Deep Learning-Based Segmentation of Airway Morphology from Endobronchial Optical Coherence Tomography.

BACKGROUND: Manual measurement of endobronchial optical coherence tomography (EB-OCT) images means a heavy workload in the clinical practice, which can also introduce bias if the subjective opinions of doctors are involved. OBJECTIVE: We aim to develop a convolutional neural network (CNN)-based EB-OCT image analysis algorithm to automatically identify and measure EB-OCT parameters of airway morphology. METHODS: The ResUNet, MultiResUNet, and Siamese network were used for analyzing airway inner area (Ai), airway wall area (Aw), airway wall area percentage (Aw%), and airway bifurcate segmentation obtained from EB-OCT imaging, respectively. The accuracy of the automatic segmentations was verified by comparing with manual measurements. RESULTS: Thirty-three patients who were diagnosed with asthma (n = 13), chronic obstructive pulmonary disease (COPD, n = 13), and normal airway (n = 7) were enrolled. EB-OCT was performed in RB9 segment (lateral basal segment of the right lower lobe), and a total of 17,820 OCT images were collected for CNN training, validation, and testing. After training, the Ai, Aw, and airway bifurcate were readily identified in both normal airway and airways of asthma and COPD. The ResUNet and the MultiResUNet resulted in a mean dice similarity coefficient of 0.97 and 0.95 for Ai and Aw segmentation. The accuracy Siamese network in identifying airway bifurcate was 96.6%. Bland-Altman analysis indicated there was a negligible bias between manual and CNN measurements for Ai (bias = -0.02 to 0.01, 95% CI = -0.12 to 0.14) and Aw% (bias = -0.06 to 0.12, 95% CI = -1.98 to 2.14). CONCLUSION: EB-OCT imaging in conjunction with ResUNet, MultiResUNet, and Siamese network could automatically measure normal and diseased airway structure with an accurate performance.

Hierarchical clock-scale hand-drawn mapping as a simple method for bronchoscopic navigation in peripheral pulmonary nodule.

BACKGROUND: A feasible and economical bronchoscopic navigation method in guiding peripheral pulmonary nodule biopsy is lacking. OBJECTIVE: To investigate the utility of hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation in peripheral pulmonary nodules. METHODS: We developed a hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation in peripheral pulmonary nodules. Patients with peripheral pulmonary nodules were recruited and assigned to two groups in this retrospective study, subjects in VBN group received conventional bronchoscopy in conjunction with virtual bronchoscopic navigation (VBN) and radial probe endobronchial ultrasound (RP-EBUS) for biopsy (VBN group), while HBN group underwent ultrathin bronchoscopy and RP-EBUS under the guidance of hand-drawn bronchoscopic navigation (HBN). The demographic characteristics, procedural time, operating cost and diagnostic yield were compared between these two groups. RESULTS: Forty-eight patients with peripheral pulmonary nodule were enrolled in HBN group, while 42 in VBN group. There were no significant differences between VBN and HBN groups in terms of age, gender, lesion size, location and radiographic type. The time of planning pathway (1.32 vs. 9.79 min, P < 0.001) and total operation (23.63 vs. 28.02 min, P = 0.002), as well as operating cost (758.31 ± 125.21 vs.1327.70 ± 116.25 USD, P < 0.001) were markedly less in HBN group, compared with those in VBN group. The pathological diagnostic efficiency of benign and malignant disease in HBN group appeared similar with those in VBN group, irrespective of the size of pulmonary lesion (larger or smaller than 20 mm). The total diagnostic yield of HBN had no marked difference from that of VBN (75.00% vs. 61.90%, P = 0.25). CONCLUSIONS: Hierarchical clock-scale hand-drawn mapping for bronchoscopic navigation could serve as a feasible and economical method for guiding peripheral pulmonary nodule biopsy, providing a comparable diagnostic yield in comparison with virtual bronchoscopic navigation.

A clinical and canine experimental study in small-airway response to bronchial thermoplasty: Role of the neuronal effect.

