Radiology · Year 4 · from Radiology

Case 3: CT-Guided Lung Biopsy

Patient Demographics

  • Age: 67 years
  • Sex: Female

Chief Complaint

Incidental pulmonary nodule found on CT

Presenting Symptoms

The patient underwent CT of the abdomen for evaluation of abdominal pain (ultimately diagnosed as diverticulitis, now resolved). The CT incidentally demonstrated a lung nodule at the lung bases. She is asymptomatic from a pulmonary standpoint with no cough, hemoptysis, dyspnea, or weight loss. She has a 35 pack-year smoking history and quit 5 years ago.

Physical Exam Findings

  • Vital Signs: Within normal limits
  • General: Well-appearing, no distress
  • Pulmonary: Clear to auscultation bilaterally, no wheezes or crackles
  • Lymph Nodes: No cervical or supraclavicular lymphadenopathy
  • No Clubbing

Imaging Findings and Interpretation

Chest CT (Dedicated):

  • Nodule Characteristics:
  • Location: Right lower lobe, peripheral
  • Size: 2.2 x 1.8 cm
  • Morphology: Spiculated margins with pleural tail
  • Density: Solid, no calcification
  • No cavitation
  • Lung-RADS Category: 4B (>15mm solid nodule with suspicious features)
  • Probability of Malignancy: >15% based on size, morphology, and smoking history
  • Mediastinum: No enlarged lymph nodes (all <1cm short axis)
  • Other Findings: Mild centrilobular emphysema

PET-CT:

  • Nodule demonstrates FDG avidity with SUVmax 6.8
  • No FDG-avid mediastinal or hilar lymph nodes
  • No evidence of distant metastatic disease

Risk Assessment: Using the Brock Model (lung cancer prediction): Estimated probability of malignancy >40% given size, spiculation, smoking history, and FDG avidity.

Interventional Radiology Procedure

CT-Guided Percutaneous Lung Biopsy:

Pre-Procedure Planning:

  • Review of CT for optimal approach
  • Shortest path to lesion avoiding fissures and major vessels
  • Patient positioned prone for posterior approach
  • INR 1.1, platelets 245,000 (adequate)
  • Informed consent obtained discussing pneumothorax and hemorrhage risk

Procedure:

  • CT guidance used for real-time needle localization
  • Local anesthesia with 1% lidocaine
  • Coaxial technique: 19-gauge introducer needle advanced to lesion margin
  • Position confirmed on CT
  • 20-gauge core biopsy needle through introducer
  • 4 core samples obtained
  • Samples submitted for histology and molecular testing
  • Post-biopsy CT: Small pneumothorax (~10%), no intervention required

Immediate Post-Procedure:

  • Positioned biopsy side down
  • Monitored in recovery for 2 hours
  • Repeat CXR at 2 hours: Stable small pneumothorax
  • Discharged with instructions for pneumothorax precautions

Pathology Results

  • Histology: Non-small cell lung carcinoma, adenocarcinoma subtype
  • Molecular Testing:
  • EGFR: Wild type
  • ALK: Negative
  • ROS1: Negative
  • PD-L1: 60% (high expression)
  • KRAS: G12C mutation positive

Diagnosis

Stage IA2 non-small cell lung cancer (adenocarcinoma), KRAS G12C mutant, PD-L1 high

Management

  1. Staging Workup:
  • Brain MRI: Negative for metastases
  • PFTs: FEV1 78% predicted, adequate for surgery
  1. Multidisciplinary Tumor Board:
  • Thoracic surgery, medical oncology, radiation oncology, pulmonology
  1. Treatment Plan:
  • Stage IA2 disease: Surgical candidate
  • Video-assisted thoracoscopic surgery (VATS) right lower lobectomy with mediastinal lymph node dissection
  • Final pathology: pT1bN0M0, Stage IA2
  • No adjuvant therapy recommended for Stage IA
  1. Surveillance:
  • CT chest every 6 months for 2 years, then annually
  • Smoking cessation counseling reinforced
  • PCP follow-up for ongoing lung cancer screening of remaining lung

Radiological Image

Image Description: CT-guided percutaneous lung biopsy demonstrating the biopsy needle positioned within a peripheral lung nodule. CT guidance allows real-time visualization of needle trajectory and confirmation of accurate sampling position within the target lesion.

Source: Radiopaedia - Educational image of CT-guided biopsy URL: https://radiopaedia.org/articles/ct-guided-lung-biopsy License: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported

Learning Points

  1. TACE for HCC: Transarterial chemoembolization exploits the dual blood supply of the liver (portal vein supplies normal liver; hepatic artery preferentially supplies tumors). TACE delivers chemotherapy directly to the tumor while inducing ischemia, and can serve as bridge therapy to transplant or definitive treatment for intermediate-stage HCC.
  1. CTA for GI Bleeding: CT angiography can detect active bleeding at rates as low as 0.3-0.5 mL/min and localizes the source for targeted intervention. The sentinel clot sign helps identify the bleeding source. When active extravasation is seen, angiographic embolization often provides definitive hemostasis without surgery.
  1. CT-Guided Biopsy Technique: Coaxial technique allows multiple samples through a single pleural puncture, reducing pneumothorax risk. The tract should be planned to avoid fissures and major vessels. Post-biopsy pneumothorax occurs in 15-20% of cases but most are small and managed conservatively.
  1. Lung-RADS and Nodule Management: Lung-RADS provides standardized reporting for screening CT findings. Category 4B nodules (>15mm with suspicious features) warrant tissue diagnosis. PET-CT helps assess metabolic activity and screen for metastatic disease before proceeding with biopsy.

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