Purpose: To evaluate lung parenchymal density between the lesion and trajectory path during percutaneous coaxial cutting needle lung biopsy (PNLB).

Materials and methods: Retrospective analysis of  179 consecutive patients (106 males, 73 females; mean age 59.16±16.34 years) from November 2012 to November 2014 undergoing PNLB were included.  Mean lung and lesion density were measured in HU.  Lesion location, needle trajectory were measured. Crosstabs, Fischer’s exact test, and Chi-square test were conducted to analyze the categorical variables. Independent t-test and ANOVA test were conducted to analyze continuous and normally distributed variables.  Statistical significance was considered when p <0.05.

Results: Mean parenchymal lung density anterior and posterior to the lesion who sustained a pneumothorax was above -800 HU(p<0.05). Mean distance from the chest wall and the number of pleural masses were significant with the risk of patients having pneumothorax (p<0.05). The mean distance from the skin within the lesion and needle trajectory angle were not statistically different among patients with and without pneumothorax (>0.05).

Conclusion: Lung parenchymal density anterior to the lesion and posterior to the chest wall in the trajectory path is a strong predicting parameter in patients undergoing PNLB who sustained a pneumothorax.

179 patients who underwent CT-guided percutaneous lung biopsies and were classified according to a lung biopsy technique from November 2012 to November 2014 at our institution    

Informed consents were obtained from all patients prior to the lung biopsy.  Coagulation parameters of all patients were checked to ensure platelet counts >50,000/mL and an international normalized ratio <1.5 as recommended in consensus guidelines.  All patients had chest CT scans that were checked and cross referenced with the referring physician and patient history, prior to the procedure.  The scan parameters prior to the biopsy were: detector width 256 x 0.625 mm; pitch 1.1; rotation time 0.4 sec; exposure factors 100 kVp, 200 mA, with z-axis modulation; and a  scanning time of 2.1 sec.  Patients were then positioned in the prone, supine, or lateral decubitus position on the basis of the location of the target lesion to minimize the number of pleural reflections, avoid major fissures, predetermine the needle trajectory, the shortest distance to the lesion, and the amount of lung parenchyma crossed.  Patients were instructed to take a reproducible breath and abstain from talking during scans, needle positioning, and sampling. The localizing CT scan was used to determine the position of the target lesion. By using sterile technique, local anesthesia was employed with 1% lidocaine. A small subcutaneously incisionwas made for needle entry, and a 16-gauge guiding needle was placed to the thoracic wall just proximal to the pleura. Then, subsequently the pleura was passed with a single puncture  (Quick Core, Cook, USA), and the needle was placed into the lesion. Then, the inner part (stylet) of the biopsy needle was removed and the orifice of the needle was water sealed using normal saline while asking patient to breath hold.  Then, the 18-gauge cutting needle was inserted into the lesion over the introducer.   All PNLB was performed by 4 interventional radiologists with a mean of 17-years of experience. Post biopsy limited CT scan was obtained on each patient that underwent lung biopsy to identify complications such as pneumothorax and bleeding. If the pneumothorax was confined and not symptomatic, a repeat limited CT scan was obtained 2 hours post biopsy.  If on repeat scan, the pneumothorax is stable, patients with normal vital signs were sent home with safety instructions. If the pneumothorax increased and or the patients became unstable, an 8 French pleural drain is placed, and the patient is admitted to hospital for 24 hours.