BACKGROUND: The effects of bronchial thermoplasty (BT) on smooth muscle (SM) and nerves in small airways are unclear. METHODS: We recruited 15 patients with severe refractory asthma, who received BT treatment. Endobronchial optical-coherence tomography (EB-OCT) was performed at baseline, 3 weeks' follow-up and 2 years' follow-up to evaluate the effect of BT on airway structure. In addition, we divided 12 healthy beagles into a sham group and a BT group, the latter receiving BT on large airways (inner diameter >3 mm) of the lower lobe. The dogs' lung lobes were resected to evaluate histological and neuronal changes of the treated large airways and untreated small airways 12 weeks after BT. RESULTS: Patients receiving BT treatment had significant improvement in Asthma Control Questionnaire (ACQ) scores and significant reduction in asthma exacerbations. EB-OCT results demonstrated a notable increase in inner-airway area (Ai) and decrease in airway wall area percentage (Aw%) in both large (3rd-to 6th-generation) and small (7th-to 9th-generation) airways. Furthermore, the animal study showed a significant reduction in the amount of SM in BT-treated large airways but not in untreated small airways. Protein gene product 9.5 (PGP9.5)-positive nerves and muscarinic receptor 3 (M3 receptor) expression in large and small airways were both markedly decreased throughout the airway wall 12 weeks after BT treatment. CONCLUSIONS: BT significantly reduced nerves, but not SM, in small airways, which might shed light on the mechanism of lung denervation by BT.

Feasibility and Safety of Radiofrequency Ablation Guided by Bronchoscopic Transparenchymal Nodule Access in Canines.

BACKGROUND: The treatment of pulmonary malignancies remains a challenge. The efficacy and safety of bronchoscopic radiofrequency ablation (RFA) for the treatment of lung cancer are not well elucidated. OBJECTIVE: This study aimed to evaluate the feasibility and safety of RFA guided by bronchoscopic transparenchymal nodule access (BTPNA) in vivo. METHODS: In an attempt to determine the parameters of RFA, we first performed RFA in conjunction with automatic saline microperfusion in the lung in vitro with various ablation energy (10, 15, 20, 25, and 30 W) and ablation times (3, 5, 8, and 10 min). The correlation between ablated area and RFA parameter was recorded and analyzed. Further, we conducted a canine study with RFA by BTPNA in vivo, observing the ablation effect and morphological changes in the lung assessed by chest CT and histopathologic examination at various follow-up time points (1 day, n = 3; 30 days, n = 4; 90 days, n = 4). The related complications were also observed and recorded. RESULTS: More ablation energy, but not ablation time, induced a greater range of ablation area in the lung. Ablation energy applied with 15 W for 3 min served as the appropriate setting for pulmonary lesions ≤1 cm. RFA guided by BTPNA was performed in 11 canines with 100% success rate. Inflammation, congestion, and coagulation necrosis were observed after ablation, which could be repaired within 7 days; subsequently, granulation and fibrotic scar tissue developed after 30 days. No procedure-related complication occurred during the operation or in the follow-up periods. CONCLUSION: The novel RFA system and catheter in conjunction with automatic saline microperfusion present a safe and feasible modality in pulmonary parenchyma. RFA guided by BTPNA appears to be well established with an acceptable tolerance; it might further provide therapeutic benefit in pulmonary malignancies.

Postintubation Tracheal Stenosis Evaluated by Endobronchial Optical Coherence Tomography: A Canine Model Study.

