CT -GUIDED TRANSTHORACIC BIOPSY OF SOLITARY PULMONARY NODULES USING AUTOMATIC BIOPSY GUN

Background: CT –guided percutaneous transthoracic fine needle aspiration biopsy (TFNAB) has become a widely accepted and effective minimally invasive technique for the diagnosis of a variety of intrathoracic lesions that are not readily accessible with bronchoscopy. It is generally regarded as a safe procedure with limited morbidity and extremely rare mortality. It provides high diagnostic accuracy and has a relatively low complications rate.
Objectives: The aims of our study were to report our experience with regard to the accuracy & pneumothorax rate of percutaneous CT-guided biopsy of solitary pulmonary nodules using automatic biopsy gun.
Patients and methods: Between January 2006 and August 2009, 54 patients (46 men and 8 women) with solitary pulmonary nodule underwent CT guided transthoracic biopsy at Al-Kadhimiya Teaching Hospital, Baghdad, Iraq. All the lesions could not be diagnosed with fiberoptic bronchoscopy. CT-guided biopsy was performed with an 18-gauge automatic biopsy gun. Chest radiography was done 2-4hr later and 24hr after biopsy for observation of pneumothorax. The overall diagnostic accuracy, pneumothorax rate, and chest tube insertion rate were determined. Diagnostic accuracy and pneumothorax rate were statistically compared according to lesion size & lesion depth (p value of less than 0.05 was considered to be significant).
Results: Forty one patients (76%) diagnosed as malignant (diagnostic accuracy of 87.8%). Thirteen patients (24%) were diagnosed as benign (diagnostic accuracy of 92.3%). The overall diagnostic accuracy was 89% (48 of 54). The diagnostic accuracy did not differ with respect to the lesions size and lesions depth from the chest wall. Accurate diagnosis was made in 25 of the 29 nodules <20 mm (86%) and in 23 of the 25 nodules 20 mm (92%). Similarly accurate diagnosis was made for 36 (90%) of the 40 nodules shallower than 60 mm and for 12 (85.7%) of the 14 nodules 60 mm. Pneumothorax occurred in 23 (42%) patients. Pneumothorax occurred more frequently in small sized lesions (16 out of 29 lesions measuring <20 mm) as compared to (7 out of 25 lesions 20 mm) (P <0.05). similarly pneumothorax occurred more frequently in deeper lesions (10 out of 14 lesions 60mm in depth) as compared to (13 out of 40 lesions <60 mm in depth) (P <0.05). Only 7 (13%) patients requiring thoracostomy tube placement.
Conclusions: CT- guided biopsy using automatic biopsy gun allowing a specific diagnosis for benign & probably malignant lesions. Diagnostic accuracy was not affected by the size and depth of the lesions. Deeper & small sized lesions have associated with an increased rate of pneumothorax.
Keywords: solitary pulmonary nodule, CT – guided biopsy, automatic biopsy gun