Zhang HF, et al. - The researchers here aimed to determine whether the lowest value of lung radiodensity along the passage of the biopsy needle is a quantitative predictor of pneumothorax. In the current work, the lowest value of lung radiodensity along the needle passage was a quantitative predictor of pneumothorax. An independent risk factor for pneumothorax was a value of –850 HU or less. They found that there was a higher risk of occurrence of more severe pneumothorax in association with a decrease in this value.