Objective: To assess the pulmonary CT findings of patients with serum evidence of the myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA).
Methods: The pulmonary CT scans of 62 patients with serum evidence of MPO-ANCA (51 with microscopic polyangiitis, 11 with Churg-Strauss syndrome) were retrospectively assessed with regard to parenchymal, pleural, and mediastinal abnormalities.
Results: On the CT scans, abnormal findings were seen in 51 of the patients (82%, n = 62). Of the patients, the CT findings consisted of ground-glass attenuation in 48 of the patients (94%, n = 51), consolidation in 40 (78%), and thickening of bronchovascular bundles in 26 (51%). Pathologically, these findings corresponded to alveolar hemorrhages, interstitial chronic inflammation in the alveolar septa, vasculitis, or fibrosis. These abnormalities were predominantly seen in peripheral lung parenchyma (n = 37).
Conclusion: The CT findings in patients with MPO-ANCA consisted mainly of ground-glass attenuation and consolidation in the peripheral lung. These findings, although nonspecific, are considered as pulmonary involvement in patients with MPO-ANCA.