Usefulness of ultrathin bronchoscopy in diagnosis of lung cancer

Ultrathin bronchoscopy for diagnosing peripheral pulmonary lesions

Bronchoscopes are continuously improving. Increasingly, thinner bronchoscopes with larger working channels and better imaging quality are becoming available for clinical use. Concurrently, useful ancillary devices have been developed, such as radial probe endobronchial ultrasound (rEBUS) and navigation devices. Randomized studies have demonstrated the diagnostic superiority of ultrathin bronchoscopy over thin bronchoscopy under rEBUS and virtual bronchoscopic navigation guidance for small, peripheral pulmonary lesions. Furthermore, biopsy needles and cryoprobes have been miniaturized and adapted to the working channel of the new ultrathin bronchoscopes. Multi-modality and multi-instrumental ultrathin bronchoscopy using such new technologies has facilitated high diagnostic yields.

Guided Bronchoscopy for the Evaluation of Pulmonary Lesions: An Updated Meta-analysis

BACKGROUND

Guided bronchoscopy is increasingly used to diagnose peripheral pulmonary lesions (PPLs). A meta-analysis published in 2012 demonstrated a pooled diagnostic yield of 70%; however, recent publications have documented yields as low as 40% and as high as 90%.

RESEARCH QUESTION

Has the diagnostic yield of guided bronchoscopy in patients with PPLs improved over the past decade?

STUDY DESIGN AND METHODS

A comprehensive search was performed of studies evaluating the diagnostic yield of differing bronchoscopic technologies used to reach PPLs. Study quality was assessed using the Quality assessment of diagnostic accuracy of studies (QUADAS-2) assessment tool. Number of lesions, type of technology used, overall diagnostic yield, and yield by size were extracted. Adverse events were recorded. Meta-analytic techniques were used to summarize findings across all studies.

RESULTS

A total of 16,389 lesions from 126 studies were included. There was no significant difference in diagnostic yield prior to 2012 (39 studies; 3,052 lesions; yield 70.5%) vs after 2012 (87 studies; 13,535 lesions; yield 69.2%) (P > .05). Additionally, there was no significant difference in yield when comparing different technologies. Studies with low risk of overall bias had a lower diagnostic yield than those with high risk of bias (66% vs 71%, respectively; P = .018). Lesion size > 2 cm, presence of bronchus sign, and reports with a high prevalence of malignancy in the study population were associated with significantly higher diagnostic yield. Significant (P < .0001) between-study heterogeneity was also noted.

INTERPRETATION

Despite the reported advances in bronchoscopic technology to diagnose PPLs, the diagnostic yield of guided bronchoscopy has not improved.

Inheritance and innovation of the diagnosis of peripheral pulmonary lesions

As the leading cause of cancer-related deaths worldwide, early detection and diagnosis are crucial to reduce the mortality of lung cancer. To date, the diagnosis of the peripheral pulmonary lesions (PPLs) remains a major unmet clinical need. The urgency of diagnosing PPLs has driven a series of development of the advanced bronchoscopy-guided techniques in the past decades, such as radial probe-endobronchial ultrasonography (RP-EBUS), virtual bronchoscopy navigation (VBN), electromagnetic navigation bronchoscopy (ENB), bronchoscopic transparenchymal nodule access (BTPNA), and robotic-assisted bronchoscopy. However, these techniques also have their own limitations. In this review, we would like to introduce the development of diagnostic techniques for PPLs, with a special focus on biopsy approaches and advanced guided bronchoscopy techniques by discussing their advantages, limitations, and future prospects.

Diagnostic value of ultrathin bronchoscopy in peripheral pulmonary lesions: a narrative review

Flexible bronchoscopes are being continuously improved, and an ultrathin bronchoscope with a working channel that allows the use of a radial-type endobronchial ultrasound (EBUS) probe is now available. The ultrathin bronchoscope has good maneuverability for passing through the small bronchi and good accessibility to peripheral lung lesions. This utility is particularly enhanced when it is used with other imaging devices, such as EBUS and navigation devices. Multimodality bronchoscopy using an ultrathin bronchoscope leads to enhanced diagnostic yield.

