Smaller and deeper lesions increase the number of acquired scan series in computed tomography-guided lung biopsy.

PURPOSE

To determine factors influencing the number of acquired scan series and subsequently the radiation dose and time during computed tomography (CT)-guided lung biopsies.

MATERIALS AND METHODS

This Health Insurance Portability and Accountability Act-compliant, institutional review board-approved, retrospective study reviewed 50 consecutive procedures. Each procedure was separated into the following steps: trajectory planning, needle placement, needle insertion (extrapulmonary and intrapulmonary), and sampling and follow-up. The number of scan series, time, and radiation dose were calculated for each procedure and its steps. The effects of patient characteristics (age, sex, history of surgery that violated the pleura), procedure characteristics (needle-pleural angle, patient position), and lesion characteristics (size, depth, lobar location) on the number of scan series for the procedure and each step were evaluated using stepwise linear regression. The overall diagnostic accuracy, pneumothorax rate, and chest tube insertion rate were also calculated.

RESULTS

The mean number of total CT scans was 21, the mean effective dose was 14 mSv, and the mean entrance skin dose was 249 mGy. On average, trajectory planning and needle insertion contributed most to the number of scan series (18.5% and 52.9%, respectively). For trajectory planning, a smaller lesion size and shallower needle-pleural angle were associated with an increased number of scans (R(2)=0.200, P=0.005). During needle insertion, smaller lesions were associated with increased scanning (R(2)=0.296, P<0.001), with both smaller and deeper lesions associated with an increased number of scans during the intrapulmonary component (R(2)=0.372, P<0.001). For the entire procedure, smaller lesions were associated with an increased number of scans (R(2)=0.12, P=0.01).

CONCLUSION

Lesions that are smaller or deeper in the lung result in a higher number of CT scans, resulting in increased radiation dose and procedure time, with most of these performed during the needle insertion step.