BACKGROUND: The predictors and airway morphological changes during the development of postintubation tracheal stenosis (PITS) have not been well elucidated. OBJECTIVES: To elucidate the validation of endobronchial optical coherence tomography (EB-OCT) in assessing the airway morphological changes in PITS. METHODS: We performed oral endotracheal intubation in 12 beagles to establish the PITS model. EB-OCT was performed respectively before modeling and on the 1st, 7th, and 12th day after extubation in 9 canines, and was conducted consecutively in 3 canines during the development of PITS. Histological findings and the thickness and gray-scale value of the tracheal wall assessed by EB-OCT measurements were analyzed and compared. RESULTS: The tracheal wall edema, granulation tissue proliferation, cartilage destruction in PITS, and airway wall thickening detected by EB-OCT were in concordance with the histopathological measurements. The consecutive EB-OCT observation of the airway structure demonstrated the tracheal wall thickness significantly increased from 344.41 ± 44.19 µm before modeling to 796.67 ± 49.75 µm on the 9th day after modeling (p < 0.05). The airway wall gray-scale values assessed by EB-OCT decreased from 111.19 ± 14.71 before modeling to 74.96 ± 4.08 on the 9th day after modeling (p < 0.05). The gray-scale value was negatively correlated with the airway wall thickness (r = -0.945, p = 0.001). CONCLUSION: The EB-OCT imaging, in concordance with the histopathological finding, was validated for assessing the airway morphological changes during the development of PITS. The EB-OCT evaluation of cartilage damage and gray-scale value measurement might help predict the development and prognosis of PITS.

Breathing Hydrogen-Oxygen Mixture Decreases Inspiratory Effort in Patients with Tracheal Stenosis.

BACKGROUND: Hydrogen-oxygen mixture (H2-O2) may reduce airway resistance in patients with acute severe tracheal stenosis, yet data supporting the clinical use of H2-O2 are insufficient. OBJECTIVES: To evaluate the efficacy and safety of breathing H2-O2 in acute severe tracheal stenosis. METHODS: Thirty-five consecutive patients with severe acute tracheal stenosis were recruited in this prospective self-control study. Air, H2-O2 and O2 inhalation was given in 4 consecutive breathing steps: air for 15 min, H2-O2 (6 L per min, H2:O2 = 2: 1) for 15 min, oxygen (3 L per min) for 15 min, and H2-O2 for 120 min. The primary endpoint was inspiratory effort as assessed by diaphragm electromyography (EMGdi); the secondary endpoints were transdiaphragmatic pressure (Pdi), Borg score, vital signs, and impulse oscillometry (IOS). The concentration of H2 in the ambient environment was obtained with 12 monitors. Adverse reactions during the inhalation were recorded. RESULTS: The mean reduction in the EMGdi under H2-O2 was 10.53 ± 6.83%. The EMGdi significantly decreased during 2 H2-O2 inhalation steps (Steps 2 and 4) compared with air (Step 1) and O2 (Step 3) (52.95 ± 15.00 vs. 42.46 ± 13.90 vs. 53.20 ± 14.74 vs. 42.50 ± 14.12% for Steps 1 through 4, p < 0.05). The mean reduction in the Pdi under H2-O2 was 4.77 ± 3.51 cmH2O. Breathing H2-O2 significantly improved the Borg score and resistance parameters of IOS but not vital signs. No adverse reactions occurred. H2 was undetectable in the environment throughout the procedure. CONCLUSIONS: Breathing H2-O2 may reduce the inspiratory effort in patients with acute severe tracheal stenosis and can be used for this purpose safely.

Airway necrosis and granulation tissue formation caused by Rhizopus oryzae leading to severe upper airway obstruction: a case report.

Pulmonary Mucormycosis is a fatal infectious disease with high mortality rate. The occurrence of Mucormycosis is commonly related to the fungal virulence and the host's immunological defenses against pathogens. Mucormycosis infection and granulation tissue formation occurred in the upper airway was rarely reported. This patient was a 60-year-old male with diabetes mellitus, who was admitted to hospital due to progressive cough, sputum and dyspnea. High-resolution computed tomography (HRCT) and bronchoscopy revealed extensive tracheal mucosal necrosis, granulation tissue proliferation, and severe airway stenosis. The mucosal necrotic tissue was induced by the infection of Rhizopus Oryzae, confirmed by metagenomic next-generation sequencing (mNGS) in tissue biopsy. This patient was treated with the placement of a covered stent and local instillation of amphotericin B via bronchoscope. The tracheal mucosal necrosis was markedly alleviated, the symptoms of cough, shortness of breath, as well as exercise tolerance were significantly improved. The placement of airway stent and transbronchial microtube drip of amphotericin B could conduce to rapidly relieve the severe airway obstruction due to Mucormycosis infection.