An update on the role of bronchoscopy in the diagnosis of pulmonary disease

Bronchoscopy has evolved over the past few decades and has been used by respiratory physicians to diagnose various airway and lung diseases. With the popularization of medical check-ups and growing interest in health, early diagnosis of lung diseases is essential. With the development of endobronchial ultrasound, ultrathin bronchoscopy, and electromagnetic navigational bronchoscopy, bronchoscopy has been able to widen its scope in diagnosing pulmonary diseases. In this review, we have described the brief history, role, and complications of bronchoscopy used in diagnosing pulmonary lesions, from simple flexible bronchoscopy to bronchoscopy combined with several up-to-date technologies.

Bronchoscopic sampling techniques in the era of technological bronchoscopy

Flexible bronchoscopy is a key diagnostic and therapeutic tool. New endoscopes and technologically advanced navigational modalities have been recently introduced on the market and in clinical practice, mainly for the diagnosis of mediastinal lymph adenopathies and peripheral lung nodules. Bronchoscopic sampling tools have not changed significantly in the last three decades, with the sole exception of cryobiopsy. We carried out a non-systematic, narrative literature review aimed at summarizing the scientific evidence on the main indications/contraindications, diagnostic yield, and safety of the available bronchoscopic sampling techniques. Performance of bronchoalveolar lavage, bronchial washing, brushing, forceps biopsy, cryobiopsy and needle aspiration techniques are described, focusing on indications and diagnostic accuracy in the work-up of endobronchial lesions, peripheral pulmonary abnormalities, interstitial lung diseases, and/or hilar-mediastinal lymph adenopathies. Main factors affecting the diagnostic yield and the navigational methods are evaluated. Preliminary data on the utility of the newest sampling techniques (i.e., new needles, triple cytology needle brush, core biopsy system, and cautery-assisted transbronchial forceps biopsy) are shown. TAKE HOME MESSAGE: A deep knowledge of bronchoscopic sampling techniques is crucial in the era of technological bronchoscopy for an optimal management of respiratory diseases.

Technologies for targeting the peripheral pulmonary nodule including robotics

Bronchoscopic sampling of PPL was significantly advanced by the development of the endobronchial ultrasound guide sheath method in the 1990s. Since then, a range of technical and procedural techniques have further advanced diagnostic yields. These include the use of thinner bronchoscopes with better working channel diameters, understanding the importance of peripheral transbronchial needle aspiration, and virtual bronchoscopic assistance. These have enabled better sampling of smaller and more technically challenging lesions including ground-glass nodules. Most recently, robotic bronchoscopy has been developed which, among other refinements, allows fine control of visual bronchoscopic navigation by replacing movements directed by the hand with electronic consoles and trackballs, and innovatively integrate virtual with real bronchoscopic pathways. The requirement for PPL diagnosis and treatment is expected to increase with more chest CT performed as part of CT screening programmes.

Probe-based optical fiberscopy for the direct observation of peripheral pulmonary lesions

BACKGROUND

Peripheral pulmonary lesions are rarely observed directly before transbronchial biopsy. This study aimed to characterize the differences between malignant and benign peripheral pulmonary lesions according to the findings of direct observation using probe-based optical fiberscopy.

METHODS

Thirty patients who underwent probe-based optical fiberscopy in combination with bronchoscopy using endobronchial ultrasonography with a guide sheath for the evaluation of peripheral pulmonary lesions were prospectively included in this study. The patients were divided into the malignant and benign groups according to their final diagnosis. The findings of probe-based optical fiberscopy in the two groups were compared.

RESULTS

The numbers of patients who were diagnosed using histological or bacteriological analyses via bronchoscopic sampling in the malignant and benign groups were 20/23 (87.0%) and 2/7 (28.6%), respectively. On probe-based optical fiberscopy, angiogenesis and vascular engorgement were observed only in the malignant group. The disappearance of subepithelial microvessel transparency and presence of bronchiolar stenosis were observed more frequently in the malignant group (78.3% and 60.9%) than in the benign group (28.6% and 28.6%), whereas increased mucus secretion was observed more frequently in the benign group (71.4%) than in the malignant group (8.7%).

CONCLUSIONS

These results suggest that the findings of direct observation using probe-based optical fiberscopy are useful for differentiating malignant from benign peripheral pulmonary lesions.

TRIAL REGISTRY

UMIN-CTR; UMIN000018796; URL: https://www.umin.ac.jp/ctr/index.htm.

