免疫抑制兔肺部真菌感染早期薄层CT表现与病理对照研究

目的 比较免疫抑制兔肺部感染白念珠菌、曲霉菌、隐球菌的薄层CT表现并与病理对照,以加深对肺部真菌感染早期表现的认识,提高临床诊断准确性.方法 建立免疫抑制兔肺部感染白念珠菌、曲霉菌及隐球菌动物模型后,各实验组及对照组行CT扫描观察CT表现,并与病理作对照研究;免疫抑制剂使用前后兔静脉血中性粒细胞值比较采用配对t检验,CT征象及病灶分布比较采用x2检验及Fisher's 精确检验,CT出现病变的时间比较采用独立样本t检验.结果 白念珠菌实验组17只中14只建模成功,隐球菌实验组19只中16只建模成功,曲霉菌实验组17只中15只建模成功;实验动物免疫抑制剂使用前后中性粒细胞值比较:白念珠菌组分别为(2.91±0.92)、(0.35±0.19)×109/L,差异有统计学意义(t=12.484,P＜0.05);曲霉菌组分别为(2.51 ± 0.82)、(0.76 ±0.71)×109/L,差异有统计学意义(t=5.792,P＜0.05);隐球菌组分别为(2.10±0.65)、(0.48±0.22)×109/L,差异有统计学意义(t=8.199,P＜0.05);3种真菌性肺炎胸部CT出现病变时间(白念珠菌组平均为接种后4.36 d,曲霉菌组5.86 d,隐球菌组3.69 d)比较差异无统计学意义(P值均＞0.05);14只白念珠菌肺炎兔中,磨玻璃影(GGO)10只,实变8只,结节1只,病灶累及双肺7只;15只熏烟色曲霉菌肺炎兔中,GGO 13只,实变4只,结节1只,双肺受累9只;16只新生隐球菌肺炎兔中GGO 10只,实变5只,结节1只,病灶累及双肺6只;病理上GGO主要为肺充血、出血、间质增生及炎细胞浸润,肺实变则提示较严重的充血、出血、间质增生、炎细胞浸润及组织坏死与血管栓塞出现.结论 免疫抑制兔肺部白念珠菌、曲霉菌及隐球菌肺部感染模型有较高的建模成功率,3种真菌病变早期在CT上以GGO、实变和结节表现为主,3种真菌性肺炎的早期表现相仿,没有明显差别;其薄层CT表现基本反映病理变化.

Fungus infection in immunocompromised rabbits:correlation of thin-section CT findings and histopathology

Objective To compare the thin-section CT findings of pulmonary candidiasis,aspergillosis and eryptococcosis wim histopathology in immunoeomprimised rabbits and impmve the diagnostic accuracy of fungus infection. Methods Heathy New Zealand white rabbits were used for immunoeompromised animal models.Thin-section CT scan was performed before and 2,4,6,8,10,12,14 d after inoculation.The pattern and distribution of the pulmonary abnormalities were retrospectively assessed by two thomeic radiologists and compared with histopathology.The granulocyte count was compared before and after administration of immunosuppressive agents.The pmred t test,chi square test and the Fisher's exact test were used for the statistics.Results Fourteen rabbits had candidiasis.16 rabbits had cryptocoecosis,15 rabbits had aspergillosis.The granulocyte counts before and after administration of immunosuppressive agents were(2.91±0.92)and(0.35±0.19)×109/L respectively in eandidiasis group,there was a significant difference(t=12.484,P＜0.05);(2.51±0.82)and(0.76±0.71)×109/L in aspergillosis group,there was a significant difference(t=5.792,P＜0.05);(2.10±0.65)and (0.48±0.22)×109/L in cryptococcosis group,there was a significant difference(t=8.199,P＜0.05).The onaet time of infections on CT were not significantly different in three groups (P＞0.05).Ground glass opacity (GGO) and consolidation were the two most colnlnon findings in immunocompromised rabbits with three fungus infections,areas of GGO was correlated with the congestion,hemorrhage,inflammatory cell infiltration and interstitial hyperplasia in pathology. Consolidation was correlated with the severe congestion,hemorrhage, inflammatory cell infiltration, interstitial hyperplasia, necrosis and vascular embolism in pathology. Conclusion GGO and consolidation are the two most common findings of fungus infections in immunocompromised animal models and thin-section CT findings can reflect the pathological changes.