Indications for Liver Ultrasound

Liver ultrasound is commonly utilized in the evaluation of various hepatic conditions. The most frequent indications include:

• 1. Monitoring chronic liver disease
• 2. Hepatocellular Carcinoma (HCC) Surveillance
• 3. Evaluation of Jaundice
• 4. Guidance for Interventional Procedures
• 5. Doppler Evaluation of Hepatic and Portal Circulation
• 6. Right Upper Quadrant (RUQ) Pain
• 7. Pre- and Post-Liver Transplant Evaluation
• 8. Hepatomegaly or Splenomegaly
• 9. Suspected Liver Infection
• 10. Fatty Liver Disease (Hepatic Steatosis)
• 11. Detection and Evaluation of Liver Masses
• 12. Abnormal Liver Function Tests

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1. Monitoring Chronic Liver Disease

Chronic liver disease refers to progressive deterioration of liver function over time, typically due to long-term inflammation, fibrosis, and eventual cirrhosis. Common causes include viral hepatitis (B and C), alcohol-related liver disease, non-alcoholic fatty liver disease (NAFLD), autoimmune hepatitis, and genetic/metabolic disorders.

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Goals of Monitoring

• Assess disease progression
• Identify complications early
• Evaluate response to treatment
• Detect hepatocellular carcinoma (HCC) early
• Determine timing for interventions (e.g., transplant referral)

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1. Clinical Assessment

Evaluation of symptoms: fatigue, jaundice, ascites, encephalopathy, GI bleeding.
Physical exam: hepatomegaly, splenomegaly, spider angiomas, edema, asterixis.

2. Laboratory Monitoring

• Liver Function Tests (LFTs): ALT, AST, ALP, GGT, bilirubin
• Synthetic Function: Albumin, INR/PT
• Complete Blood Count (CBC): Thrombocytopenia may indicate portal hypertension
• Renal Function: Important in advanced liver disease (e.g., hepatorenal syndrome)
• Alpha-fetoprotein (AFP): For HCC surveillance

3. Imaging Surveillance

• Ultrasound (every 6 months): Monitoring liver morphology, ascites, HCC screening
• Elastography (FibroScan): For fibrosis assessment
• CT or MRI: When ultrasound is inconclusive

4. Endoscopy

Upper GI endoscopy: To screen for esophageal varices in cirrhotics

5. Lifestyle and Comorbidity Management

• Alcohol cessation, weight loss, diabetes control
• Vaccinations: Hepatitis A and B, pneumococcus, influenza
• Nutritional support and vitamin supplementation

6. Treatment Response

• Viral load monitoring in hepatitis B/C
• ALT normalization in NAFLD after lifestyle changes

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Complication Surveillance

• Ascites: Detected by exam and ultrasound. Perform paracentesis if needed.
• SBP: Suspect with worsening ascites. PMN ≥250/mm³ diagnostic.
• Hepatic Encephalopathy: Assessed clinically. Serum ammonia may help.
• HCC: Screen every 6 months with ultrasound ± AFP in high-risk patients.

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Frequency of Follow-Up

• Compensated cirrhosis: Follow-up every 6–12 months
• Decompensated cirrhosis: Every 1–3 months
• High-risk HCC patients: Liver ultrasound every 6 months

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2. Hepatocellular Carcinoma (HCC) Surveillance

HCC is the most common primary liver cancer, often arising in chronic liver disease. Surveillance aims to detect cancer early in high-risk patients.

Rationale

• Early-stage HCC is asymptomatic and treatable.
• Surveillance allows curative treatment: surgery, transplantation, or ablation.
• Improves survival by enabling early detection.

High-Risk Groups

• All cirrhotic patients
• Chronic hepatitis B (even without cirrhosis in certain demographics)
• Chronic hepatitis C with fibrosis or cirrhosis
• NASH with cirrhosis
• Autoimmune hepatitis, PBC, hemochromatosis with cirrhosis

Surveillance Approach

• Ultrasound every 6 months
• ± Serum AFP for enhanced sensitivity
• CT/MRI for poor ultrasound window or indeterminate lesions

Limitations

• Operator- and patient-dependent sensitivity
• Reduced detection for small/infiltrative tumors
• AFP is non-specific

Management of Findings

• Lesions ≥1 cm → CT/MRI evaluation
• < 1 cm → repeat US in 3 months
• Typical imaging may obviate biopsy

3. Evaluation of Jaundice

• Distinguish intrahepatic vs extrahepatic causes.
• Intrahepatic: altered liver texture, cirrhosis, hepatitis.
• Extrahepatic: bile duct dilatation from stones, strictures, or masses.
• Measure CBD diameter, assess for obstruction.
• Guide MRCP/ERCP when needed.