Advances in interventional diagnostic bronchoscopy for peripheral pulmonary lesions

Introduction: The incidence of peripheral pulmonary lesions (PPLs) is growing following the adoption of lung cancer screening by low-dose chest CT. Although CT-guided transthoracic needle aspiration has been the standard method to diagnose PPLs, the field of interventional bronchoscopy is rapidly advancing to overcome complications of the transthoracic approach yet maintain the yield. Areas covered: This article reviews the clinical evidence of recent emerging interventional bronchoscopic techniques for diagnosis of PPLs. Expert opinion: Recent advances in interventional bronchoscopy contribute to not only the safety of transbronchial approaches to PPLs but also the higher diagnostic yield. To perform accurate sampling of PPLs, bronchoscopists must select the correct airway, approach the target as close as possible, and confirm the location of the target before sampling. These key steps can be assisted by recently developed technologies. However, it is important for bronchoscopists to understand the strengths and limitations of these emerging technologies.

Diagnostic Yield of the Virtual Bronchoscopic Navigation System Guided Sampling of Peripheral Lung Lesions using Ultrathin Bronchoscope and Protected Bronchial Brush

OBJECTIVES

The use of an ultrathin bronchoscope (UB) to diagnose peripheral pulmonary lesions is described. A virtual bronchoscopic navigation system was used to direct the ultrathin scope to the nodule. One of the constraints of this technique was the inability to confirm the target lesion position during biopsy by using a conventional linear endobronchial ultrasound probe, since the probe does not fit into a 1.2 mm working channel of this bronchoscope. The aim of the study was to review our institutional experience with the use of a UB for sampling peripheral pulmonary lesions using the transbronchial brush guided by virtual bronchoscopy. We describe a technique wherein we attempt to brush all the visible bronchial sub-segments once the bronchoscope has reached close to the nodule.

MATERIALS AND METHODS

In total, 52 patients underwent the procedure between 2010 and 2017. A multiplanar computed tomography (CT) scan of the chest was obtained and subsequently uploaded to the Lung Point Virtual bronchoscopy navigation software. The UB was parked close to the lesion. All visible airway branches were then brushed using a protected bronchial brush. The data were retrospectively abstracted from the electronic medical records using standardized forms.

RESULTS

A total of 52 lesions (40 solid, 8 part-solid, 3 cavitary, and 1 ground-glass) were sampled using a transbronchial brush (median, 2; range, 1-8). Twenty-four lesions were under 2 cm in size. The overall success rates were 67.3%. The average diameter of nodules was 2.7±1.01 cm; 65% lesions were in the outer-third of the lungs. The cancer-specific sensitivity was 72.5%. The presence of bronchus sign; location of the lesion; and the characteristics, size, and stage of cancer did not have any impact on the diagnostic yield.

CONCLUSION

Virtual bronchoscopy-guided ultrathin bronchoscopy with bronchial brushing is safe and has a diagnostic yield comparable to other described techniques for evaluating peripheral pulmonary nodules.

Combined virtual-assisted lung mapping (VAL-MAP) with CT-guided localization in thoracoscopic pulmonary segmentectomy

BACKGROUND/OBJECTIVE

Virtual assisted lung mapping (VAL-MAP) is a bronchoscopic lung marking technique developed to assist in navigational lung resection. It can be used for nodule localization and segmental identification. This article presents our initial experience of thoracoscopic pulmonary segmentectomy using combined VAL-MAP and computed tomography (CT)-guided localization.

MATERIAL AND METHODS

Markings with India Ink were made bronchoscopically, before surgery, using a virtual bronchoscopy system (LungPoint® Planner) without fluoroscopy guidance. Post VAL-MAP CT scans localized the actual markings. All data on patients, markings, and outcomes were retrospectively collected, and the contribution of VAL-MAP to the operation was graded by the surgeon.

RESULTS

From March 2017 to September 2017, 24 consecutive patients received the VAL-MAP marking procedure before thoracoscopic segmentectomy. Nineteen patients also received pre-operative CT-guided percutaneous localization after VAL-MAP; fifteen patients received CT-guided localization with dye (patent blue V) and microcoil, and four patients received with dye only. Of the 101 marking attempts made in all the patients, 71 (70.3%) were identified as contributing to the surgery. No clinically evident complications were associated with the procedure. A total of 24 segmentectomies were thoracoscopically conducted for 18 cases of lung cancer and six cases of benign diseases.

CONCLUSION

The combination of VAL-MAP and CT-guided percutaneous localization contribute to precise thoracoscopic pulmonary segmentectomy.

