Real-time electromagnetic navigation bronchoscopy to peripheral lung lesions using overlaid CT images: the first human study

Augmented reality guided versus computed tomography guided percutaneous lung nodule localization: a noninferiority randomized clinical trial

HYPOTHESIS

This study hypothesized that augmented reality (AR) technology has comparable accuracy and safety to conventional CT localization in guiding percutaneous transthoracic lung puncture (PTLP) to localize small pulmonary nodules.

METHODS

This study was a prospective, non-inferiority randomized clinical trial. Patients were randomly assigned between 23 May 2023, and 26 September 2023. Patients with small peripheral lung nodules (≤2 cm) were recruited. Patients were randomly assigned to either the CT-guided PTLP group or the AR-guided PTLP group, with a 1:1 allocation ratio. The primary outcome was the accuracy of lung nodule localization measured by localization error. The secondary outcomes included procedure duration, radiation exposure dosage and complications.

RESULTS

A total of 70 patients underwent either CT- or AR-guided lung nodule localization and subsequent surgeries. Localization error was smaller in the AR-guided group than in the CT-guided group (mean ± SD, 3.1 ± 4.0 mm vs. 5.4 ± 4.2 mm, P = 0.026). The mean difference of localization errors was -2.3 mm (95% CI: - 4.2 to -0.3 mm, P < 0.001 for non-inferiority). Compared to the CT-guided group, the AR-guided group demonstrated significantly lower radiation exposure (mean ± SD, 421 ± 168 vs. 694 ± 229 mGy × cm, P < 0.001) and shorter localization procedure duration (mean ± SD, 8.8 ± 2.3 vs. 14.1 ± 1.8 minutes, P < 0.001), with no statistical difference in complications.

CONCLUSIONS

The accuracy of the AR-guided approach is comparable to that of the CT-guided approach in localizing small lung nodules. Furthermore, the utilization of AR technology has been demonstrated to reduce procedural time and minimize radiation exposure for patients.

A bronchoscopic navigation method based on neural radiation fields

PURPOSE

We introduce a novel approach for bronchoscopic navigation that leverages neural radiance fields (NeRF) to passively locate the endoscope solely from bronchoscopic images. This approach aims to overcome the limitations and challenges of current bronchoscopic navigation tools that rely on external infrastructures or require active adjustment of the bronchoscope.

METHODS

To address the challenges, we leverage NeRF for bronchoscopic navigation, enabling passive endoscope localization from bronchoscopic images. We develop a two-stage pipeline: offline training using preoperative data and online passive pose estimation during surgery. To enhance performance, we employ Anderson acceleration and incorporate semantic appearance transfer to deal with the sim-to-real gap between training and inference stages.

RESULTS

We assessed the viability of our approach by conducting tests on virtual bronchscopic images and a physical phantom against the SLAM-based methods. The average rotation error in our virtual dataset is about 3.18∘ and the translation error is around 4.95 mm. On the physical phantom test, the average rotation and translation error are approximately 5.14∘ and 13.12 mm.

CONCLUSION

Our NeRF-based bronchoscopic navigation method eliminates reliance on external infrastructures and active adjustments, offering promising advancements in bronchoscopic navigation. Experimental validation on simulation and real-world phantom models demonstrates its efficacy in addressing challenges like low texture and challenging lighting conditions.

Comparison of electromagnetic navigation bronchoscopy localization and CT-guided percutaneous localization in resection of lung nodules: A protocol for systematic review and meta-analysis

BACKGROUND

This study aimed to evaluate the efficacy and safety between electromagnetic navigational bronchoscopy (ENB) and computed tomography (CT)-guided percutaneous localization before resection of pulmonary nodules.

METHODS

Pubmed, Embase, Web of Science, and the Cochrane Library databases were searched from January 1, 2000 to April 30, 2022, for relevant studies. Two reviewers conducted the search, selection, and extraction of data from eligible studies. The risk of bias was assessed using the Newcastle-Ottawa Scale. The primary outcome was the localization success rate, and the secondary outcomes were the pneumothorax incidence and localization time. The meta-analysis was performed by Review Manager 5.4. The protocol for the meta-analysis was registered on PROSPERO (Registration number: CRD42022345972).

