Virtual bronchoscopy: clinical applications and limitations

Virtual bronchoscopy (VB) is a term that describes a variety of software-based three-dimensional visualizations created from noninvasive medical imaging methods such as CT or MRI scans, with the goal of creating results similar to minimally invasive bronchoscopy procedures of the trachea and upper airways. This technique offers a detailed, noninvasive view of the airways, with reduced risk of infection or perforation, and facilitates preoperative planning for airway interventions that would otherwise not be possible. It is unlikely that VB will replace fiberoptic bronchoscopy; however, as VB techniques become more sophisticated and as sufficient computing and imaging power become more readily available, noninvasive visualization of the airways will play an important and useful role in the evaluation of airway diseases in well defined clinical situations.     

Hybrid 3D visualization of the chest and virtual endoscopy of the tracheobronchial system: possibilities and limitations of clinical application

OBJECTIVE: A hybrid rendering method which combines a color-coded surface rendering method and a volume rendering method is described, which enables virtual endoscopic examinations using different representation models. MATERIALS AND METHODS: 14 patients with malignancies of the lung and mediastinum (n=11) and lung transplantation (n=3) underwent thin-section spiral computed tomography. The tracheobronchial system and anatomical and pathological features of the chest were segmented using an interactive threshold interval volume-growing segmentation algorithm and visualized with a color-coded surface rendering method. The structures of interest were then superimposed on a volume rendering of the other thoracic structures. For the virtual endoscopy of the tracheobronchial system, a shaded-surface model without color coding, a transparent color-coded shaded-surface model and a triangle-surface model were tested and compared. RESULTS: The hybrid rendering technique exploit the advantages of both rendering methods, provides an excellent overview of the tracheobronchial system and allows a clear depiction of the complex spatial relationships of anatomical and pathological features. Virtual bronchoscopy with a transparent color-coded shaded-surface model allows both a simultaneous visualization of an airway, an airway lesion and mediastinal structures and a quantitative assessment of the spatial relationship between these structures, thus improving confidence in the diagnosis of endotracheal and endobronchial diseases. CONCLUSIONS: Hybrid rendering and virtual endoscopy obviate the need for time consuming detailed analysis and presentation of axial source images. Virtual bronchoscopy with a transparent color-coded shaded-surface model offers a practical alternative to fiberoptic bronchoscopy and is particularly promising for patients in whom fiberoptic bronchoscopy is not feasible, contraindicated or refused. Furthermore, it can be used as a complementary procedure to fiberoptic bronchoscopy in evaluating airway stenosis and guiding bronchoscopic biopsy, surgical intervention and palliative therapy and is likely to be increasingly accepted as a screening method for people with suspected endobronchial malignancy and as control examination in the aftercare of patients with malignant diseases.     

Möglichkeiten der Bronchoskopie in der Onkologie

Bronchoscopy plays a significant role in pulmonary oncology. Due to technological advances, such as the introduction of autofluorescence bronchoscopy, navigation techniques and endobronchial ultrasound, bronchoscopy has become the most important tool in the diagnostics and mediastinal staging of lung cancer. Furthermore, bronchoscopy is of great importance in the treatment of minimally invasive early lung cancer as well as of locally advanced tumors. Tumor-related hemoptysis, malignant central airway obstruction and tracheoesophageal fistula are indications for an urgent bronchoscopic intervention. Various endoscopic techniques are available for the management of these accompanying complications of lung cancer.     

