肾移植术后肺部感染的CT特征

Pulmonary infections after kidney transplantation： analysis of CT findings

目的回顾分析121例临床证实的肾移植术后肺部感染患者的临床及CT资料，以期获得肾移植术后肺部感染的特征性CT表现。方法临床证实的肾移植术后肺部感染446例患者，行感染时间分析，其中有完整胸部CT检查资料的121例行病原种类及CT表现分析；影像结果分析采用X2检验及Fisher’s精确检验。结果（1）肺部感染时问特点：446例肾移植患者术后1个月内发病65例（14．6％），1—3个月147例（32．9％），4～6个月91例（20．4％），7～12个月23例（5．2％），1年以上120例（26．9％）。移植术后1个月内细菌感染比例高（4／5）；第1～6个月细菌（34／41，82．9％）、混合感染（19／41，46．3％）以及病毒感染（19／41，26．8％）为主；1年以后真菌（14／38，36．8％）、结核杆菌（5／38，13．2％）感染率明显增加。（2）病原体分布：121例行CT检查的肺部感染中细菌（34例，28．1％）和混合感染（34例，28．1％）最为常见，真菌（9例，7．4％）、结核（7例，5．8％）感染次之，病毒感染（5例，4．1％）最少。（3）CT特征：肾移植后肺部感染CT征象出现最多的是磨玻璃影（GGO）（69例，57．0％），其他依次为网格或线样影（68例，56．2％）、结节（66例，54．5％）、胸膜增厚（41例，33．9％）、实变（31例，25．6％）、树芽征（24例，19．8％）、胸腔积液（22例，18．2％）以及血管支气管束增粗（16例，13．2％）等征象，其中巨细胞病毒感染中以弥漫型GGO最常见（4例，80．0％），在细菌感染中结节最常见（23例，67．6％），树芽征在结核中最常见（4例，P=0．049），其他征象在各病原体感染中出现频率差异无统计学意义（P值均〉0．05）。结论肾移植后肺部感染高峰为术后3个月左右；最常见的病原体是细菌，混合感染比例高；CT表现多样，需结合术后时间、实验室资料及病变分布等才能作出明确诊断。

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 test. 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%） after 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 mycobacterial（5/38,13.2% ）infections was increased after 12 months of transplantation. （2）Pathogens： Bacterial（ 34,28% ）and mixed infections （34,28%）were the most common, followed by fungus infection （9, 7% ） ,TB（7,6% ）and cytomegalovirns （5,4%）. （3）CT findings： Ground-glass 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 differences in the prevalence of other CT patterns（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 infection can be made by combining the time course of infection, clinical laboratory data and lesion distribution.