Choose the modality that shows the target best, pick the shortest safe path that avoids vessels, bowel, pleura where possible and major nerves, and write down the pre-procedure checks — coagulation, the indication and the tissue the pathologist needs.
Orient first
- Ultrasound is preferred when the target is visible — real-time needle tracking, no radiation, colour Doppler to avoid vessels; CT when the target is deep, behind gas or bone, or in the lung.
- The safest path is not always the shortest: avoid crossing the pleura for an upper abdominal lesion, avoid bowel, and prefer a path through normal parenchyma for subcapsular liver lesions.
- Coagulation thresholds and antithrombotic holding depend on the bleeding risk of the procedure — follow the current society guideline (for example SIR or CIRSE).
Acquire the study
- Planning CT with a grid on the skin; low-dose intermittent CT or CT fluoroscopy during the procedure.
The manoeuvre
- Planning axial slices: entry point, angle and depth in cm to the target.
- Path check on axial and oblique reformats: pleura, bowel, vessels and nerves.
- Coaxial needle placement with confirmation images of the tip within the target.
- Post-procedure scan: pneumothorax (lung window), haematoma.
What confirms it
- A documented path, needle position within the target, and the number and type of samples taken.
What licenses you to exclude it
- A target that cannot be reached safely should be declared as such, with the alternative (another lesion, surgery, endoscopic sampling).
The classic misread
- Sampling the necrotic centre of a mass — aim for the enhancing solid rim seen on the contrast study.