RESULTS

Five cohort studies comprising 441 patients (ENB group: 185, CT group: 256) were analyzed. Compared with the CT-guided group, the ENB-guided group was associated with lower pneumothorax incidence (relative ratio = 0.16, 95% confidence interval [CI]: 0.04-0.65, P = .01). No significant differences were found in location success rates (relative ratio = 1.01, 95% CI: 0.98-1.05, P = .38) and localization time (mean difference = 0.99, 95% CI: -5.73 to 7.71, P = .77) between the ENB group and CT group.

CONCLUSION

Both ENB and CT-guided are valuable technologies in localizing lung nodules before video-assisted thoracoscopic surgery based on current investigations. ENB achieved a lower pneumothorax rate than the CT-guided group. In our opinion, there is no perfect method, and decision-making should be given the actual circumstances of each institute. Future prospective studies in the form of a randomized trial are needed to confirm their clinical value.

Navigated ultrasound bronchoscopy with integrated positron emission tomography-A human feasibility study

BACKGROUND AND OBJECTIVE

Patients suspected to have lung cancer, undergo endobronchial ultrasound bronchoscopy (EBUS) for the purpose of diagnosis and staging. For presumptive curable patients, the EBUS bronchoscopy is planned based on images and data from computed tomography (CT) images and positron emission tomography (PET). Our study aimed to evaluate the feasibility of a multimodal electromagnetic navigation platform for EBUS bronchoscopy, integrating ultrasound and segmented CT, and PET scan imaging data.

METHODS

The proof-of-concept study included patients with suspected lung cancer and pathological mediastinal/hilar lymph nodes identified on both CT and PET scans. Images obtained from these two modalities were segmented to delineate target lymph nodes and then incorporated into the CustusX navigation platform. The EBUS bronchoscope was equipped with a sensor, calibrated, and affixed to a 3D printed click-on device positioned at the bronchoscope's tip. Navigation accuracy was measured postoperatively using ultrasound recordings.

RESULTS

The study enrolled three patients, all presenting with suspected mediastinal lymph node metastasis (N1-3). All PET-positive lymph nodes were displayed in the navigation platform during the EBUS procedures. In total, five distinct lymph nodes were sampled, yielding malignant cells from three nodes and lymphocytes from the remaining two. The median accuracy of the navigation system was 7.7 mm.

CONCLUSION

Our study introduces a feasible multimodal electromagnetic navigation platform that combines intraoperative ultrasound with preoperative segmented CT and PET imaging data for EBUS lymph node staging examinations. This innovative approach holds promise for enhancing the accuracy and effectiveness of EBUS procedures.

Distortion-Free Magnetic Tracking of Metal Instruments in Image-Guided Interventions

Electromagnetic tracking (EMT) can benefit image-guided interventions in cases where line of sight is unavailable. However, EMT can suffer from electromagnetic distortion in the presence of metal instruments. Metal instruments are widely used in laparoscopic surgery, ENT surgery, arthroscopy and many other clinical applications. In this work, we investigate the feasibility of tracking such metal instruments by placing the inductive sensor within the instrument shaft. We propose a magnetostatic model of the field within the instrument, and verify the results experimentally for frequencies from 6 kHz to 60 kHz. The impact of the instrument's dimensions, conductivity and transmitting field frequency is quantified for ranges representative of typical metal instruments used in image-guided interventions. We then performed tracking using the open-source Anser EMT system and quantify the error caused by the presence of the rod as a function of the frequency of the eight emitting coils for the system. The work clearly demonstrates why smaller tool diameters (less than 8 mm) are less susceptible to distortion, as well as identifying optimal frequencies (1 kHz to 2 kHz) for transmitter design to minimise for distortion in larger instruments.

Improving diagnostic strategies in bronchoscopy for peripheral pulmonary lesions

INTRODUCTION

In the past two decades, bronchoscopy of peripheral pulmonary lesions (PPLs) has improved its diagnostic yield due to the combination of various instruments and devices. Meanwhile, the application is complex and intertwined.

AREAS COVERED

This review article outlines strategies in diagnostic bronchoscopy for PPLs. We summarize the utility and evidence of key instruments and devices based on the results of clinical trials. Future perspectives of bronchoscopy for PPLs are also discussed.

EXPERT OPINION

The accuracy of reaching PPLs by bronchoscopy has improved significantly with the introduction of combined instruments such as navigation, radial endobronchial ultrasound, digital tomosynthesis, and cone-beam computed tomography. It has been accelerated with the advent of approach tools such as newer ultrathin bronchoscopes and robotic-assisted bronchoscopy. In addition, needle aspiration and cryobiopsy provide further diagnostic opportunities beyond forceps biopsy. Rapid on-site evaluation may also play an important role in decision making during the procedures. As a result, the diagnostic yield of bronchoscopy for PPLs has improved to a level comparable to that of transthoracic needle biopsy. The techniques and technologies developed in the diagnosis will be carried over to the next step in the transbronchial treatment of PPLs in the future.