4. Guidance for Interventional Procedures

• Liver Biopsy: Real-time needle guidance
• Abscess Drainage: Ensures accurate catheter placement
• Cyst/Tumor Aspiration: Supports FNA procedures
• Tumor Ablation: RFA/MWA requires precise targeting
• Portal Vein Access: Used in TIPS procedures

5. Doppler Evaluation of Hepatic and Portal Circulation

• Blood Flow Assessment: Hepatic artery, portal vein, hepatic veins
• Portal Hypertension: Reduced portal velocity, reversal of flow, varices
• Portal Vein Thrombosis: Detect absence or reduced flow
• Budd–Chiari Syndrome: Identify hepatic vein/IVC obstruction
• Transplant Evaluation: Monitor vascular patency pre- and post-op

6. Right Upper Quadrant (RUQ) Pain

• First-line assessment: Gallbladder, liver, bile ducts, and kidney.
• Gallbladder: Detects stones, wall thickening, pericholecystic fluid, Murphy's sign.
• Liver causes: Abscesses, cysts, tumors, or hepatomegaly.
• Biliary tree: Checks for intra- and extrahepatic duct dilation.
• Kidney: Identifies hydronephrosis or stones mimicking RUQ pain.

7. Pre‑ and Post‑Liver Transplant Evaluation

• Pre‑transplant: Evaluate liver morphology, detect HCC or thrombosis, check vascular anatomy.
• Vascular mapping: Doppler of hepatic artery, portal vein, and hepatic veins.
• Immediate post‑transplant: Monitor graft perfusion and detect early complications.
• Hepatic artery complications: Detect thrombosis or stenosis via resistance index and flow patterns.
• Portal/hepatic vein evaluation: Identify thrombosis or stenosis affecting graft function.
• Long-term: Follow graft health, biliary complications, rejection, or recurrence.

8. Hepatomegaly or Splenomegaly

• Hepatomegaly: Measures liver size, contour, echotexture, and detects masses.
• Texture changes: Bright liver = steatosis; coarse = fibrosis or cirrhosis; focal lesions indicate masses.
• Splenomegaly: Quantifies spleen size; checks texture; may reflect portal hypertension, hematologic issues, or infection.
• Portal assessment: Doppler evaluation of portal vein, flow direction, and signs of collaterals or hypertension.
• Monitoring: Serial ultrasound tracks changes post-treatment or in disease progression.

9. Suspected Liver Infection

• Infections include: Pyogenic or amoebic abscesses, hepatitis, fungal involvement.
• Ultrasound: Shows hypoechoic or complex lesions in abscesses; diffuse enlargement in hepatitis.
• Intervention: Guides abscess aspiration or drainage and specimen collection.
• Doppler: Checks for vascular invasion or thrombosis in and around lesion.
• Follow-up: Monitors treatment response and resolution or progression.

10. Fatty Liver Disease (Hepatic Steatosis)

• Definition: Accumulation of fat causes increased echogenicity of the liver.
• Appearance: Brighter liver and difficult vessel/diaphragm visualization in advanced cases.
• Significance: Tied to obesity, diabetes, metabolic syndrome, and alcohol use; may progress to NASH or cirrhosis.
• Ultrasound role: Screens and monitors fat accumulation.
• Limitations: Cannot quantify fat or differentiate simple vs NASH accurately.

11. Detection and Evaluation of Liver Masses

• Mass types: Benign (hemangiomas, focal nodular hyperplasia, cysts) and malignant (HCC, metastases).
• Ultrasound features: Cysts = anechoic; hemangiomas = hyperechoic; malignant = heterogeneous, irregular, vascular.
• Doppler: Assesses vascular patterns to differentiate lesions.
• Further imaging: CT/MRI recommended for lesions >1 cm or unclear.
• Biopsy guidance: Employed for histological confirmation if needed.

12. Abnormal Liver Function Tests (LFTs)

• Persistent LFT elevation: Ultrasound evaluates structural causes—steatosis, fibrosis, masses, bile duct dilation.
• Assess complications: Detects ascites, splenomegaly, posthepatic obstruction.
• Follow-up: Helps monitor disease progression or therapeutic response.

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