Bronchoscopy for the diagnosis of peripheral lung lesions

Peripheral pulmonary lesions (PPLs) are generally considered as lesions in the peripheral one-third of the lung although a precise definition and radiographic anatomical landmarks separating central and peripheral lesion does not yet exist. The radiographic detection of such lesions has increased significantly with the adoption of lung cancer screening programs. These lesions are not directly visible by regular flexible bronchoscopes as they are usually distal to the lobar and segmental bronchi. Traditionally, depending on location and clinical stage at presentation, these lesions were typically sampled by computerized tomography (CT) guided needle or surgical biopsy although some centers also used ultrasound and fluoroscopy guided percutaneous needle biopsy. Due to lack of direct visualization, the yield for bronchoscopic guided sampling especially of the small <2 cm pulmonary nodules was very low. Therefore, sampling has been preferentially performed by percutaneous CT guidance, which had high yield of above 90% but it comes at the cost of higher risk complications like pneumothorax with reported rate of 15% to 28%. Directly proceeding to surgical resection is also considered in appropriate candidates with high suspicion of malignancy without any evidence of distant metastasis but the proportion of such cases of lung cancer is low. The manuscript discussed the various bronchoscopic diagnostic modalities for peripheral pulmonary lesions. It is important to note that most of the studies in this field are relatively small, not randomized, suffer from selection bias, have considerable heterogeneity in sampling methodology/instruments and usually have been performed in high volume institutions by dedicated highly experienced proceduralists. The prevalence of malignancy in most of the reported cohorts has also been high which may result in higher diagnostic yields. All these factors need to be kept in mind before generalizing the results to individual centers and practices.

[Application of Interventional Bronchoscopy in Pulmonary Peripheral Lesions]

肺癌是全球癌症相关死亡的主要原因, 肺癌的治愈率很低, 不仅因其自身攻击性, 还因对肺癌筛查的忽视。随着肺部筛查手段的不断进展, 肺外周病变的检出率逐渐提高, 当前对外周肺病变进行诊断的最常用方法是经支气管行支气管镜检查或计算机断层扫描(computed tomography, CT)引导下经皮穿刺针吸/活检, 然而对于外周肺病灶, 支气管镜检查有较低的诊断率, 经皮穿刺检查有较高的气胸发生率, 因此, 使用安全、微创的方法对外周肺病变进行组织确诊是临床工作者将面临的挑战。新型支气管镜介入诊断技术已逐渐用于临床, 这些技术可有效提高外周肺病变的诊断率, 缩短诊断时间, 使患者获得及时有效的治疗。本文将现有的技术进行简要综述以帮助临床医生尝试应用这些微创技术。

Recent advances in diagnostic bronchoscopy

The field of diagnostic bronchoscopy has been revolutionized in the last decade primarily with the advent of endobronchial ultrasound (EBUS) but also with the addition of multiple different techniques for "guided-bronchoscopy". These advances have had a substantial impact in the management of lung cancer with bronchoscopy now providing both diagnosis and mediastinal staging in a single procedure. EBUS has, in fact, become the first choice for staging of the mediastinum over cervical mediastinoscopy (CM). Although EBUS is now a well-established technique, there are continuous efforts from the scientific community to improve its diagnostic performance, and these will be reviewed in this manuscript. The term "guided-bronchoscopy" was recently coined to describe a myriad of techniques that guide our bronchoscopes or bronchoscopic tools into the periphery of the lungs in addition to our conventional fluoroscopy. Electromagnetic and non-electromagnetic navigation, thin and ultrathin scopes, as well as radial-probe EBUS have collectively increased our yield for smaller peripheral lung lesions and continue to evolve. Despite this improved diagnostic yield, there is still ample room for improvement and newer techniques are under way. With new therapies available for patients with interstitial lung disease, achieving a specific histologic diagnosis is now of paramount importance. Given the high morbidity and mortality of surgical biopsies, bronchoscopic cryobiopsy is being rapidly adopted as a safer and effective alternative, and it is likely going to play a major role in the management of these diseases in the near future. This manuscript we will focus on recent advances in EBUS, guided-bronchoscopy, and the use of cryobiopsy.

Ultrathin bronchoscopy for solitary pulmonary lesions in a region endemic for tuberculosis: a randomised pilot trial

Background

The evaluation of solitary pulmonary lesions (SPL) requires a balance between procedure-related morbidity and diagnostic yield, particularly in areas where tuberculosis (TB) is endemic. Data on ultrathin bronchoscopy (UB) for this purpose is limited. To evaluate feasibility and safety of UB compared to SB for diagnosis of SPL in a TB endemic region.

