Cryptogenic organizing pneumonia: CT findings in 43 patients

OBJECTIVE. Description of the CT findings of cryptogenic organizing pneumonia has been limited to a small number of cases. This study was performed to characterize the CT findings of this disease in a larger number of cases and to compare the findings in immunocompetent and immunocompromised patients. MATERIALS AND METHODS. The CT scans of 43 (32 immunocompetent and 11 immunocompromised) patients who had biopsy-proved cryptogenic organizing pneumonia were reviewed. The scans were obtained by using contiguous 8- or 10-mm collimation and selected thin (1.5 or 2.0 mm) section (n = 23), thin- section collimation at 10-mm intervals (n = 12), or 8- or 10-mm collimation only (n = 8). The scans were analyzed by three observers, and final decisions were reached by consensus. RESULTS. The most common pattern seen was consolidation, which was present alone or as part of a mixed pattern in 34 cases (79%). The consolidation had a predominantly subpleural and/or peribronchovascular distribution in 27 cases (63%). Ground-glass attenuation and nodules were seen in 26 patients (60%) and 13 patients (30%), respectively, and were usually random in distribution. Consolidation was present in 91% (29/32) of immunocompetent and 45% (5/11) of immunocompromised patients (p < .01). Ground-glass attenuation was present in 56% (18/32) of immunocompetent and 73% (8/11) of immunocompromised patients (p > .25). Nodules were present in seven (22%) of 32 immunocompetent patients and six (55%) of 11 immunocompromised patients (p < .025). CONCLUSION. We conclude that in immunocompetent patients the CT findings in cryptogenic organizing pneumonia most commonly consist of bilateral areas of consolidation involving mainly the subpleural and/or peribronchovascular regions. In the immunocompromised patient, the CT findings are variable.