Evaluation of the diagnostic role of radial probe endobronchial ultrasound for peripheral pulmonary lesions

OBJECTIVE

To evaluate the predictive value of echo features of radial probe endobronchial ultrasound (RP-EBUS) in the differential diagnosis of malignant and benign 1esions.

METHODS

The clinical data of 336 patients with peripheral pulmonary lesions (PPLs) undergoing RP-EBUS were analyzed in order to evaluate the predictive value of the three EBUS echo features including continuous margin, absence of a linear-discrete air bronchogram, and heterogeneous in pulmonary lesions. The sensitivity and specificity for each echoic feature or in combination in diagnosing malignancy or benignity were determined.

RESULTS

336 cases of PPLs including 216 cases of malignant lesions and 120 cases of benign lesions. The sensitivity and specificity of the continuous margin to the diagnosis of malignant lesions were 86.11% and 17.50%. The sensitivity and specificity of the absence of a linear-discrete air bronchogram to the diagnosis of malignant lesions were 66.67% and 57.50%, and the positive predictive value was 73.85%. The sensitivity and specificity of heterogeneity to the diagnosis of malignant lesions were 65.28% and 72.50%, and the positive predictive value was 81.03%. The combination of heterogeneous and absence of a linear-discrete air bronchogram could improve the diagnostic specificity to 87.50%, and the positive predictive value to 80.77%.

CONCLUSION

The two EBUS echo features of heterogeneous and absence of a linear-discrete air bronchogram have predictive value for PPLs, especially in the presence of two features the pulmonary lesions should be highly suspected malignant tumors.

Electromagnetic Navigational Bronchoscopy Learning Curve Regarding Pneumothorax Rate and Diagnostic Yield

Electromagnetic navigational bronchoscopy (ENB) has emerged as an innovative technique for diagnosing peripheral and central nodules, offering an improved diagnostic yield compared to conventional bronchoscopy with fewer complications. That being said, pneumothorax remains a frequent complication. This retrospective study conducted at Castle Hill Hospital, UK, analysed ENB procedures over four years to assess the diagnostic yield and pneumothorax rates, exploring learning curves and procedural improvements specifically focusing on the diagnostic yield and pneumothorax rate as markers of change. A total of 246 patients underwent 358 peripheral lung biopsies, revealing an overall diagnostic yield of 61.3%. The diagnostic yield increased from 58.2% in 2020-2021 to 66.0% in 2022-2023 while the pneumothorax rate decreased significantly from 9.8% to 3.4% (p = 0.021*). The majority of pneumothorax cases occurred following upper lobe procedures. The study depicts the importance of procedural experience in improving outcomes, suggesting a learning curve effect. Additionally, it emphasizes the potential for technological advancements, such as robotic assistance, to mitigate operator-dependent variability and improve reproducibility in ENB procedures. These findings contribute to optimizing diagnostic pathways for lung lesions and improving patient safety in ENB interventions.

Augmented Reality Navigation System for Biliary Interventional Procedures With Dynamic Respiratory Motion Correction

OBJECTIVE

Biliary interventional procedures require physicians to track the interventional instrument tip (Tip) precisely with X-ray image. However, Tip positioning relies heavily on the physicians' experience due to the limitations of X-ray imaging and the respiratory interference, which leads to biliary damage, prolonged operation time, and increased X-ray radiation.

METHODS

We construct an augmented reality (AR) navigation system for biliary interventional procedures. It includes system calibration, respiratory motion correction and fusion navigation. Firstly, the magnetic and 3D computed tomography (CT) coordinates are aligned through system calibration. Secondly, a respiratory motion correction method based on manifold regularization is proposed to correct the misalignment of the two coordinates caused by respiratory motion. Thirdly, the virtual biliary, liver and Tip from CT are overlapped to the corresponding position of the patient for dynamic virtual-real fusion.

RESULTS

Our system is respectively evaluated and achieved an average alignment error of 0.75 ± 0.17 mm and 2.79 ± 0.46 mm on phantoms and patients. The navigation experiments conducted on phantoms achieve an average Tip positioning error of 0.98 ± 0.15 mm and an average fusion error of 1.67 ± 0.34 mm after correction.