Endobronchial Ultrasonography: Current Status and Future Directions

Endobronchial ultrasonography (EBUS) has emerged as a new diagnostic tool that allows the bronchoscopist to see beyond the airway. The radial probe EBUS was first introduced to evaluate the airway structure, which has been shown to be useful for identifying the extent of tumor invasion in the central airway. With advance in technology, smaller radial probes are now available that are capable of visualizing peripheral lung nodules. EBUS is also used as a tool to assist in a biopsy in respiratory diseases. The radial probe EBUS–guided transbronchial needle aspiration (TBNA) increases the yield of TBNA of mediastinal processes. By the use of the ultra-miniature probe EBUS along with the guide sheath, peripheral lung lesions can be accessed without the exposure to radiation. However, it is still not a real-time procedure with target visualization. The newest development is the convex probe EBUS (CP-EBUS) with a curvilinear electronic transducer on the tip of a flexible bronchovideoscope. CP-EBUS allows real-time EBUS-guided TBNA. Although the main indication for EBUS-TBNA is lymph node staging, it can also be used for diagnosis of intrapulmonary tumors, of unknown hilar and/or mediastinal lymphadenopathy, and of mediastinal tumors. To date, there are no reports of complications related to EBUS-guided TBNA. It is a novel approach that has a good diagnostic yield with excellent potential in assisting safe and accurate diagnostic interventional bronchoscopy. The aim of this review is to highlight the current status of the different EBUS techniques available and to discuss the future direction of EBUS.     

内镜技术发展对肺癌诊断的影响

近年来,一些新技术在支气管镜下的应用得以实现,例如支气管内超声（EBUS）技术、自动荧光支气管镜（AFB）技术、电磁导航支气管镜技术（ENB）、荧光共聚焦显微镜（FCFM）技术及光干涉断层扫描（OCT）技术等,均从不同角度和层面解决了以往传统技术手段存在的缺陷。虽然目前这些技术手段还有待进一步完善和临床验证,但其必然会对肺癌的诊断和治疗产生巨大的影响。     

Virtual bronchoscopy: comparison of different surface rendering models

The aim of this study was to compare different representation models of surface-rendered virtual bronchoscopy. 10 consecutive patients with inoperable primary lung tumors underwent thin-section spiral computed tomography. The structures of interest, the tracheobronchial system and anatomical and pathological thoracic structures were segmented using an interactive threshold interval volume-growing segmentation algorithm and visualized with the aid of a color-coded surface rendering method. For virtual bronchoscopy, the tracheobronchial system was visualized using a triangle-surface rendering model, a shaded-surface rendering model and a transparent shaded-surface rendering model. The triangle-surface rendering model allowed optimum detailed spatial representation of the dimensions of extraluminal anatomical and pathological mediastinal structures. As the lumen of the tracheobronchial system was less well defined, the rendering model was of limited use for depiction of the airway surface. The shaded-surface rendering model facilitated an optimum assessment of the airway surface, but the mediastinal structures could not be depicted. The transparent shaded-surface rendering model provides simultaneous adequate to optimum visualization and assessment of the intraluminal airway surface and the extraluminal mediastinal structures as well as a quantitative assessment of the spatial relationship between these structures. Fast data acquisition with a multi-slice detector spiral computed tomography scanner and the use of virtual bronchoscopy with the transparent shaded-surface rendering model obviate the need for time consuming detailed analysis and presentation of axial source images by providing improved the diagnostic imaging of endotracheal and endobronchial diseases and offering a useful alternative to fiberoptic bronchoscopy.     

Bronchoscopic insertion of Gianturco stents for the palliation of malignant lung disease: 10 year experience

Malignant large airway obstruction is life threatening and may not be amenable to urgent radiotherapy. Palliative airway stenting is difficult and traditionally carried out under general anaesthesia and fluoroscopy. We have shown that self expanding Gianturco metal stents can be placed under local anaesthesia using fibreoptic bronchoscopy and direct vision for the treatment of malignant airway tumours, and report our 10 year experience. All referrals for stenting referred to our unit between 1990 and 1999 were included, looking for histological type, number and site of stents, complications of the procedure, other interventions, and survival. One hundred and sixty two patients (average age 64 years, (range 21-89)) had 307 stents inserted during 167 procedures (144 primary lung tumours, 18 secondary malignancy). There were no operative deaths, but three patients developed a pneumothorax, one requiring intercostal drain insertion. Average survival following stent insertion was less for primary lung cancer than for secondary disease (103 vs. 431 days, P<0.001). There were no excess complications in a subgroup of 64 patients treated locally by oncologists, even when stenting was the primary procedure. This technique is useful in palliating life threatening airway obstruction, particularly for secondary cancer, and can be used in any centre undertaking fibreoptic bronchoscopy.     

