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Transthoracic percutaneous fine-needle aspiration


Medical editor Audun Berstad MD
Radiologist

Oslo University Hospital
Norway

General

CT-guided transthoracic fine-needle aspiration cytology (FNAC) or biopsy is carried out when it is difficult to obtain representative material using bronchoscopy. This applies especially if the lesion is situated peripherally in the lung. 

The technique has high diagnostic precision, with a sensitivity and specificity over 90% for identifying malignancy. In patients who are not suitable for surgery and who have a peripheral tumor, this technique may be crucial for making a correct diagnosis. 

If the lesion is in contact with the pleura or thoracic wall, the procedure can often be carried out using ultrasound guidance.

Indication

  • Tumor-suspect lung lesion

Goal

  • Obtain representative material from the lesion to make a cytological or histological diagnosis

Equipment

  • Introducer needle
  • Needle for aspiration
  • Biopsy pistol adjusted for the introducer

Preparation

The patient must have sufficient heart/lung capacity to be able to tolerate a complication such as a pneumothorax or bleeding. The patient must be able to cooperate and hold their breath for at least 10 seconds and without coughing.

If recent CT images are not available, or previous images are not of sufficient quality, a new series are taken before the procedure is performed, usually with intravenous contrast fluid. 

A point for puncture is planned based on the CT images. Images acquisition is done while the patient holds their breath after a "normal" exhalation. If this is not possible, the patient should hold their breath during the inhalation. Based on the measurements from the CT images, the puncture point is marked on the patient's chest. 

  • The patient lies in a position suitable for insertion of the needle.
  • The procedure is carried out using local anesthesia.
  • The area is washed and covered with a sterile surgical drape.

Implementation

  • The anesthesia needle is inserted gradually as the local anesthetic is injected.
  • The position and direction are checked at regular intervals with CT.
  • When the anesthesia needle is by the pleura, the rest of the anesthetic is injected. It is important not to puncture the pleura with the anesthetic needle.
  • The needle is retrieved.
  • An introducer needle with stiletto is inserted through the pleura and into the lesion. The needle should be inserted through the pleura only once.
  • An aspiration needle is placed in the introducer which is connected to the aspiration syringe with an adapter.  
  • The patient should hold their breath during sampling.
  • The material is aspirated from the lesion and is smeared onto a microscope slide and stained. It may be necessary to take samples for microbiological testing and culturing and possibly multiple pistol biopsies with small deviations in the angle of the needle.

A small pneumothorax is relatively common (40%). Most occur during the examination and will disappear without treatment. Occasionally, a chest tube is needed.


Follow-up

Serious complications are very rare.

  • An X-ray of the thorax is taken 2 hours after the procedure.
  • A small amount of bleeding around the puncture canal is common. This is usually minor and stops quickly.
  • The patient may have some bloody expectorate.
  • If there are no complications and the patient does not have serious comorbidities, he/she may return home the same day.
  • The results from the test are usually available after 2 days.

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