Abstract: Objective:To investigate the CT findings and follow-up variation of multiple traumatic lung pseudo-cysts.Methods:The data of 30 cases of multiple traumatic pseudo lung cysts confirmed by clinical and imaging follow-up were retrospectively analyzed.Results:Most cases combined with pulmonary contusion,rib fractures,hemopneumothorax.Traumatic pseudocysts in all cases are multiple,an average of 4.6 lesions,size:4mm ×6 mm~13.5 cm × 6.2 cm.First CT examination from 1 hour to 5 days after trauma,and were followed up for 1 day to 15 months,with an average of 4.3 months.The first CT may show multiple simple hematoma,pulmonary contusion merging with multiple hematomas,pulmonary contusion merging with balloon cyst or liquid cyst,multiple airbags cyst or gas cyst.The hematomas lesions near pleural may appear airbag changes again due to hematoma rupture or delayed pneumothorax by rib fractures or other reasons.In the follow-up CT,the simple hematomas may contain with gas or without gas,the rest of the gas-containing lesions may become smaller and consolidation gradually,until completely absorbed or residual cicatricial band.Liquid cysts may be simple or complicated with halo sign.Gas-liquid cysts may appear wedge-shaped sign,silver bracelet sign,water in ball sign or the liquid in the cup sign,peanut shell sign,triangle flask sign and other signs.3 patients died after the CT examination within 2 hours,due to extensive pulmonary contusion and wet lung in 2 cases,liver and spleen bleeding in 1 case.The remaining cases received symptomatic treatment aimed at the accompanying;pulmonary pseudo-cysts were cured by conservative treatment.The absorption time of cysts was positively correlated with the length and size.Conclusion:CT can clearly show the forms,the evolution and the complications of the multiple traumatic lung pseudo-cysts,so it is the best imaging examination method for the diagnosis.