Application Of MR Diffusion Weighted Imaging In Differential Diagnosis Of Pulmonary Tuberculosis And Comsolidation Pneumonia

Objective: This study aims to explore the application value of MRI diffusion weighted imaging in the diagnosis and differential diagnosis of pulmonary tuberculosis and solid pneumonia and its clinical significance,and conducts preliminary research and analysis on the correlation of the ADC value of lung lesions with lesion composition.Method: This experiment was designed as a retrospective study.Collect 67 cases of tuberculosis and pneumonia who were treated and received CT examination in our hospital from December 2015 to May 2016,including 36 cases of male patients and 31 female patients,aged 11 to 76 years old,average age 44±10.3 years old.The number of lesions was 72 altogether.All cases were confirmed by CT images.Among them,27 cases mainly manifested as pulmonary tuberculosis,12 cases as cavitary pulmonary tuberculosis,11 cases as tuberculoma,and 17 cases as solid pneumonia.The tuberculosis group: there were a total of 50 cases of pulmonary tuberculosis,including 34 cases of male patients and 16 cases of female patients,aged 16 to 76 years old,average age 46 years old.There were 46 cases with clinical symptoms,including 16 cases with fever,22 cases with cough and sputum,and 8 cases with hemoptysis;4 cases with no obvious clinical symptoms.All of the cases were secondary pulmonary tuberculosis,including 30 cases with increased erythrocyte sedimentation,33 cases were tuberculin test positive,and 17 cases of patients were detected as negative.At the same time,collect 17 cases of solid pneumonia as pneumonia group.The pneumonia group: 11 male cases and 6 female cases,aged 12 to 60 years old,average age 34 years old.The CT images mainly showed that the minimum diameter of lobe primarily affected by consolidation was no less than 3 cm.Above mentioned focal solid parts had a minimum section diameter of no less than 3 cm.The patients contained in this experiment had no diabetes,urinary system,blood system and immune system diseases.Their pneumonia were mainly exudation and consolidation,the minimum section diameter was no less than 3 cm,and the internal part of the lesions may be associated bronchial inflation.Clinical diagnosis should also be combined(with typical clinical symptoms of infection,clinical signs,clinical physical examination,matching laboratory examination of white blood cells and neutrophils change,and matching infectious lesions imaging).Apply review 1to2 weeks after lesions treatment,and those whose lung lesions disappeared or significantly absorbed and improved were included in the object.The tuberculosis group: tuberculosis(consolidation,cavitary,tuberculoma).The pneumonia group: solid pneumonia(lobar pneumonia,lung abscess,consolidation caused by other bacteria).Pulmonary tuberculosis should contain large nodules or consolidation lesions whose minimum section diameter were no less than 3 cm and the internal part of the lesions had visible bronchial inflation and occasionally multiple cystic lucent area,including bacterial positive pulmonary tuberculosis and bacterial negative pulmonary tuberculosis(diagnostic criteria for bacterial positive pulmonary tuberculosis: newly diagnosed sputum smear microscopy for acid fast bacilli positive for 2 times(+),or 1 smear positive plus 1 culture positive,or even 1 smear positive,but the clinical manifestation and the imaging findings were in support of secondary pulmonary tuberculosis.Diagnostic criteria for bacterial negative pulmonary tuberculosis: newly diagnosed sputum smear microscopy negative 1 time,1 culture negative with tuberculosis imaging).The cases are 24 cases of tuberculosis group,and 6 cases of pneumonia group,with biopsy or surgical pathology results.Magnetic resonance scanning using SEIMENS Avanto1.5T superconducting magnetic resonance scanner(MRI)imaging system,body phased array surface coil imaging.All patients received 64 slice spiral CT scan,and MR conventional T1 WI,T2WI,fat suppression,DWI different b values(0,500,800s/ mm2)scanning,and formed DWI images and ADC images with different b values.Measure the DWI signal intensity and ADC value under different b values,and select the best b value and scan scheme according to the signal-to-noise ratio(SNR)and clutter-to-noise ratio(CNR).Apply the following analysis: to observe the imaging features of DWI measurement and ADC diagram,calculate and compare SNR and CNR under different b values,and select the best b value;under the best b value,apply ADC value quantitative analysis of solid pneumonia,solid tuberculosis and cavitary tuberculosis,and conduct related research and analysis on cavitary tuberculosis and solid tuberculosis.Results: In T1 WI images,the level of spinal cord lesion/signal ratio of pulmonary tuberculosis group and solid pneumonia group both were close to 1.00,and there was no significant difference;in T2 WI images,the lesions/spinal cord signal ratio of pulmonary tuberculosis group was greater than the solid pneumonia consolidation group(P<0.001).Compare ADC of various types of pulmonary tuberculosis lesions and solid pneumonia: the ADC value of solid pneumonia group(17 cases)was higher than the solid tuberculosis group(27 cases)(P=0.015);the ADC value of solid tuberculosis group(27 cases)and tuberculoma group(11 cases)were higher than the cavitary tuberculosis group(12 cases)(both P<0.001);there was no significant difference between the ADC value of solid tuberculosis group(27 cases)and tuberculoma group(11 cases)(P=0.209);there was no significant difference between the ADC value of solid pneumonia group(17 cases)and tuberculoma group(11 cases)(P=0.505).Conclusion: The ADC value of solid pneumonia was higher than that of solid pulmonary tuberculosis,tuberculoma and cavitary pulmonary tuberculosis,and in T2 WI,tuberculosis lesions/spinal cord signal ratio was greater than that of solid pneumonia.DWI could be used as an important means of differential diagnosis of pulmonary tuberculosis and solid pneumonia besides CT.