The Value Of Interventional Bronchoscopy Technology Combined Metagenomic Next-Generation Sequencing In Diagnosis Of Peripheral Pulmonary Infectious Lesions

Objective:The value of metagenomic next-generation sequencing(mNGS)in pathogenic diagnosis of infectious diseases has become increasingly prominent.Howe ver,there are rare reports of interventional bronchoscopy technology combined mNGS for the diagnosis of peripheral lung infectious lesions.The present study aims to evaluate the interventional bronchoscopy technologies(radial endobronchial ultrasound(R-EBUS)and virtual bronchoscopic navigation(VBN))combined mNGS in diagnosis of peripheral pulmonary infectious lesions,to explore the factors affecting positivity rate of mNGS analysis in pathogen detection and to evaluate the sequencing results of different bronchoscopy specimens in order to obtain a safe and reliable way for bronchoscopy.Methods:The study enrolled 336 patients who were admitted to the Respiratory Department of General Hospital of Tianjin Medical University from July 2018 to December 2019 and were suspected to have peripheral pulmonary infectious lesions by chest spiral CT.Electronic bronchoscopy was performed in all cases,lung biopsy was performed according to standard procedures.The enrolled patients are divided into groups according to whether radial ultrasound and virtual navigation are used.To explore the value of R-EBUS,VBN and mNGS analysis in the pathogenic diagnosis of peripheral lung infection lesions.To analyze the factors affecting the positivity rate of mNGS analysis.Comparison of mNGS results of three specimens on 60 patients who obtained bronchial brushing,bronchoalveolar lavage fluid and bronchoscopy lung biopsy at the same time.Results:Compared with the non-radial ultrasound group,R-EBUS assisted bronchoscopy and biopsy equipment to determine the location of lesions,and increased the positivity rate of mNGS analysis in transbronchial lung biopsy(TBLB)specimens(78.7%/60%,P=0.026).Multivariate variable analysis was performed on the imaging characteristics of peripheral pulmonary infection lesions in two groups.The positivity rate of mNGS analysis was significantly higher when the radial ultrasound probe was located in the lesions than when the ultrasound probe was adjacent to the lesions(P < 0.030,OR 17.742).The presence of anechoic region and luminescent region in ultrasound images of lesions could reduce the positivity rate of mNGS analysis(P=0.019,OR 17.878,P = 0.042,OR 16.745).Using R-EBUS assisted localization combined VBN guidance couldn ’t improve the positivity rate of mNGS analysis.The positivity rate of mNGS analysis in VBNA group and NVBNA group were 83.3% and 77.8%,respectively,there was no statistical difference in two groups(P=0.338).The VBNA group was better than the NVBNA group in terms of the time to determine the location of lesions and the total bronchoscopy operation time.The difference between the two groups was statistically significant(P values were P<0.01,P=0.047),and the time to determine the location of lesions was(5.9±2.2min)and(7.6±2.1min),the total bronchoscopy operation time was(21.8±4.4min)and(23.0±4.1min),respectively.The positive rate of mNGS analysis with the ultrasound probe located inside or near the lesion were significantly higher than the probe outside the lesion(92.5%,80.4% and 40.7%,P < 0.001).The positivity rate of mNGS analysis that have positive bronchial signs on CT images of lesions was significantly higher than that of negative bronchial signs(91.9%vs37.1%,P < 0.001).To analyze the mNGS results of 60 patients with peripheral lung infectious diseases who obtained specimens from bronchial brushing,bronchoalveolar lavage,and bronchoscopy lung biopsy at the same time.Mc Nemar test was used to compare the positive rate between mNGS analysis and traditional pathogen detection,mNGS analysis was significantly better than traditional pathogen detection(P < 0.001),Kappa value =0.14,P=0.463,suggesting that the poor consistency between two detection methods.The positive rate of mNGS analysis in the diagnosis of lung infections,bacterial infections,fungal infections and mixed infections was significantly better than that of traditional pathogenic tests,which were88.6%vs26.6%,92.5%vs40%,93.3%vs16.7% and 89.5%vs15.8%,respectively(P<0.001).The positive rate and sensitivity of combined bronchoscopy specimens in the diagnosis of lung infections,bacterial infections,fungal infections and mixed pulmonary infections were superior to those of BB,BALF and TBLB,but there was no statistical difference among different bronchoscopy specimens(P > 0.05).The specificity of traditional pathogen detection was up to 95.2%,while that of mNGS analysis was only 66.7%,showing a significant difference between the two detection methods(P < 0.05).Conclusion:R-EBUS and VBN assisted bronchoscopy lung biopsy are safe and effective methods for diagnosing peripheral lung lesions(PPLs).R-EBUS significantly facilitates the accurate insertion of bronchoscope into the lesions,which improves positivity rate of mNGS analysis in pathogen detection.VBN combined R-EBUS can shorten the time to locate the lesions and the total operation time of bronchoscopy,but it fails to further increase the positivity rate of mNGS analysis.Ultrasound characteristics of peripheral lesions,probe position and whether the lesion has bronchial signs were correlated with positivity rate of mNGS analysis.mNGS analysis has higher positivity rate and sensitivity in pathogen detection than traditional pathogen detection.BB and BALF are less invasive.Compared with single bronchoscopy specimens,mNGS analysis in BB+BALF mixed specimens can obtain higher positive pathogen detection rate and sensitivity,and it can replace TBLB specimens for the pathogen diagnosis of peripheral lung infectious lesions.