Abstract： Objective To review the CT findings in patients with pulmonary infection after kidney transplantation and to determine the characteristic features in different infections.Methods The medical records were reviewed in 446 patients with pulmonary infection after kidney transplantation and 121 patients who had pulmonary thin-section CT were included in this study.The pattern and distribution of the pulmonary abnormalities were interpreted independently by two thoracic radiologists.Statistical analysis was performed using the X2 test and the Fisher's exact teat.Results (1)Time course:65(14.6/) patients initially had pulmonary infection in the first 30 days,147(32.9/)between 1 and 3 months,91(20.4/)between 3 and 6 months,23(5.2/)between 6 and 12 months,120(26.9/)afler 12 months of transplantation.In the first month after procedure,bacterial infection(4/5,80.0/)was the most common infection,bacterial(34/41,82.9/)、mixed(19/41,46.3/)and virus infections(11/41.26.8/)were seen commonly 1 to 6 months following transplant,the incidence of fungal(14/38,36.8/)and myeobaeterial(5/38,1 3.2/)infections was increased after 1 2 months of transplantation.(2)Pathogens:Baeterial(34,28/)and mixed infections(34,28/)were the most common,followed by fungus infeetion(9.7/),TB(7,6/)and eytomegalovirus(5,4/).(3)CT findings:Ground-galss attenuations(69,57.0/)was the most common findings of pneumonia,followed by reticular or linear opacities(68,56.2/),nodules (66,54.5/),pleural thickening(41,33.9/),consolidations(31,25.6/),tree-in-bud patterns(24,19.8/),pleural effusion(22,18.2/),and bronchovascular bundle thickening(16,13.2/).Ground-glass attenuation was commonly seen in cytomegalovirus pneumonia (4,80.0/),and nodule was commonly observed in bacterial infection(23.67.6/),tree-in-bud pattern was the most common finding in pulmonary tuberculosis (4.P=0.049).There were no statistically significant difierences in the prevalence of other CT paRerns (P＞0.05).Conclusions The peak incidence of pulmonary infection is in the 3 month after renal transplantation and bacterial infection is the most common.The CT diagnosis of infeetion can be made by combining the time course of infection,clinical laboratory data and lesion distribution.