[The cause and efficacy of benign tracheal stenosis].

OBJECTIVE: To analysis the causes of benign tracheal stenosis and evaluate the curative effect of intraluminal bronchoscopic treatment. METHODS: 158 patients with benign tracheal stenosis in our hospital from September 2005 to September 2012 were collected to retrospectively analysis the causes and clinic features of tracheal stenosis. Interventional treatments through bronchoscopy were used to treat the benign tracheal stenosis and the curative effects were evaluated. RESULTS: 158 cases of benign tracheal stenosis were recruited to our study, 69.6% of them were young and middle-aged. The main causes of benign tracheal stenosis were as follows: secondary to postintubation or tracheotomy in 61.4% (97/158), tuberculosis in 16% (26/158), benign tumor in 5.1% (8/158) and other 27 cases. 94.3% patients improved in symptoms with alleviation immediately after bronchoscopic treatment, the average tracheal diameter increased form (4.22 ± 2.06) mm to (10.16 ± 2.99) mm (t = 21.48, P < 0.01), dyspnea index decreased from 2.29 ± 0.75 to 0.63 ± 0.67 (t = 19.85, P < 0.01). The recurrence rate in 1 and 3 month after interventional treatment were 38.3% and 26.8%, respectively. CONCLUSION: The cases of benign tracheal stenosis were increasing year by year. The most common cause of benign tracheal stenosis was postintubation and tracheotomy. Interventional treatments through bronchoscopy is effective in treating benign tracheal stenosis, but repeated interventional procedures may be required to maintain the favorable long-term effects.

Endobronchial optical coherence tomography or computed tomography for evaluating progression of bronchiectasis.

Background: The early radiological signs of progression in bronchiectasis remain unclear. The objective of the present study was to compare endobronchial optical coherence tomography (EB-OCT) and chest computed tomography (CT) for the evaluation of radiological progression of bronchiectasis via stratification of the presence (TW+) or absence (TW-) of thickened-walled bronchioles surrounding dilated bronchi in patients with bronchiectasis based on CT, and determine the risk factors. Methods: In this prospective cohort study, we performed both chest CT and EB-OCT at baseline and 5-year follow-up, to compare changes in airway calibre metrics. We evaluated bacterial microbiology, sputum matrix metalloproteinase-9 levels and free neutrophil elastase activity at baseline. We compared clinical characteristics and airway calibre metrics between the TW+ and TW- groups. We ascertained radiological progression at 5 years via CT and EB-OCT. Results: We recruited 75 patients between 2014 and 2017. At baseline, EB-OCT metrics (mean luminal diameter (p=0.017), inner airway area (p=0.005) and airway wall area (p=0.009) of seventh- to ninth-generation bronchioles) were significantly greater in the TW+ group than in the TW-group. Meanwhile, EB-OCT did not reveal bronchiole dilatation (compared with the same segment of normal bronchioles) surrounding nondilated bronchi on CT in the TW- group. At 5 years, 53.1% of patients in the TW+ group progressed to have bronchiectasis measured with EB-OCT, compared with only 3.3% in TW- group (p<0.05). 34 patients in the TW+ group demonstrated marked dilatation of medium-sized and small airways. Higher baseline neutrophil elastase activity and TW+ bronchioles on CT predicted progression of bronchiectasis. Conclusion: Thickened-walled bronchioles surrounding the dilated bronchi, identified with EB-OCT, indicates progression of bronchiectasis.

Multiple Lung Cavity Lesions, Thoracic Wall Abscess and Vertebral Destruction Caused by Streptococcus constellatus Infection: A Case Report.

