Computed tomography of folded lung.

Computed tomography (CT) scans of 22 examples of folded lung in nine patients were reviewed. The most important CT criteria of folded lung are the presence of vessels and bronchi running in a smooth curvilinear fashion towards a peripheral mass with an ill defined central edge associated with pleural thickening. These features were seen in all 22 examples. The lesions are frequently multiple (eight out of nine patients). When these features are present the diagnosis can be made without recourse to biopsy or thoracotomy. Enhancement with intravenous contrast medium is unnecessary and does not provide any extra useful information. Various other previously described criteria such as air bronchograms are not necessary for the diagnosis.