CONCLUSION

Our system can automatically register the Tip to the corresponding location in CT, and dynamically overlap the 3D virtual model onto patients to provide accurate and intuitive AR navigation.

SIGNIFICANCE

This study demonstrates the clinical potential of our system by assisting physicians during biliary interventional procedures. Our system enables dynamic visualization of virtual model on patients, reducing the reliance on contrast agents and X-ray usage.

Robotic-assisted Navigation Bronchoscopy: A Meta-Analysis of Diagnostic Yield and Complications

BACKGROUND

Robotic-assisted navigation bronchoscopy (RANB) is a novel method to biopsy lung nodules, with initial reports demonstrating excellent accuracy. We aimed to evaluate pooled estimates of diagnostic yields and complication rates with RANB by performing a meta-analysis of the available literature.

METHODS

We searched 3 databases, including PubMed, EmBase, and Web of Science. The resulting abstracts were reviewed by 2 investigators. Analyses were performed using random effects models, and diagnostic yield and complication rates were estimated after the Freeman-Tukey transformation.

RESULTS

A total of 23 articles, comprising 1409 patients and 1541 nodules, were included in the final analysis. Mean ages ranged from 63.2 to 69.3 years. The average size of the nodules ranged between 5.9 and 25.0 mm. Most patients (54.0% to 92.0%) had a current or prior smoking history in studies that reported them (n=8). The pooled diagnostic yield was 81.9% (12 studies, 838 nodules, 95% CI: 83.4%-91.0%), and the pooled sensitivity for malignancy was 87.6% (8 studies, 699 nodules, 95% CI: 81.3%-89.5%). The pooled incidence of pneumothorax rates was 0.60% (95% CI: 0.11%-1.35%). The pooled incidence of major bleeding was <0.01%.

CONCLUSION

Diagnostic yield for patients with pulmonary nodules undergoing RANB is high, though may be impacted by the prevalence of malignancy, participant selection, and publication bias. Complication rates, including pneumothoraces and bleeding rates, appear low across all studies. If RANB is available, clinicians should consider utilizing this platform to biopsy pulmonary nodules.

The effect of combining different sampling tools on the performance of electromagnetic navigational bronchoscopy for the evaluation of peripheral lung lesions and factors associated with its diagnostic yield

BACKGROUND

We assessed the performance of Electromagnetic navigational bronchoscopy (ENB) as a standalone diagnostic technique and the performance of different sampling tools used during the procedure.

METHODS

We recruited 160 consecutive patients who underwent ENB for peripheral lung lesions (PLL) at a tertiary care centre. The diagnostic performance of ENB and sampling tools was assessed using a logistic regression model and a ROC-curve in which the dependent variable was diagnostic success. A multivariate model was built to predict diagnostic success before performing ENB to select the best candidates for the procedure.

RESULTS

Most patients with PLLs in the study were male (65%), with a mean age of 67.9 years. The yield was 66% when the most common techniques were used together as suction catheter + transbronchial biopsy forceps (TBBx) + bronchoalveolar lavage + bronchial washing (p < 0.001) and increased to 69% when transbronchial needle aspiration (TBNA) and cytology brush were added (p < 0.001). Adding diagnostic techniques such as TBBx and TBNA resulted in an increase in diagnostic performance, with a statistically significant trend (p = 0.002). The logistic model area-under the ROC-curve for diagnostic success during ENB was 0.83 (95% CI:0.75-0.90; p < 0.001), and a logit value ≥ 0.12 was associated with ≥ 50% probability of diagnostic success.

CONCLUSIONS

ENB, as a stand-alone diagnostic tool for the evaluation of PLLs when performed by experienced operators using a multi-modality technique, has a good diagnostic yield. The probability of having a diagnostic ENB could be assessed using the proposed model.

A novel approach to wireless electromagnetic tracking using frequency modulation radio communication

PURPOSE

Electromagnetic tracking (EMT) is beneficial in image-guided interventions to reduce the use of ionising radiation-based imaging techniques. Enabling wirelessly tracked sensors will increase the usability of these systems for catheter tracking and patient registration systems. This work introduces a novel method of wirelessly transmitting sensor data using a frequency modulation (FM) radio.

METHODS

The proposed technique was tested using the open-source Anser EMT system. An electromagnetic sensor was connected in parallel to an FM transmitter prototype and wired directly to the Anser system for comparison. The performance of the FM transmitter was evaluated on a grid of 125 test points using an optical tracking system as a gold standard.