Methods

In this prospective randomised trial we compared diagnostic yield and adverse events of UB with standard-size bronchoscopy (SB), both combined with fluoroscopy, in a cohort of patients with SPL located beyond the visible range of SB.

Results

We included 40 patients (mean age 55.2 years, 45 % male) with malignant SPL (n = 16; 40 %), tuberculous SPL (n = 11; 27.5 %) and other benign SPL (n = 13; 32.5 %). Mean procedure time in UB and SB was 30.6 and 26.0 min, respectively (p = 0.15). By trend, adverse events were recorded more often with UB than with SB (30.0 vs. 5.0 %, p = 0.091), including extensive coughing (n = 2), blocked working channel (n = 2), and arterial hypertension requiring therapeutic intervention (n = 1), all with UB. The overall diagnostic yield of UB compared to SB was 55.0 % vs. 80.0 %, respectively (p = 0.18). Sensitivity for the diagnosis of malignancy of UB and SB was 50.0 % and 62.5 %, respectively (p = 0.95).

Conclusion

UB is not superior to SB for the evaluation of SPL in a region endemic with tuberculosis, when combined with fluoroscopic guidance only.

Trial registration

ClinicalTrials.gov (Identifier: NCT02490059).

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0225-1) contains supplementary material, which is available to authorized users.

Early diagnosis of solitary pulmonary nodules

Early detection of solitary pulmonary nodules (SPNs) and early treatment are of great importance. However, patients with early SPNs always do not present with any symptoms or signs, only to demonstrate SPNs in radiology findings. So it is very critical to improve the ability to identify the SPNs, and with the development of sorts of diagnostic modalities, the accuracy in the evaluation of the SPNs has improved greatly. In this paper, the diagnostic methods and techniques of SPNs are reviewed.

Diagnostic bronchoscopy--current and future perspectives

Lung cancer is the leading cause of cancer-related mortality worldwide. Standard bronchoscopy has limited ability to accurately localise and biopsy pulmonary lesions that cannot be directly visualised. The field of advanced diagnostic bronchoscopy is rapidly evolving due to advances in electronics and miniaturisation. Bronchoscopes with smaller outer working diameters, coupled with miniature radial and convex ultrasound probes, allow accurate central and peripheral pulmonary lesion localisation and biopsy while at the same time avoiding vascular structures. Increases in computational processing power allow three-dimensional reconstruction of computed tomographic raw data to enable virtual bronchoscopy (VB), providing the bronchoscopist with a preview of the bronchoscopy prior to the procedure. Navigational bronchoscopy enables targeting of peripheral pulmonary lesions (PPLs) via a "roadmap", similar to in-car global positioning systems. Analysis of lesions on a cellular level is now possible with techniques such as optical coherence tomography (OCT) and confocal microscopy (CM). All these tools will hopefully allow earlier and safer lung cancer diagnosis and in turn better patient outcomes. This article describes these new bronchoscopic techniques and reviews the relevant literature.

Ultrathin bronchoscopy in the diagnosis of peripheral cavitary lung lesions

Ultrathin (UT) bronchoscopy has emerged as a useful tool to diagnose peripheral solid lung lesions of a malignant nature. This technology is superior to standard bronchoscopic techniques, which have low yield in identifying small lesions, especially as they extend further out along the bronchial tree. UT bronchoscopy can prevent the need to pursue more invasive open lung strategies to diagnose suspicious lesions. In this report, we present 3 distinct clinical scenarios where UT bronchoscopy was successful in diagnosing benign peripheral cavitary lesions after standard techniques failed. The use of UT bronchoscopy in each case was instrumental in allowing rapid initiation of appropriate therapy without need for more invasive surgical biopsies in the setting of a benign condition.

Newer modalities in the work-up of peripheral pulmonary nodules

Technological advances in recent years have translated into the availability of newer modalities to establish the cause of peripheral pulmonary nodules (PPN). Even though the verdict is still out on the ideal diagnostic modality, there is no doubt that the bronchoscope is becoming a popular tool in the armamentarium of physicians who deal with PPN. This article focuses on newer bronchoscopic modalities being studied for the work-up of PPN. The authors also summarize the value of established diagnostic modalities to provide a balanced perspective.

Advances and future directions in interventional pulmonology

The term "interventional pulmonology" (IP) supersedes the previously used term "thoracic endoscopy," a change that reflects the evolution of a specialty devoted to performing highly sophisticated and technologically advanced procedures in the lungs and chest. Continuing advances in technology promise to further expand IP's diagnostic and therapeutic frontiers. However, standardized educational programs to train and test IP physicians will be essential to maintain a high standard of practice in the field.

