Displacement of coils into the lung during embolotherapy: Clinical importance and follow-up with helical CT

Rationale and Objectives. The authors performed this study to evaluate the clinical importance and computed tomographic (CT) appearance of coils displaced into the lung during embolotherapy. Materials and Methods. The authors retrospectively studied clinical charts and serial chest images from 25 consecutive patients after coil embolization. Chest radiography was performed in all patients, whereas helical chest CT was performed only in patients in whom dislocated coils were visible on chest radiographs. Coils were applied for the treatment of peripheral arteriovenous (AV) malformations and fistulas (n = 9), renal AV malformations or fistulas (n = 8), and primary or secondary tumors (n = 8). Clinical charts were analyzed for short- and long-term symptoms; chest radiographs and CT scans were reviewed for signs indicative of pulmonary infarction. Results. None of the patients had clinical symptoms suggestive of pulmonary infarction. In two of the 25 patients (8%), displaced coils were seen in the pulmonary vasculature at chest radiography; these patients had been treated for renal AV fistula and peripheral AV fistula, respectively. One patient had two coils in the left hemithorax (upper and lower lobe), and the other patient had two coils in the right hemithorax (middle lobe), Neither of the patients had abnormalities suggestive of pulmonary infarction at helical CT. Conclusion. Chest radiography can help confirm the presence of coils displaced to the pulmonary vasculature during embolotherapy. Helical CT can also help rule out the presence of coil-associated pulmonary infarction.