Endobronchial brachytherapy in combination with external beam irradiation in obstructing malignant bronchial tumors

Endobronchial brachytherapy is commonly used in the palliative management of malignant airway obstructions. In the present study, we describe the results of brachytherapy (mean dose of 18 Gy), used in combination with external beam irradiation (mean dose of 50 Gy) in 30 patients who had primary bronchogenic carcinoma of the lung. The extent of airway obstruction was determined according to symptoms and by bronchoscopy. We found symptoms improved in nearly 37% of patients and 21 of 30 patients (70%), evaluated with bronchoscopy, showed a response when evaluated 3 to 6 months after brachytherapy. This endobronchial technique appeared to be a well-tolerated procedure with a low rate of acute toxicity. The immediate complication rate was 13%, during the follow-up 3 deaths were related to treatment, of which 2 were fatal haemoptysis (12 and 18 months after irradiation). We conclude that the combination of endobronchial brachytherapy with external beam irradiation may be useful and needs further comparisons with other irradiation procedures.     

Interventionelle Therapie

Patients with lung cancer often have bulky endobronchial disease, endobronchial extension, or airway compression. Many endobronchial treatment modalities are available to supplement traditional therapies for advanced lung cancer. Since the early 1980s, technical advances in interventional techniques have enhanced symptom-free survival and quality of life for patients with lung cancer. Although interventional procedures are not definitive therapies, they often relieve the strangling sensation produced by airway occlusion. For patients with respiratory symptoms associated with their disease, these interventions provide symptom palliation and improved quality of life. The authors review the use of several endobronchial treatment modalities including rigid and flexible bronchoscopy, laser therapy, endobronchial prosthesis, and photodynamic therapy.     

被膜金属支架在气道瘘治疗中的应用研究

背景与目的气道瘘包括食管气管瘘、支气管胸膜瘘和气管纵隔瘘,临床治疗较为棘手。本文旨在探讨被膜金属支架封堵气道瘘的疗效和安全性。方法回顾性分析32例食管气管瘘、5例支气管胸膜瘘和1例气管纵隔瘘患者在气管镜和/或X线透视下放置被膜金属支架。原发病为食管肿瘤26例,肺癌11例,甲状腺癌1例。结果 38例患者共有46个瘘口,口径0.5cm-7.0cm。放置Z型气管被膜金属支架40枚(其中Y形24枚,L形8枚和I形8枚)。食管放置被膜金属支架24枚。46个瘘口封堵疗效:治愈2例(4.3%),临床完全缓解28例(60.9%),部分缓解11例(23.9%),无效5例(10.9%),有效率为89.1%,中位生存时间为5个月。结论被膜金属支架能有效封堵食管气管瘘、支气管胸膜瘘和气管纵隔瘘。应首选气管支架封堵ERF,无效的患者可同时放置食管支架。分叉型气管支架尤其适于隆突周围瘘口。     

Comparison of the autofluorescence bronchoscope and the white light bronchoscope in airway examination

Background and Objective: The sensitivity and accuracy of white light bronchoscopy (WLB) in airway examination are low. Autofluorescence bronchoscope (AFB) can determine early lesions in bronchial mucosa more sensitively, but it has seldom performed in China. To assess the clinical value of the AFB in airway examination, we compared the sensitivity and specificity of the AFB and WLB in detecting cancer of the airway mucosa. Methods: Between September 2009 and May 2010, bronchoscope examinations using both t...     