Disseminated infection caused by Streptococcus constellatus was seldom occurred. We reported a case of Streptococcus constellatus infection, presenting as multiple pulmonary cavities, thoracic wall abscess and vertebral destruction. The 37-year-old male had recurrent fever, chest wall swelling and pain, and lower limb numbness, he had weak physical condition and previously suffered from poorly controlled diabetes and severe periodontal disease for 3 years. Definite diagnosis of Streptococcus constellatus infection was made by metagenomic next­generation sequencing (mNGS) in abscess drainage fluid. Systemic antibiotics and thoracic wall drainage were given, and the pulmonary cavity and the thoracic intermuscular abscess were significantly decreased. Few to no study reported the disseminated infection (pulmonary cavities, thoracic wall abscess and vertebral destruction) caused by Streptococcus constellatus. This case report highlighted the importance of mNGS for accurate diagnosis, as well as the timely drainage and antibiotics for effective treatment of Streptococcus constellatus infection.

Airway morphological abnormalities of bronchiolitis assessed by endobronchial optical coherence tomography.

BACKGROUND: A few studies have reported the medium-sized and small airway morphological abnormalities of bronchiolitis. Whether spirometry or impulse oscillometry (IOS) is correlated with airway remodeling of bronchiolitis remains unclear. OBJECTIVES: Aiming to demonstrate the airway morphological abnormalities of bronchiolitis obliterans (BO) and diffuse panbronchiolitis (DPB) assessed by endobronchial optical coherence tomography (EB-OCT), and elucidate whether spirometric and IOS parameters have correlation with the airway remodeling of bronchiolitis. METHODS: We recruited 18 patients with bronchiolitis (BO, n = 9; DPB, n = 9) and 17 control subjects. Assessments of clinical features, St. George's respiratory questionnaire (SGRQ), chest computed tomography (CT), spirometry, IOS, and EB-OCT were performed in all enrolled subjects. The correlation between EB-OCT and lung function parameters was studied and analyzed. RESULTS: The magnitude of abnormalities of spirometric and IOS parameters was significantly greater in patients with bronchiolitis than that in control subjects (p < 0.05). Patients with BO had notably lower forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, maximal mid-expiratory flow (MMEF)% pred and higher resonant frequency (Fres), and area of reactance (AX) than those with DPB (p < 0.05). The EB-OCT measurement among patients with bronchiolitis and between the bronchus in the left and the right lung demonstrated a heterogeneous distribution of airway calibers, presenting a high intra- and inter-individual variability. Patients with bronchiolitis had notably greater airway wall area (p < 0.05) compared with control, while BO presented greater magnitude of airway abnormalities than DPB. Fres and the difference in airway resistance at 5 and 20 Hz (R5-R20) correlated negatively with medium-sized and small airway inner area, and correlated positively with airway wall area (p < 0.05), whose correlation coefficients were higher than those of spirometric parameters. CONCLUSION: Bronchiolitis, BO and DPB, manifested a heterogeneous distribution of airway calibers with significant intra- and inter-individual variability. IOS parameters, rather than spirometry, correlated better with medium-sized and small airway remodeling in bronchiolitis assessed by EB-OCT measurement.

Autologous Airway Basal Cell Transplantation Alleviates Airway Epithelium Defect in Recurrent Benign Tracheal Stenosis.

BACKGROUND: Airway epithelium defects are a hallmark of recurrent benign tracheal stenosis (RBTS). Reconstructing an intact airway epithelium is of great importance in airway homeostasis and epithelial wound healing and has great potential for treating tracheal stenosis. METHODS: An experimental study was conducted in canines to explore the therapeutic effect of autologous basal cell transplantation in restoring airway homeostasis. First, airway mucosae from human patients with recurrent tracheal stenosis were analyzed by single-cell RNA sequencing. Canines were then randomly divided into tracheal stenosis, Stent, Stent + Cells, and Stent + Cells + Biogel groups. Autologous airway basal cells of canines in the Stent + Cells and Stent + Cells + Biogel groups were transplanted onto the stenotic airway after modeling. A biogel was coated on the airway prior to basal cell transplantation in the Stent + Cells + Biogel group. After bronchoscopic treatments, canines were followed up for 16 weeks. RESULTS: Single-cell RNA sequencing demonstrated packed airway basal cells and an absence of normal airway epithelial cells in patients with RBTS. Autologous airway basal cell transplantation, together with biogel coating, was successfully performed in the canine model. Follow-up observation indicated that survival time in the Stent + Cells + Biogel group was significantly prolonged, with a higher (100%) survival rate compared with the other groups. In terms of pathological and bronchoscopic findings, canines that received autologous basal cell transplantation showed a reduction in granulation hyperplasia as well as airway re-epithelialization with functionally mature epithelial cells. CONCLUSIONS: Autologous airway basal cell transplantation might serve as a novel regenerative therapy for airway re-epithelialization and inhibit recurrent granulation hyperplasia in benign tracheal stenosis.