Hybrid electromagnetic and image-based tracking of endoscopes with guaranteed smooth output

PURPOSE

Flexible fiber-optic bronchoscopy is a widespread medical procedure for the diagnosis and treatment of lung diseases. Navigation systems are needed to track the flexible endoscope within the bronchial tree. Electromagnetic (EM) tracking is currently the only technology used clinically for this purpose. The registration between EM tracking and patient anatomy may become inaccurate due to breathing motion, so the addition of image-based tracking has been proposed as a hybrid EM-image-based system.

METHODS

When EM tracking is used as an initialization for image registration, small changes in the initialization may lead to different local minima and noise is amplified by hybrid tracking. The tracking output is modeled as continuous and uses splines for interpolation, thus smoothness is greatly improved. The bronchoscope pose relative to computed tomography data is interpolated using Catmull-Rom splines for position and spherical linear interpolation (SLERP) for orientation.

RESULTS

The hybrid method was evaluated using ground truth poses manually selected by experts, where mean inter-expert agreement was determined as 1.26 mm. Using four dynamic phantom data sets, the accuracy was 4.91 mm, which is equivalent to previous methods. Compared to state-of-art methods, inter-frame smoothness was improved from 2.77-3.72 to 1.24 mm.

CONCLUSIONS

Hybrid image and electromagnetic endoscope guidance provides a more realistic and physically plausible solution with significantly less jitter. This quantitative result is confirmed by visual comparison of real and virtual video, where the virtual video output is much more consistent and robust, with fewer occasions of tracking loss or unexpected movement compared with previous methods.

Meta-analysis of guided bronchoscopy for the evaluation of the pulmonary nodule

BACKGROUND

The detection of pulmonary nodules (PNs) is likely to increase, especially with the release of the National Lung Screen Trials. When tissue diagnosis is desired, transthoracic needle aspiration (TTNA) is recommended. Several guided-bronchoscopy technologies have been developed to improve the yield of transbronchial biopsy for PN diagnosis: electromagnetic navigation bronchoscopy (ENB), virtual bronchoscopy (VB), radial endobronchial ultrasound (R-EBUS), ultrathin bronchoscope, and guide sheath. We undertook this meta-analysis to determine the overall diagnostic yield of guided bronchoscopy using one or a combination of the modalities described here.

METHODS

We performed a MEDLINE search using “bronchoscopy” and “solitary pulmonary nodule.” Studies evaluating the diagnostic yield of ENB, VB, R-EBUS, ultrathin bronchoscope, and/or guide sheath for peripheral nodules were included. The overall diagnostic yield and yield based on size were extracted. Adverse events, if reported, were recorded. Meta-analysis techniques incorporating inverse variance weighting and a random-effects meta-analysis approach were used.

RESULTS

A total of 3,052 lesions from 39 studies were included. The pooled diagnostic yield was 70%, which is higher than the yield for traditional transbronchial biopsy. The yield increased as the lesion size increased. The pneumothorax rate was 1.5%, which is significantly smaller than that reported for TTNA.

CONCLUSION

This meta-analysis shows that the diagnostic yield of guided bronchoscopic techniques is better than that of traditional transbronchial biopsy. Although the yield remains lower than that of TTNA, the procedural risk is lower. Guided bronchoscopy may be an alternative or be complementary to TTNA for tissue sampling of PN, but further study is needed to determine its role in the evaluation of peripheral pulmonary lesions.

Deformable registration of bronchoscopic video sequences to CT volumes with guaranteed smooth output

We present a novel approach to tracking of flexible bronchoscopes by modeling the output as spatially continuous over time. Bronchoscopy is a widespread clinical procedure for diagnosis and treatment of lung diseases and navigation systems are highly needed. Tracking of the bronchoscope can be regarded as a deformable registration problem. In our approach we use hybrid image-based and electromagnetic tracking, and the bronchoscope pose relative to CT data is interpolated using Catmull-Rom splines for position and SLERP for orientation. We evaluate the method using ground truth poses manually selected by experts, where mean inter-expert agreement was determined as 1.26 mm. For four dynamic phantom data sets, the accuracy of our method is between 4.13 and 5.93 mm and shown to be equivalent to previous methods. We significantly improve inter-frame smoothness from 2.35-3.08 mm to 1.08-1.51 mm. Our method provides a more realistic and physically plausible solution with significantly less jitter. This quantitative result is confirmed by video output, which is much more consistent and robust, with fewer occasions of tracking loss or unexpected movement.

