3) Complications A.- Unspecific Complications The technique used has been proven safe in this small subset of patients (1-3). Some patients treated by CT- guided seed implantation developed complications such pneumothorax, pleural effusion or hemothorax (Fig ). Although these patients had a poor baseline respiratory function, no significant effects were noted because pneumothorax was diagnosed during the implantation procedure and was immediately resolved with the patient closely monitored under general anesthesia (3) (Fig 14). We have seen free pleural effusion (PE) with typical and atypical presentation (7), and PE in major fissure.

Pneumothorax in an 85- year-old male, caused during the implantation of radioactive seeds in lung cancer (arrow at A). The nodule was separated from the thoracic wall during puncture (arrow at B) owing to the pneumothorax (C). At this moment, a drainage tube was inserted, and the procedure was completed 4 days later (D). A B CD

Fig 15.-Three different patients treated with PIB who presented free pleural effusion with typical (arrow at A), and atypical presentation (arrow at B) (7) and effusion within the mayor fissure (straight arrow in C). Subcutaneous emphysema (curved arrows). A BC

3) Complications B.- Specific Complications These are caused by the migration of seeds and by their ionizing action in the lung (7). Very few cases of pneumonitis secondary to PIB seeds have been described (8). The seeds can migrate to the heart (Fig 16) or the pulmonary arteries (Fig 17), where they may cause pneumonitis (Fig 18). No clinical signs or symptoms nor dosimetry changes were detected in these patients (6). Very few cases of pneumonitis secondary to PIB seeds have been described (8). The seeds can be identified in the pleural cavity (Fig 19). We have seen a patient with azygos lobe, with azygos vein migration to the mediastinum and vanishing azygos lobe simulating recurrence (Fig 20).

Fig year-old man with right lung neoplasm treated with PIB. RS are seen at left heart ventricle (arrow at B) four years after PIB was performed (A-C). Pericardial effusion. Patient had no neurlogical symptoms during these four years. RS are not seen before RS implantation (D). ABC D

Fig 17.- Axial MDCT image shows a migrated seed five days before PIB procedure (arrow at A ). ). No findings of lung disease are observed four years after PIB (B and C). Note the hard beam artifact (B and C). ABC

BAC D Fig 18. Pulmonary arterial embolism produced by migrated RS (arrow at A) that is not seen on MDCT images taken before PIB (B). A small linear opacity with hard beam artifact is seen two months after PIB (arrow at A). High density was seen in lung surrounding the RS ten month before PIB was performed. This finding is consistent with pneumonitis (arrow head at C). To our knowledge there are no published cases of migrated RS in thoracic PIB with neumonitis. RS is better seen in images with bone window (D) than in lung window (A and C) (6).

Fig year-old patient with neoplasm in left lower lobe. 66 days after PIB, three seeds can be identified in the pleural cavity (arrowhead at A) and pneumothorax (arrow at B). These findings may suggest the presence of a broncho-pleural fistula.

A B C D E F Figure 20.- Figure 20.- Lung neoplasm (arrow at A) diagnosed by cytology. Right pneumothorax occurred when the diagnostic fine needle aspiration was performed. It was treated with Palladium seeds (arrow at B). A second pneumothorax occurred after the implantation of the seeds. CT performed seven months after seed implantation shows seeds that have migrated into pulmonary arteries (arrow at C). Azygos fissure is present (arrowheads A and B). Six months later, the azygos vein was found in the mediastinum (large arrows D and E). The fissure disappears (F). The apical arteries with seeds can be identified grouped together next to the pulmonary nodule (small arrows at D and E). The nodule seems to have grown, simulating relapse. The azygos vein has migrated to the mediastinum, the azygos lobe has disappeared, and the lung has been displaced upwards, probably as a result of fibrosis. ( Villanueva A, Cáceres J, Ferreira M, Broncano J, Pallisa E, Bastarrika G. Migrating Azygos Vein and Vanishing Azygos Lobe: Mdct Findings for Six Patients. Am J Roentgenol 2010; 194:1–5.)