Introduction: 
Percutaneous liver biopsy is a vital procedure for diagnosing focal and diffuse liver diseases in children. The vast majority of biopsies can be performed with sonographic guidance only. Given the technical limitations of transjugular biopsies in children, percutaneous biopsy remains the procedure of choice, with correction of coagulopathy or drainage of ascites prior to the biopsy. 

Indications:

• Diagnosis of diffuse liver disease. 
• Evaluation of focal liver lesions. 
• Assessment of unexplained liver dysfunction. 
• Follow-up for known liver conditions. 

Contraindications:

• Uncorrectable coagulopathy. 
• Severe ascites. 
• Unfavorable anatomy, with increased complication risks. 
• Respiratory instability or severe chronic lung disease complicating positioning and biopsy performance. 

Equipment:

 1. Biopsy Needles: 

• 16- and 18-gauge Easy Core (Boston Scientific). 
• 16-, 18-, and 20-gauge Adjustable Coaxial Temno or Temno Evolution (Cardinal Health). 
• 16-gauge Biopince (Angiotech). 
• 16-gauge Magnum Disposable Core Needle (CR Bard).

2. Imaging Equipment:

• High-resolution ultrasound or CT scanner for real-time guidance. 

3. Local Anesthesia:

• Lidocaine for infiltration. 

4. Coaxial Biopsy System (if multiple biopsies are required): 

• Guiding outer needle and coaxial needle for sample collection. 

5. Hemostatic Material: 

• Absorbable gelatin foam (Gelfoam, Pfizer) or microfibrillar collagen (Avitene, Medchem Products) slurry for tract embolization to minimize bleeding risks. 

Pre-Procedure Workup:

1. Clinical Review: 

• Evaluate clinical indications and coagulation status. 
• Obtain informed consent from parents or guardians. 

​2. Coagulation Profile: 

• Correct abnormal coagulation profiles per SIR guidelines (INR < 1.5, platelets > 50,000/mm³). 

3. Anesthesia: 

• Sedation administered by the anesthesiologist. Tracheal intubation may be required for patients with severe respiratory compromise or aspiration risk. 

4. Sonogram: 

• Utilize highest frequency probe that allows evaluation of liver and peritoneal cavity. Most commonly linear 9-11 or curved 5 MHz. Obtain images from all quadrants and pelvis, and document ascites pre-biopsy. 

Technique:

1. Approach: 

• Right lobe: Preferrably subcostal. Intercostal only if no other safe access. 
• Left lobe: Subxiphoid. 

2. Preparation: 

• Perform the procedure during expiration to stabilize the liver. 
• Determine the shortest and safest trajectory for focal lesions. 

3. Techniques: 

• Free-hand sonography. 
• Infiltrate local anesthetic under sonographic guidance. 
• Coaxial technique and number of liver capsule passes decided by the performing pediatric interventional radiologist. ​

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Left image shows a 16-guage Temno biopsy needle deployed through 15G coaxial into the anterior left lobe of the liver under sonography. Right image shows embolized biopsy tract. ​

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4. Steps: 

• Infiltrate skin and subcutaneous tissue with 1% lidocaine (max 0.5 mL/kg). Perform under sonographic guidance to confirm trajectory. 
• Make a small incision with a #11 scalpel. 
• For diffuse disease, access peripheral parenchyma distant from portal triad. 
• Always use coaxial technique. 
• Introduce the coaxial needle under direct sonographic guidance, minimizing the time taken to traverse the liver capsule. Steepen trajectory to ease puncture of liver capsule and then flatten needle. 
• Try to only puncture the liver capsule once. 
• If using semi-automated system, advance the needle and then compress tissue into the specimen well. 
• One 16G core will suffice for rejection, 2 cores for other diffuse disease. The number of samples required for focal lesions depends on the presumed diagnosis. 
• If persistent bleeding from coaxial needle, first try to embolize with autologous clot. If unsuccessful, then embolize with pledget or slurry.  
• Conduct post-procedural ultrasound to detect complications. 

5. Tract Embolization (if needed): 

• Use absorbable gelatin foam (Gelfoam) or microfibrillar collagen (Avitene) slurry for cases requiring multiple cores (4+). 

​
Post-Procedure Care:

1. Observation: 

• Monitor in the recovery room for at least 2 hours (one hour flat, one reclined) 
• Check vital signs (pulse, BP, respiratory rate). 

2. Hematocrit Monitoring: 

• Repeat hematocrit 4 hours post-procedure only if concern for bleeding. 
• If a drop >5 percentage points is noted, perform a limited ultrasound to assess for intraperitoneal bleeding. 
• Admit for overnight observation if free fluid is detected. 

3. Discharge: 

• If no complications are observed, discharge the patient with instructions provided to family or guardians. 
• Inpatients are transferred back to their floor after recovery room observation. 

Complications:

• Bleeding from the biopsy site or within the liver. 
• Pneumothorax from inadvertent pleural space entry. 
• Referred right shoulder pain. 
• Dislodgment of embolization material. 
• Rare cases of infection. 

References:

1. Hoffer FA. Liver biopsy methods for pediatric oncology patients. Pediatr Radiol. 2000;30(7):481. 
2. Kaye RD, Towbin RB. Imaging and intervention in the gastrointestinal tract in children. Gastroenterol Clin North Am. 2002;31(3):897–923. 
3. Riddle C, Ahmed B, Doyle J, Connolly BL. Migration of Gelfoam to the gallbladder after liver biopsy. Pediatr Radiol. 2008;38(7):806–9. 
4. Malloy PC, et al. Consensus guidelines for coagulation management in percutaneous interventions. J Vasc Interv Radiol. 2009;20(7 Suppl):S240–S249. 
5. Mason KP, et al. Radiologist-supervised ketamine sedation for pediatric biopsies. AJR. 2009;192:1261–1265. 
6. Govender P, et al. Sonography-guided liver biopsies in children. AJR Am J Roentgenol. 2013;201(3):645-650. doi:10.2214/AJR.12.9802.