CT-guided ultrathin bronchoscopy: bioptic approach and factors in predicting diagnosis

BACKGROUND

The diagnostic sensitivity of current bronchoscopy for peripheral lung cancer is inadequate because the bronchoscope insertion range is limited and confirmation of the position of the biopsy apparatus at the lesion under X-ray fluoroscopy is inaccurate. The combination of ultrathin bronchoscopy and computed tomography (CT) is effective for solving these problems.

OBJECTIVE

This study was a retrospective study analyzing prospectively collected data to identify factors contributing to the diagnosis and the appropriate biopsy method in CT-guided ultrathin bronchoscopy for peripheral lung cancer.

METHODS

The subjects comprised 86 patients (88 lesions) who underwent CT-guided ultrathin bronchoscopy and were finally diagnosed with peripheral lung cancer. We evaluated the diagnostic yield according to specific factors and also according to the sample collection method.

RESULTS

Sixty-nine lesions were diagnosed as lung cancer, and the diagnostic yield was 78.4% (80.3% in lesions ≤2 cm in diameter). Multivariate analysis showed that the factors contributing to the diagnosis were the observation range by ultrathin bronchoscopy and the presence/absence of the involved bronchus or pulmonary artery. Pathological evaluation facilitated histological diagnoses in 53 (65.4%) of 81 lesions. In 16 lesions, only the cytological diagnosis was positive.

CONCLUSION

CT-guided ultrathin bronchoscopy may be particularly useful for lesions for which the involved bronchus or pulmonary artery can be confirmed, and observation of bronchi of the 6th generation or more is possible. Since the specimen preparation rate is low, the combination of histopathological diagnosis with cytological diagnosis particularly that of the discharge attached to the forceps, is optimal.

Endobronchial ultrasound-guided transbronchial biopsy using novel thin bronchoscope for diagnosis of peripheral pulmonary lesions

BACKGROUND

The aim of this study was to evaluate the diagnostic utility of endobronchial ultrasound (EBUS)-guided transbronchial biopsy (TBB) using a novel 3.4-mm thin bronchoscope and a 1.4-mm ultrasonic probe for peripheral pulmonary lesions.

METHODS

A total of 86 patients with suspected peripheral lesions were included in this prospective study. EBUS-TBBs were performed using a prototype 3.4-mm thin bronchoscope and a 1.4-mm radial ultrasonic probe under fluoroscopic guidance.

RESULTS

Twelve patients with endobronchial lesions within the segmental bronchi and three patients who did not return to follow-up were excluded from this analysis. Thus, a total of 71 patients with peripheral pulmonary lesions (mean size, 31.2 +/- 12.7 mm) were included in the final analysis. The mean bronchus level reached with the thin bronchoscope was 4.6 generations. Diagnostic histologic specimens were obtained in 49 of 71 patients (69%:80% for malignant lesions and 52% for benign lesions). A definitive diagnosis of malignancy for lesions > or =20 mm and lesions < 20 mm was made in 82% (31 of 38) and 67% (four of six), respectively. There were no significant complications.

CONCLUSION

The EBUS-TBB using a 3.4-mm thin bronchoscope and a 1.4-mm radial probe is feasible, accurate, and safe for the diagnosis of peripheral pulmonary lesions.

A novel needle-type sampling device for flexible ultrathin bronchoscopy

Diagnosis of suspected cancer in the periphery of the lung is difficult. A flexible ultrathin bronchoscope has been developed for the diagnosis of peripherally located pulmonary lesions that cannot be reached with the sampling devices for standard flexible bronchoscopes. The diagnostic yield with forceps and a brush for ultrathin bronchoscopes, however, is not adequate, especially when a lesion is not exposed to the bronchial lumen. We have thus developed a novel needle-type sampling device and tested its yield in transbronchial cytology. The device consists of an elongated dental H-file (0.4 mm in diameter and 110 cm in length), a housing sheath (1.0 mm in outer diameter), and a novel handle, which enables rapid out-and-in motion of the needle. Ten consecutive patients with a peripheral pulmonary lesion who had an indication for diagnostic procedure with a flexible ultrathin bronchoscope were enrolled. The optimal bronchial route to the lesion was analyzed with virtual bronchoscopy in a data set obtained with high-resolution computed tomography, and a novel bronchial route labeling system (prior-ridge-based relative orientation nomenclature) was employed to guide insertion of the bronchoscope. Sampling with the novel needle was performed prior to use of the forceps and brush under conventional fluoroscopy. In all the cases, sampling with the needle was successful and the amount of the specimen was sufficient for cytology. Our novel sampling system with flexible ultrathin bronchoscopes may contribute to accurate and minimally invasive diagnosis of peripheral pulmonary lesions.