R-EBUS、LungPro导航支气管镜联合快速现场细胞学评估在周围型肺结节诊断中的应用价值比较

背景与目的：经气管肺部病变活检具有并发症低的优点,但对于周围型肺结节,传统支气管镜的诊断率极低。目前常用的提高周围型肺结节诊断率的导航技术在在诊断率及安全性方面的差异还不十分清楚,比较径向支气管内超声（radial endobronchial ultrasound,R-EBUS）引导支气管镜、LungPro导航支气管镜、R-EBUS联合LungPro导航支气管镜对周围型肺结节的诊断率和安全性的差异并探讨快速现场细胞学评估（cytological rapid on-site evaluation,C-ROSE）在诊断中的价值。方法：将2018年11月—2019年4月在昆明医科大学第三附属医院行气管镜检查且符合纳入及排除标准的255例周围型肺结节患者随机分为3组：R-EBUS组（85例）、LungPro导航组（85例）和R-EBUS+LungPro导航组（85例）,3组均行C-ROSE,比较3组之间的导航时间、手术操作时间、出血量、诊断率及并发症的发生率。结果：LungPro导航组和R-EBUS+LungPro导航组诊断率分别为85.9%（73/85）和87.1%（74/85）,显著高于R-EBUS组的诊断率［72.9%（62/85）］（P＜0.05）,但LungPro导航组和R-EBUS+LungPro导航组之间差异无统计学意义（P＞0.05）。R-EBUS组病灶导航时间为（11.34±12.95）min,手术时间为（28.37±1.98）min,显著长于LungPro导航组［（3.72±0.71）min,（19.35±1.53） min］和R-EBUS+LungPro导航组［（6.12±1.14）min,（21.00±1.97）min］（P＜0.001）,LungPro导航组导航时间及手术时间均显著低于R-EBUS+LungPro组（P＜0.001）。R-EBUS组出血量为（4.18±1.42）mL,LungPro导航组为（4.26±1.00）mL,R-EBUS+LungPro导航组为（4.41±1.19）mL,3组间差异无统计学意义（P＞0.05）。R-EBUS组发生气胸2例（2.3%,2/85）,LungPro导航组发生气胸2例（2.3%,2/85）,胸膜反应1例（1.2%,1/85）,R-EBUS+LungPro导航组发生气胸1例（1.2%,1/85）,未见其他严重并发症。C-ROSE评估与病理学检查结果诊断符合率为83.9%,灵敏度为83.7%、特异度为84.3%、阳性预测值87.9%,阴性预测值为79.1%。结论： LungPro导航可精确抵达病灶取得病理组织,有较高的诊断率,且有导航及手术时间短、安全、并发症少等优点,与C-ROSE结合可提高取样质量,减少活检、穿刺次数从而减少并发症发生。     

Interventional endoscopic treatment

Interventional bronchoscopy has evolved as an integral part of lung-cancer treatment but it is not always used to its full potential. The different methods can provide immediate relief of dyspnea and haemoptysis. Bleeding from central airway tumours can be stopped by coagulation preferably with the argon plasma coagulator. In cases of intraluminally growing tumour masses removal of the malignant tissue is accomplished with the Nd-YAG laser, electrocautery, argon plasma coagulation, cryotherapy or photodynamic therapy. Intramural tumour growth is most efficiently treated with high dose-rate endobronchial brachytherapy. Extrinsic compression or airway wall destruction require the placement of an airway stent. All methods can be combined and complement other palliation methods such as radiation or chemotherapy.     

Primary Tracheal Lymphoma Causing Respiratory Failure

Lymphomatous involvement of the airway causing stridor is a rare but frightening presentation of an eminently treatable condition. We describe a 24-year-old woman with tracheal non-Hodgkin lymphoma who was initially diagnosed with asthma, but subsequently presented with near-fatal acute upper airway obstruction because of a tracheal Anaplastic Lymphoma Kinase (ALK)+ anaplastic T-cell lymphoma. The obstructing tumor was extricated by means of rigid bronchoscopy. After six cycles of Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone chemotherapy, the patient went into complete clinical remission. A high index of suspicion in patients with dyspnoea and wheeze unresponsive to bronchodilators is crucial in early diagnosis of tracheal tumors.     

A prospective comparison of fiberoptic transbronchial needle aspiration and bronchial biopsy for bronchoscopically visible lung carcinoma.

