Wegener granulomatosis: CT features of parenchymal lung disease.

Chest CT from eight patients with pulmonary Wegener granulomatosis were reviewed. The CT features of parenchymal lung involvement included multiple nodules or masses (seven of eight; 88%), ranging in size from 0.3 to 5.0 cm. Lung nodules demonstrated distinct feeding vessels in seven of eight patients (88%); and lesions similar to pulmonary infarcts, i.e., peripheral wedge-shaped lesions abutting the pleura, were identified in seven cases (88%). Scarring, spiculation, and pleural tags emanating from pulmonary nodules were prominent features (seven of eight; 88%). Other findings included cavitation (four of eight; 50%), air bronchograms through nodules (two of eight; 25%), and pleural effusions (two of eight; 25%). One patient on immunosuppressant therapy also demonstrated scattered ground glass infiltrates due to complicating pneumocystis pneumonia. In comparison to corresponding conventional chest radiography, CT examinations revealed more parenchymal lesions in five of eight cases (63%) and bilateral disease instead of unilateral disease in one of eight cases (13%). Feeding vessels were only identified on CT. Wegener granulomatosis is a primary necrotizing granulomatous vasculitis, and when it affects the lung it demonstrates CT features that are similar to other vessel-related disorders of the lung such as septic emboli, pulmonary infarcts, and tumor emboli of hematogenous metastases. We believe that these CT features--nodules with feeding vessels and wedge-shaped lesions abutting the pleura--are related to the necrotizing angiitis that affects pulmonary arteries and veins in this disease.