Self-expanding covered metallic stents as a transition to silicone stent implantation in management of severe post-tuberculosis bronchial stenosis.

BACKGROUND AND AIMS: Post-tuberculosis bronchial stenosis (PTBS) is one of the most common complications of tracheobronchial tuberculosis. Silicone stent serves as a major treatment for maintaining airway patency. However, silicone stent placement remains a large challenge in patients with severe cicatricial PTBS. Our objective was to evaluate the efficacy and safety of covered, self-expanding, metallic stents (SEMSs) as a transition to silicone stent implantation for treating severe PTBS. METHODS: We retrospectively reviewed the data of patients with severe PTBS who received airway stenting in the First Affiliated Hospital of Guangdong Medical University between September 2015 and May 2019. The types of the stent, intervention procedures, bronchoscopic findings, clinical outcomes and related complications were collected and analyzed. RESULTS: Fifty-eight cases with severe PTBS were included in this study. Thirteen (22.4%) of the patients received bronchial silicone stent implantation immediately after dilations. For the remaining 45 (77.6%) patients, silicone stents could not be deployed after dilations and SEMSs implantation was implemented as a bridge to silicone stenting. The SEMSs were placed for an interval of 28.4 ± 11.1 days. All of the silicone stents were inserted successfully following the removal of SEMSs. No SEMS-related complication occurred. The subgroup analysis showed that patients who received transitional SEMSs had less luminal caliber but fewer transbronchial dilations before silicone stent implantation (p < 0.05). CONCLUSION: Covered SEMS placement as a transition to silicone stenting could serve as a feasible procedure to reduce complications and improve the success rate of silicone stent implantation in patients with severe PTBS.The reviews of this paper are available via the supplemental material section.

Hybrid stenting with silicone Y stents and metallic stents in the management of severe malignant airway stenosis and fistulas.

BACKGROUND: Airway stenting is frequently used in the palliative treatment of patients with advanced tumor-induced airway stenosis and fistulas. However, there is paucity of studies regarding the use of airway stents in restoring patency. The aim of the study was to assess the efficacy and safety of hybrid silicon Y stents and covered self-expanding metal stents (SEMS) and in reestablishing patency in airway stenoses and fistulas. METHODS: This retrospective study included 31 patients between January 2016 to December 2019 with inoperable complex malignant airway stenoses and fistulas, managed with Silicone Y stents, and covered SEMS. The clinical details, clinical outcomes and complications up to 6 months were extracted from medical records. The improvement of performance was assessed based on modified British Medical Research Council (mMRC) dyspnea scores (t=6.892, P<0.001), Karnofsky Performance Scores (KPS) (t=-11.653, P<0.001), and performance status (PS) (t=3.503, P<0.001). RESULT: A total of 31 silicon Y stents and 35 covered SEMSs were inserted. Of the 31 patients (M:F 20:11; age: 54.64±9.57), 25/31 (80.6%) experienced immediate relief of symptoms following stent placement. Patients' mMRC dyspnea scores, KPS, and PS showed significant improvement following stenting. The mean duration of stent placement was 146.3±47.7 days, and 17/31 (55%) patients were alive at 6 months. No major complications related to hybrid stenting were observed during the follow-up period. CONCLUSIONS: Hybrid stenting is a feasible and safe palliative treatment for malignant airway stenosis and fistulas to improve quality of life and can be performed without major complications.