Virtual bronchoscopic navigation system shortens the examination time—Feasibility study of virtual bronchoscopic navigation system

Computed tomography (CT)-guided transbronchial biopsy (TBB) using an ultrathin bronchoscope with simulation by virtual bronchoscopy (VB) is effective for diagnosing small peripheral pulmonary lesions. However, we occasionally lose the proper bronchi to the lesion when a bronchoscope is inserted into peripheral bronchi with severe rotation. To overcome this problem, the virtual bronchoscopic navigation system that can display real-time VB images during TBB procedures in comparison with actual bronchi has been developed. We evaluated the usefulness of the virtual bronchoscopic navigation system for CT-guided TBB using an ultrathin bronchoscope (navigation method) to diagnose small peripheral pulmonary lesions, and compared the results to those with previous method that uses VB images in a simulation (simulation method). We performed CT-guided TBB using an ultrathin bronchoscope for 69 patients with 71 small peripheral pulmonary lesions (mean diameter, 13.7 mm) between November 2002 and November 2005 with the navigation method. CT-guided TBB with the navigation method was performed safely without any serious complications for all patients. Mean time to the initial scan, time to the first biopsy and total examination time were 5.3, 8.5 and 24.5 min, respectively. Fifty lesions (70%) were diagnosed by this procedure. Compared to simulation method, diagnostic sensitivity was higher in the navigation method, but the difference was not significant. However, the time to the first biopsy and total examination time were significantly shorter in the navigation method than in the simulation method (p<0.05). In summary, the virtual bronchoscopic navigation system was safely used, effective for diagnosing small peripheral pulmonary lesions, and useful for shortening the examination time of CT-guided TBB using an ultrathin bronchoscope.

Factors Related to Diagnostic Sensitivity Using an Ultrathin Bronchoscope Under CT Guidance

BACKGROUND

We investigated factors related to the diagnostic sensitivity of CT-guided transbronchial biopsy (TBB) using an ultrathin bronchoscope and virtual bronchoscopy (VB) navigation for small peripheral pulmonary lesions.

METHOD

We have performed this procedure on 83 patients with 85 small peripheral pulmonary lesions (< 20 mm in diameter). We analyzed the relationship between the diagnostic sensitivity and the location of the lesions, the bronchial generation to which an ultrathin bronchoscope was inserted, and the lesion-bronchial and lesion-pulmonary arterial relationships on high-resolution CT.

RESULTS

Fifty-six of the 85 lesions (66%) were diagnosed following CT-guided TBB using an ultrathin bronchoscope with VB navigation. The lesions located in the left superior segment of the lower lobe (S6) had a significantly low diagnostic sensitivity compared to other locations (p < 0.01). When an ultrathin bronchoscope could be inserted to the fifth or greater bronchial generation, the yield was above the average diagnostic sensitivity of 66%. Moreover, not only the patients with the presence of a bronchus leading directly to a lesion (CT-bronchus sign), but also the patients with the presence of a pulmonary artery leading to a lesion (CT-artery sign), had high diagnostic sensitivity (p < 0.01). Multivariate analysis revealed that the location of lesion was an independent predictor of diagnostic sensitivity (p < 0.05).

CONCLUSIONS

The location of the lesion, the bronchial generation to which an ultrathin bronchoscope was inserted, and the presence of a bronchus as well as a pulmonary artery leading to the lesion were valuable for predicting successful CT-guided TBB using an ultrathin bronchoscope with VB navigation.

Cavitating Invasive Pulmonary Aspergillosis Visualized and Diagnosed by Ultrathin Bronchoscopy

A definitive diagnosis of invasive pulmonary aspergillosis (IPA), which usually occurs in immunocompromised patients, is often difficult. We report two cases of cavitating IPA in a peripheral pulmonary region in patients who were receiving corticosteroids, in whom the cavity was successfully visualized and sampled during ultrathin bronchoscopy. Ultrathin bronchoscopy provides a new option for definitive diagnosis of cavitating IPA.