Extrapleural locating method: significance in CT-guided transthoracic pulmonary biopsy

Objective To evaluate the usefulness of extrapleural locating method in CT-guidod transthoracic pulmonary biopsy to prevent or reduce the size of peumothorax.Methods One hundred and fifteen cases of CT-gnided transthoracic pulmonary biopsy with the pulmonary lesions not in direct contact with the pleura were selected.Of 115 cases,46 were performed with extrapleural locating method (EPL) and 69 cases with lesion edge locating method (LEL).Taking the maximum distance between the partial and visceral pleura (MPVD) measured on the CT image after the procedure as the index of the volume of pneumothorax.The incidence and volume of pneumothorax of both groups were compared and statistically analysed with R ×C Chi-Square test.The retention time of the biopsy needle in the lung parenchyma of the two group was documented and the average time was calculated in each group.Results The incidence of pneumothorax was 45.7% (21/46),median 0.4 cm with EPL group,and 66.7% (46/69) and median 0.3cm with LEL group.When the distance between the lesion and pleura was equal or smaller than 2 cm (≤2cm),the incidence of pneumothorax was 39.4% (13/33) with EPL group and 73.2% (30/41) with LEL group,and the difference of incidence and volume of the pneumothorax between two groups was statistically signifieant(X2 =9.981,P =0.019).When the distance was larger than 2 cm( >2 cm),the incidence and volume of pneumothorax between two groups were not significant statistically.The average retention time of the biopsy needle in the lung parenchyma was (7.2±1.8)s with EPL group and (58.3±11.6) s with LEL group.Conclusion The extrapleural locating method can reduce effectively the retention time of the biopsy needle in the lung parenchyma and the incidence and volume of pneumothorax in CT-gnided transthoracic pulmonary biopsy. Key words: Biopsy,needle;  lung;  Stereotaxic techniques;  Tomography,X-ray computed