Evaluation of the Normal Airway Morphology Using Optical Coherence Tomography.

BACKGROUND: The anatomic location of small airways, the distribution of airway cartilage, and their correlation with ageing have not been well elucidated. The objective of this article was to explore the morphologic characteristics of small airways in vivo, and how airway structural changes correlate with age using endobronchial optical coherence tomography (EB-OCT). METHODS: We recruited 112 subjects with peripheral pulmonary nodules. Participants underwent CT scan, spirometry, and EB-OCT measurements. We measured the airway internal diameter, the inner area (Ai), the airway wall area percentage (Aw%), and the thickness of airway cartilage. EB-OCT airway structural characteristics at different age intervals were analyzed, and the association between airway morphology and age was evaluated. RESULTS: Of the small airways, 47.3% originated from the seventh generation of bronchi. Cartilage was uniformly present in the third to sixth generation of bronchi, despite a decreasing proportion of cartilage from the seventh to ninth generation of bronchi (92.4%, 54.5%, and 26.8%, respectively). The thickness of airway cartilage progressively decreased with older age. In subjects 40 to 54 years of age, Ai from the third to sixth generation correlated positively with age (r = 0.577, P < .001). Both Ai from the third to sixth generation and Ai from the seventh to ninth generation correlated negatively with age in subjects 55 to 69 years of age (r = -0.374, P = .021 and r = -0.410, P = .011). Aw% from the third to sixth generation and Aw% from the seventh to ninth generation did not correlate significantly with age. CONCLUSIONS: Small airways are mainly located at the seventh generation, where cartilaginous structures are present despite reduced distribution in more distal airways, and the thickness decreased in older age. Reduction in luminal area of medium-to-small airways might be the morphologic changes associated with ageing (ie, > 55 years of age).

Performance evaluation of detecting circulating tumor cells and tumor cells in bronchoalveolar lavage fluid in diagnosis of peripheral lung cancer.

BACKGROUND: To evaluate the diagnostic performances of detecting circulating tumor cells (CTCs) and tumor cells in bronchoalveolar lavage fluid (BALF) for peripheral lung cancer. METHODS: A total of 247 patients with lung cancer and 70 cases with benign lung disease were recruited in this study. Peripheral blood and BALF samples were collected, in which the tumor cells were enriched by negative immunomagnetic selection and detected by fluorescence in situ hybridization (FISH) of chromosome enumeration probe 8 (CEP8). The levels of tumor-associated markers (e.g., CEA, CA125, and NSE) in peripheral blood plasma were measured by using electrochemiluminescence. RESULTS: The numbers of CTCs detected in peripheral blood were significantly higher in patients with lung cancer than those with benign lung disease (5.78±0.57 vs. 1.13±0.39, Z=-8.64, P<0.01). Similarly, tumor cells count in BALF of malignancy were higher than that of benign lesions (6.76±0.89 vs. 0.89±0.23, Z=-6.254, P<0.01). However, as for patients with lung cancer and benign lung disease, the numbers of tumor cells in peripheral blood were comparable with those in BALF (both P>0.05). Detecting CTCs and tumor cells in BALF had similar areas under curves (AUC =0.871 and 0.963, respectively; P>0.05) in discriminating benign lesions from lung cancer (sensitivity 83.8% and 92.6%, specificity 86.5% and 99.9%, respectively), both of which were larger than those of NSE, CEA, and CA125 (AUC =0.564, 0.512 and 0.554, respectively; all P<0.05). The diagnostic performances of discriminating benign lesions and lung cancer in BALF and peripheral blood were both in concordance with that of histopathology (kappa values 0.662 and 0.569, respectively; both P<0.001). CONCLUSIONS: Detecting tumor cells in peripheral blood and BALF may sensitive to identify benign and malignant peripheral lung lesions and be of value for early diagnosis of lung cancer.