BACKGROUND: Fiberoptic bronchoscopy is the most common modality used to diagnose endobronchial carcinoma. The authors prospectively compared the sensitivity of endobronchial needle aspiration (EBNA) and immediate cytologic assessment with bronchial biopsy and bronchial washing in the diagnosis of endobronchial malignancy. METHODS: A prospective trial comparing the sensitivity of EBNA, bronchial biopsy, and bronchial washings during fiberoptic bronchoscopy for endobronchially visible lung tumor was conducted. The authors enrolled 65 consecutive patients with endobronchial abnormalities identified during bronchoscopy. All patients in the study underwent fiberoptic bronchoscopy that included EBNA, bronchial biopsy, and bronchial wash. The sensitivities of the individual techniques were compared. The sensitivities of bronchoscopy were also prospectively compared when multiple sampling techniques were employed. RESULTS: Malignancy was present in 57 of 65 study patients. Cancer was diagnosed in 47 patients by EBNA, 42 patients by bronchial biopsy, and 36 patients by bronchial washing. The sensitivity of a strategy employing bronchial biopsy and bronchial washings was 0.82 (95% CI, 0.70-0.90). The addition of EBNA to bronchial biopsy and bronchial washings significantly increased the sensitivity to 0.95 (95% CI, 0.85-0.98; McNemar P = 0.02). Subset analysis revealed that this strategy was especially useful in cases in which lesions were submucosal or causing extrinsic compression. CONCLUSIONS: There is a modest increase in the sensitivity of fiberoptic bronchoscopy in diagnosing endobronchial cancer with the addition of EBNA to bronchial biopsy and bronchial washings, especially for patients with submucosal abnormalities. Collection of EBNA, followed by biopsy and washings only if immediate interpretation of EBNA is negative or inadequate, may be the most effective bronchoscopy strategy for evaluating visible endobronchial abnormalities.     

支气管镜介入治疗肺肉瘤

背景与目的肺肉瘤为发生于肺部少见的软组织恶性肿瘤,常规治疗首选手术。本研究旨在探讨采用支气管镜介入治疗的效果。方法回顾性分析2008年11月-2014年7月我院收治的16例肺肉瘤患者,平均年龄（53.1±5.4）岁。所有患者首次治疗均选用全凭静脉麻醉下硬质气管镜检查,发现肿瘤后行支气管镜介入治疗。再次检查时行电子支气管镜检查。结果16例患者中肉瘤样癌10例,纤维肉瘤和肉瘤各2例,纤维粘液性肉瘤和梭性细胞型滑膜肉瘤各1例。周围型11例（占68.8%）,主要位于右上叶和左下叶肺内;中央型5例（31.2%）。位于肺内者以混合型多见（9/11,82%）,原发性较多（9/11,82%）;而位于大气道者以管内型多见（9/16,56%）,转移性较多（11/16,69%）。支气管镜介入治疗后4例全肺不张均缓解,7例肺叶不张3例完全缓解,部分缓解和无效各2例。患者气道阻塞、卡氏体力状态（Karnofsky performance status, KPS）和气促评分均有明显改善。结论支气管镜介入治疗能快速、有效地清除气道内肿瘤,缓解气道梗阻,改善症状。     

Comparison of Virtual and Fiberoptic Bronchoscopy in the Management of Airway Stenosis

Noninvasive imaging methods can be valuable tools for diagnosing thoracic diseases, especially malignancies. The aim of this study was to compare the effectiveness of conventional and virtual bronchoscopy in the follow-up of patients with large airway stenosis. Twenty-three consecutive patients with stenoses of the trachea and/or the main bronchi were enrolled in this prospective observer study. The causes of stenosis included malignant or benign tumours, goiter, and postintubation stenoses. Patients were evaluated before and after treatment (which included mechanical dilation, laser photocoagulation, stent implantation, radiotherapy, chemotherapy, and surgical resection). The mean time between baseline and follow-up endoscopy was 140 days. No significant differences were observed between the estimated and measured data from bronchofibroscopy and virtual bronchoscopy. Exact measurement of stenoses was performed with virtual bronchoscopy.     

