The Radiological Study Of Specific Infections In Immunocompromised Host

【Background】The pulmonary infections in immunocompromised host is popular.Cryptococcosis is a systemic disease caused by Cryptococcus neoformans.In recent years,there has been a dramatic rise in the incidence of cryptococcosis,especially in immunocompromised patients,such as AIDS people,or those who received organ or marrow transplantation (BMT).The incidence of pulmonary cryptococcosis is next to pulmonary aspergillomycosis among all pulmonary mycosis.The patients with pulmonary tuberculosis admitted to general hospital are often under low immunity condition.The increase of immunocompromised host is an important reason for buildup of pulmonary tuberculosis these years in China.This study includes animal experimentation and retrospective clinical analyses,to respectively aim at the three specific infections: pulmonary mycosis,pulmonary tuberculosis,and cryptococcus meningoencephalitis.PartⅠThe Animal Experimentation on Pulmonary Cryptococcosis in Rabbits—CT Appearances and Pathology Control Study【Objective】To establish the animal model on pulmonary cryptococcosis in New Zealand Rabbits, and to analyze the manifestations of chest computed tomography.【Materials and Methods】Twenty four New Zealand rabbits,male or female,weight 1.5kg-2.5kg,were divided into experimental group and control group.Experimental group included 20 rabbits,and control group included 4 rabbits.To maintain low immune state,experimental group rabbits were treated with Cytarabine,440mg/m2,intravenous injection every day from first day and every other day from sixth day.Blood routine examination was perform on first and sixth day.In prevention from bacterium infections,experimental group and control group were all treated with Vancomycin,15mg/kg,ceftazidime,150mg/kg every day,and Gentamicin,5mg/kg every other day from forth day.The experimental Cryptococcus strain was Cryptococcus neoformans type strain H99A.After resuscitation and activation,the density of suspension was 1.25×108～2.5×108 cfu/ml.All experimental group rabbits and one control group rabbit were treated as percutaneous trache puncture innoculation.After paralysed,the rabbits were fixed on bacteria safety cabinet,held trache,injected with 0.4-0.8ml suspension,then reversed trendelenburg position.The remained rabbits were injected with normal sodium 0.4ml.Chest CT scans were performed every other day after inoculation.After rabbits died, pathology inspection and fungus cultivation were performed.【Results】:Cryptococcus neoformans for cultivation were positive in 19 rabbits of experimental group.Histopathology findings included alveolar wall thickening,interstitial cell hyperplasia,inflammatory cell infiltration(18),lung alveolus exudation,interstitial substance congestion(12),hemorrhagic necrosis(6),hyalinization(1),granuloma formation(5).And Cryptococcus spore were found in interstitial substance and lung alveolus in 5 rabbits.In HE stain,spore was small round vesiculose.In PAS stain cell wall became red.Lung lesions on thoracic CT scan were displayed in fourteen rabbits.Thirteen of them were the type of consolidation.Lesions were multiple and peripheral distributed on each lobe.The rest rabbit's imaging was the mixed type.There were multiple nodules and consolidation on every lobe of right lung.The lesions aggravated in 11 of 14 rabbits when followed up.They became dense and scattered in larger area.The rest 3 rabbits kept invariably.【Conclusion】:Intravenous injection with Cytarabine and percutaneous trache puncture Cryptococcus neoformans spore suspension inoculation are feasible in establishment of the pulmonary cryptococcosis model.Abnormal CT findings often display the type of consolidation,and the lesion distributed in peripheral lung field has close relationship with bronchus,and often occur at the second day after inoculation,which supports that earlier radiological examination is advantageous for diagnosis.PartⅡCT and MRI Findings of Cryptococcus Meningoencephalitis【Objective】:To evaluate imaging appearances of cryptococcus meningoencephlitis,and to study the value of CT and MRI scan in the diagnosis of cryptococcus meningoencephalitis. 【Materials and Methods】:In retrospective study on medical record of all inpatients with CM from 2001 to 2007, 21 patients with complete data,including radiology examinations were collected.9 of them received CT,6 of them received MRI,6 cases received both CT and MRI.21cases included male 13 and female 8,from 8～53 ages.The main clinical manifestations included headache,nauseated,disgorging,and fever.2 cases had underlying diseases,as chronic granulocytic leukemia and systemic lupus erythematosus.【Results】:CT and MRI scans showed as follows:diffues cerebral edema(1 case),multiple patching lesions(4 cases),multiple small abnormally density or signal intensity in basal ganglia or oval area(5 cases),meningeal enhancement(13 cases) and hydrocephalu(5 cases).【Conclusion】:CT an d MRI can provide useful information which are the basis for localization of lesion,ascertaining the extent and type and development stage of lesion,give help to choosing of treatment planning an d estimating prognosis of CM.PartⅢCT Features of Pulmonary Tuberculosis in General Hospital—CT findings of pulmonary Tuberculosis in Immunocompromised and Diabetic Patients【Objective】:To analyze radiological characteristics of pulmonary tuberculosis in general hospital, and to analyze CT features of pulmonary tuberculosis in immunocompromised and diabetic patients,and to assess the value of CT in diagnosis of pulmonary tuberculosis in immmunocompromised host.【Materials and Methods】:In retrospective study on medical record of all inpatients with pulmonary tuberculosis from 2001 to 2007,202 patients with complete data,including chest CT scanning,and laboratory results were collected.All patients were examined with spiral CT.The imaging of 202 patients were analyzed according to distribution and morphous,et al.The radiological features of 45 immunocompromised and diabetic patients of 202 cases (prescribed immunosuppressant 21 cases and patients with diabetes 24 cases) were compared with those of immunocopetent patients.Statistical analysis applied software SPSS16.0.【Results】:202 cases with tuberculosis divided into four types.TypeⅢof 148 cases(73.3%),the most,typeⅣof 49 cases(24.3%),typeⅡof 4 cases and typeⅠof 1 case.CT appearances included consolidation,132(65.2%),pleural effusion,49(24.3%),Spheral Tuberculosis,21(10.3%),cavitation,17(8.4%).Hematogenous dissemination,multiply consolidation and diffused distribution were CT characteristic appearances in 21 patients prescribed immunosuppressant with pulmonary tuberculosis.CT findings of pulmonary tuberculosis in 24 patients with diabetes often included serious consolidation,general distribution,and more chances to combine pleural effusion.The CT appearances in 45 cases of immunocompromised and diabetic patient were serious consolidation,which might not just locate on predilection site. The characteristic appearances of pulmonary tuberculosis under immunocompromised condition were more chances of cavitates formation and bronchus dissemination(P＜0.05).【Conclusion】:The CT scan is of great use in the diagnostic work-up of patients with pulmonary tuberculosis in general hospital and it is helpful in diagnosis and identification of pulmonary tuberculosis in immunocompromised and diabetic patients.The characteristic appearances of pulmonary tuberculosis in immunocompromised and diabetic host are cavitation and bronchus dissemination.