CT Guided and Cone Beam CT Guided Percutaneous Transthoracic Needle Biopsy: A Comparison of Pneumothorax Incidence and Associated Risk Factors

Studies have shown that CBCT is a viable imaging modality for PTNB. Although MDCT-guidance remains the preferred procedural modality, research has shown that CBCT-guided biopsies can be carried out safely and effectively. Particularly, studies demonstrate a satisfactory diagnostic yield, low complication rate, and overall reduced patient radiation dose. However, only a handful of studies have compared this method to MDCT-guided biopsy.

In this 248-bed community hospital-based interventional radiology practice, C-Arm CBCT was successfully utilized during a three-month period when a dedicated procedural CT scanner was out of service prior to the installation of a new machine. During this time, CBCT was used to perform PTNB. This study was prompted given the operators' perception that there was an overall increased incidence of biopsy-associated pneumothoraxes. Given this subjective experience, a retrospective analysis was carried out comparing the complication rate during these three months to the preceding six-month period, when MDCT-guidance was primarily used.

For the primary analysis, patients were grouped based on imaging modality (CBCT n=37; CT n=64). Multiple Pearson Chi-Square Tests were carried out using p=.05 as the statistical threshold. Additional analyses dividing patient based on lesion size (≥/< 2 cm in diameter), lesion pleural depth (≥/< 2 cm pleural depth), bullous lung change on imaging, chest tube placement, history of COPD, and smoking history were also carried out to assess for related pneumothorax risk factors.

The investigators found no significant association between the imaging modality used for PTNB and subsequent pneumothorax (p=.69). However, there was a significant interaction between chest tube placement and diagnosed chronic obstructive pulmonary disease (COPD) (p=.03), where among all study subjects, 6 of the 8 patients requiring a chest tube had a history of chronic obstructive pulmonary disease (COPD). Additionally, all patients requiring chest tube placement were either current or former smokers. This finding approached but did not reach statistical significance (p=0.12).

This study did not confirm the perceived increased pneumothorax rate. However, the findings corroborate previously published literature, where complication rates between CBCT and MDCT-guidance are reportedly comparable. This experience demonstrates that CBCT can be successfully utilized in a community hospital setting, where limited resources often prompt the need for alternative and innovative procedural approaches.