关键词: 肺泡蛋白沉积症, 容积数据高分辨率CT, 诊断

Abstract: Background　At present，the diagnosis of pulmonary alveolar proteinosis（PAP） still needs bronchialveolar lavage and/or lung biopsy，which belongs to invasive examination.Chest CT plays an important role in the diagnosis of PAP，especially low-dose volume data high resolution CT（VHRCT），which can show more anatomical details and characteristics of lesions，thus providing help for clinical diagnosis.But there are few reports in this regard.Objective　To observe the imaging findings of PAP before and after treatment with low-dose VHRCT，and to explore the clinical value of low-dose VHRCT in PAP diagnosis.Methods　Clinical data，chest low-dose VHRCT data，diagnosis and treatment of 24 patients who were diagnosed as pulmonary alveolar proteinosis and treated in West China Fourth Hospital，Sichuan University from June 2015 to June 2018 were retrospectively analyzed.Results　Before treatment，24 patients had multiple ground-glass opacities with clear borders and blurred margins in both lungs；12 had wide distribution of ground-glass opacities，showing a geographic appearance；seven had localized patchy consolidation in both lungs；six had thickened interlobular septum，presenting crazy paving pattern；three had large area shadows outward projection from both hilus pulmonis，distributing like butterfly wings，and two had pneumatic bronchus sign.In some cases，multiple micro-nodules and interstitial fibrosis were seen in both lungs.No enlarged lymph nodes in mediastinum and hilus pulmonis was found in 24 cases.In the same case，the above-mentioned imaging findings appeared simultaneously.In the course of follow-up and review after treatment，these ground glass opacities of 24 cases were reduced in scope，decreased in density and clear in edge；four cases of consolidation shadow were transformed ground-glass opacity，two cases of pneumatic bronchial sign.Sixteen cases were diagnosed by bronchoalveolar lavage，three cases by serum granulocyte macrophage- colony stimulating factor（GM-CSF） antibody detection，and five cases by lung biopsy.According to VHRCT characteristics of PAP，16 cases were correctly diagnosed，with the accuracy rate of 66.7%（16/24）．Five cases were misdiagnosed as bacterial pneumonia，two cases as pulmonary edema and one case as idiopathic pulmonary interstitial fibrosis.After treatment，the clinical symptoms such as dyspnea and cough were relieved.Total lung capacity/estimated value（TLC%），diffusing capacity of the lungs for carbon monoxide/ estimated value（DLCO%），vital capacity / estimated value（VC%），pH，and oxygen partial pressure（PaO2） were higher after treatment，while the partial pressure of carbon dioxide（PaCO2） after treatment was lower than that before treatment（P<0.05）．Conclusion　The low-dose VHRCT of PAP showed ground glass opacity and/or consolidation with extensive or limited distribution.The “map pattern” and “crazy paving pattern” had certain characteristics，and some cases showed "butterfly wing pattern" and pneumatic bronchial sign.In addition，the disease generally had no enlargement of mediastinal and hilar lymph nodes.It is helpful for the diagnosis，severity evaluation and curative effect observation of pulmonary alveolar proteinosis，and can be used as a routine examination.

Key words: Pulmonary alveolar proteinosis, Volume data high resolution CT, Diagnosis