (infants, confused)
- Excessive abdominal distension (gas, ascites)
