CT features of pulmonary alveolar proteinosis

OBJECTIVE. This investigation describes the CT features of pulmonary: alveo lar proteinosis in a large group of patients. MATERIALS AND METHODS. A retrospective review of 139 chest CT scans (79 thi ck-section scans and 60 thin-section scans) from 27 patients with pathologi cally proven pulmonary alveolar proteinosis was performed. Two independent observers assessed the intraslice patterns and zonal distribution of diseas e on three CP images of each lung. The observers also graded the percentage of ground-glass opacities, air-space opacities, fibrosis, interlobular opa cities, intralobular opacities, and emphysema in each slice. CT scans obtai ned before and after lavage related to 12 whole-lune lavage treatments on n ine patients were evaluated. RESULTS. The dominant intraslice pattern was geographic, but a diffuse patt ern was sometimes seen. The most common zonal pattern was uniform; a lower zone predominance was next most frequent. Ground-glass, air-space, and fibr otic opacities had a generally homegeneous craniocaudal distribution, but t here was a trend toward more interlobular opacities at the lung bases (p < 0.002), Ground-glass opacities were seen on at least one scan in 100% of th e patients. Interlobular opacities (85%), air-space opacities (78%), substa ntial fibrosis (7%), anti intralobular opacities (7%) occurred less frequen tly. Compared with thicksection images, thin-section imanes showed more int erlobular opacities, but Ilo difference in ground-glass, air-space, or fibr otic disease. The proportion of lung affected by ground-glass and interlobu lar opacities decreased significantly (p < 0.05) after lavage. CONCLUSION. Pulmonary alveolar proteinosis does not present only with alveo lar disease. The CT appearance typically combines different types of opacit ies with a geographic pattern and a uniform zonal distribution with variati on over time.