CT guided thoracic biopsy
CT guided thoracic biopsy is usually performed for the diagnosis of suspicious lung, pleural or mediastinal lesions. It can be performed as an outpatient where patient monitoring and complications support are available.
- pulmonary lesion inaccessible to bronchoscopy, or in which prior bronchoscopic biopsy is nondiagnostic
- mediastinal or pleural mass
The contraindications must be considered individually in each case. Overall, the most important contraindication are:
- poor respiratory function or reserve
- uncooperative patient
- lack of safe access
- uncorrectable bleeding diathesis (abnormal coagulation indices)
Laboratory parameters for a safe procedure
Interventional procedures like thoracic biopsy require special attention to coagulation indices. There are widely divergent opinions about the safe values of these indices for percutaneous biopsies. The values suggested below were considered based on the literature review, whose references are cited below:
- complete blood count (CBC)
- platelet > 50000/mm3 (some institutions determine other values between 50000-100000/mm3) 2
- coagulation profile
- international normalized ratio (INR) ≤ 1.5 2
- normal prothrombin time (PT), partial thromboplastin time (PTT)
- some studies showed that having a normal INR or prothrombin time is no reassurance that the patient will not bleed after the procedure 3
Review the diagnostic CT and other relevant imaging first (e.g. PET/CT) to clarify the lesion that is requested to be biopsied. Consideration of the various factors, that influence suitability and degree of risk should be reviewed, including site and size of the nodule/mass and its relationship to structures that must be avoided 3:
- central bronchi
- fissures (it is important to minimize the number of pleural surfaces crossed)
Remember, with cavitating lesions the needle must be targeted to the periphery.
The patient can be positioned prone, supine or laterally depending on the location of the lesion and their respiratory function. Many of these patients will have an underlying respiratory disease and may be unable to lie completely flat.
- a radiopaque grid or skin marker should be utilized to focus the optimal access point then, after preliminary images, this point is marked with a pen.
- make antisepsis and anaesthesia with lidocaine as per institution's protocol.
- a skin orifice is made using a scalpel blade.
- biopsy needle is introduced as previous planning.
- activate biopsy gun.
A period of 'bed-rest' is advised as well as regular observations for some hours after the procedure. The observation period should allow an ample opportunity to identify and treat a potential complication in a timely manner to prevent a serious or catastrophic outcome; it could vary from each institution protocol.
Often, post-procedural x-rays are performed, usually at four hours post biopsy.
- pneumothorax: equal most common; only a small fraction are large enough to warrant insertion of a pleural drain
- haemoptysis: equal most common; occurs in 1-5% of patients 4
- parenchymal haemorrhage: may be seen be noted in ~10% (range 5-16.9%), especially in patients who develop haemoptysis
- air embolism: can be venous or systemic; systemic air embolism occurs in up to 0.2% of patients5
- 1. Li Y, Du Y, Yang HF et-al. CT-guided percutaneous core needle biopsy for small (≤20 mm) pulmonary lesions. Clin Radiol. 2013;68 (1): e43-8. doi:10.1016/j.crad.2012.09.008 - Pubmed citation
- 2. Sue M, Caldwell S, Dickson R et-al. Variation between centers in technique and guidelines for liver biopsy. Liver. 1996;16 (4): 267-270. Liver (abstract) - doi:10.1111/j.1600-0676.1996.tb00741.x
- 3. Walker TG. Interventional Procedures. Lippincott Williams & Wilkins. (2012) ISBN:1931884862. Read it at Google Books - Find it at Amazon
- 4. Manhire A, Charig M, Clelland C et-al. Guidelines for radiologically guided lung biopsy. Thorax. 2003;58 (11): 920-36. Thorax (full text) - doi:10.1136/thorax.58.11.920 - Free text at pubmed - Pubmed citation
- 5. Hare SS, Gupta A, Goncalves AT et-al. Systemic arterial air embolism after percutaneous lung biopsy. Clin Radiol. 2011;66 (7): 589-96. doi:10.1016/j.crad.2011.03.005 - Pubmed citation