原发性气管肿瘤的诊断及外科治疗

原发性气管肿瘤约占呼吸系统肿瘤1%,约有20余种类型.但由于气管本身解剖及功能的特殊性,气管肿瘤早期诊断困难,极易引起误诊,误诊率可达83.3%,有误诊长达10年的报道.减少误诊、防止漏诊、提高早期诊断率的关键措施在于提高对原发气管肿瘤的认识,主要诊断手段包括胸部CT及纤维支气管镜检查.外科治疗是气管肿瘤治疗的重要组成部分,主要包括:气管开窗肿物摘除术,气管局部切除缝合术,气管环行切除对端吻合术,隆突切除吻合术.麻醉和呼吸道管理是气管外科手术成功的重要保证,要根据肿瘤的不同情况采用不同的麻醉方式,强调麻醉医师参与术前讨论的重要性.外科术后的并发症主要包括:吻合口瘘,吻合口大血管瘘,吻合口狭窄及肉芽肿形成,肺部感染及肺不张.

Abstract：

Primary airway tumors are accounted about 1 % of respiratory tumors and have above 20 types. However, due to particularity of the anatomy and function of airway, early diagnosis of the primary air tumors is difficult and the rate of misdiagnosis can reach 83.3 %. To reduce the rate of misdiagnosis, the key measurements of diagnosis are recognization of primary airway tumors, and the main methods include chest computed tomography (CT) and fiberoptic bronchoscopy examination. Surgical treatment is an important part,it includes tumor excision by airway fenestration, the part excision of airway and suture, the resection of airway tumor by its margin and anastomosis, and carinal resection and anastomosis. Anesthesia and the management of respiratory airway are important guarantees for the successful operation. According to the difference of the tumors, the suitable method of anesthesia should be choiced. It is emphasized for anesthesiologist to participate in the preoperative discussion. The postoperative complications include the anastomotic fistula, the anastomotic fistula communication with large vessel, the anastomotic stenosis and granuloma formation, and the pulmonary infection and atelectasis.     

Improving the specificity of fluorescence bronchoscopy for the analysis of neoplastic lesions of the bronchial tree by combination with optical spectroscopy: preliminary communication

Detection of malignancies of the bronchial tree in an early stage, such as carcinoma in situ (CIS), augments the cure rate considerably. It has been shown that the sensitivity of autofluorescence bronchoscopy is better than white light bronchoscopy for the detection of CIS and dysplastic lesions. Autofluorescence bronchoscopy is, however, characterized by a low specificity with a high rate of false positive findings. In the present paper we propose to combine autofluorescence bronchoscopy with optical spectroscopy to improve the specificity of autofluorescence imaging, while maintaining the high sensitivity. Standard autofluorescence bronchoscopy was used to find suspect lesions in the upper bronchial tree, and these lesions were subsequently characterized spectroscopically using a custom made fiberoptic probe. Autofluorescence spectra of the lesions as well as reflectance spectra were measured. We will show in this preliminary report that the addition of either of these spectroscopic techniques decreases the rate of false positives findings, with the best results obtained when both spectroscopic modalities are combined.     

CT仿真支气管内窥镜在中央型肺癌诊断中的应用

目的：评价螺旋CT仿真支气管内窥镜（CTVB）在中央型肺癌诊断中的作用。方法对45例经纤维支气管检查和病理证实的气管、支气管肿瘤患者进行CT仿真内窥镜检查，包括中央型肺癌33例、肺癌术后8例，肺癌放疗后2例及气恶性肿瘤2例。用新型螺旋CT机对患者进行扫描后，将数据建成CTVB图像进行分析，并与纤维支气管镜进行对照，24例与病理标本进行对照。结果CTV显示了100％的段以上支气管和80％以上的亚段支气管，肿瘤呈块状或结节状，引起管腔狭窄或闭塞。肺癌术后正常的支气管残端呈光滑的盲端，肿瘤复发呈结节状突出，与纤维支气管镜所见基本一致，肺癌放疗后支气管腔轻度凹凸不平及管腔狭窄，结论CTVB是一种新的无创性观察气管、支气管腔的方法、酷似纤维支气管镜所见，结合其他三维重建功能，能同时显示管壁的厚度和肿瘤向管腔外侵犯的范围，但与纤维支气管镜相比，不易观察支气管黏膜的表浅病变且不能活检。