RESULTS

An average position accuracy of 1.61 ± 0.68 mm and angular rotation accuracy of 0.04° for the FM transmitted sensor signal was obtained over a 30 cm × 30 cm × 30 cm volume, in comparison with the 1.14 ± 0.80 mm, 0.04° accuracy previously reported for the Anser system. The FM transmitted sensor signal had an average resolved position precision of 0.95 mm while the directly wired signal was found to have an average precision of 1.09 mm. A very low frequency (∼ 5 mHz) oscillation in the wirelessly transmitted signal was observed and compensated for by performing a dynamic scaling of the magnetic field model used for solving the sensor pose.

CONCLUSIONS

We demonstrate that FM transmission of an electromagnetic sensor signal can be used to achieve similar tracking performance to a wired sensor. FM transmission for wireless EMT is a viable alternative to digital sampling and transmission over Bluetooth. Future work will create an integrated wireless sensor node using FM communication that is compatible with existing EMT systems.

Digital Tomosynthesis: Review of Current Literature and Its Impact on Diagnostic Bronchoscopy

Bronchoscopy has garnered increased popularity in the biopsy of peripheral lung lesions. The development of navigational guided bronchoscopy systems along with radial endobronchial ultrasound (REBUS) allows clinicians to access and sample peripheral lesions. The development of robotic bronchoscopy improved localization of targets and diagnostic accuracy. Despite such technological advancements, published diagnostic yield remains lower compared to computer tomography (CT)-guided biopsy. The discordance between the real-time location of peripheral lesions and anticipated location from preplanned navigation software is often cited as the main variable impacting accurate biopsies. The utilization of cone beam CT (CBCT) with navigation-based bronchoscopy has been shown to assist with localizing targets in real-time and improving biopsy success. The resources, costs, and radiation associated with CBCT remains a hindrance in its wider adoption. Recently, digital tomosynthesis (DT) platforms have been developed as an alternative for real-time imaging guidance in peripheral lung lesions. In North America, there are several commercial platforms with distinct features and adaptation of DT. Early studies show the potential improvement in peripheral lesion sampling with DT. Despite the results of early observational studies, the true impact of DT-based imaging devices for peripheral lesion sampling cannot be determined without further prospective randomized trials and meta-analyses.

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.

A Millimeter-Scale Soft Robot for Tissue Biopsy Procedures

While interest in soft robotics as surgical tools has grown due to their inherently safe interactions with the body, their feasibility is limited in the amount of force that can be transmitted during procedures. This is especially apparent in minimally invasive procedures where millimeter-scale devices are necessary for reaching the desired surgical site, such as in interventional bronchoscopy. To leverage the benefits of soft robotics in minimally invasive surgery, a soft robot with integrated tip steering, stabilization, and needle deployment capabilities is proposed for lung tissue biopsy procedures. Design, fabrication, and modeling of the force transmission of this soft robotic platform allows for integration into a system with a diameter of 3.5 mm. Characterizations of the soft robot are performed to analyze bending angle, force transmission, and expansion during needle deployment. In-vitro experiments of both the needle deployment mechanism and fully integrated soft robot validate the proposed workflow and capabilities in a simulated surgical setting.

Comparative analysis of the efficacy and safety of electromagnetic navigation bronchoscopy combined with x-ray or radial endobronchial ultrasound biopsy in the diagnosis of small peripheral pulmonary nodules

OBJECTIVE

To compare the clinical value and safety of electromagnetic navigation bronchoscopy (ENB) combined with radial endobronchial ultrasound (R-EBUS) or x-ray in the diagnosis of small peripheral pulmonary nodules that cannot be diagnosed by conventional bronchoscopy.

METHODS

Fifty-six patients with peripheral pulmonary nodules of <3 cm in diameter who underwent bronchoscopy at the First Affiliated Hospital of Soochow University and Dushu Lake Hospital of Soochow University from February 2019 to January 2022 were selected as the study subjects, including 24 patients who underwent ENB combined with x-ray and 32 patients who underwent ENB combined with R-EBUS. ENB was used as the guiding method in both groups, and x-ray group and R-EBUS group were combined with x-ray and R-EBUS, respectively, to determine whether the lesion was reached. In x-ray group, biopsy and brushing were performed under fluoroscopic guidance. Using the results of surgery, puncture pathology, or clinical follow-up 1 year as the gold standard, the diagnostic sensitivity, specificity, negative predictive value (NPV), diagnostic yield, negative likelihood ratio (LR-), Youden index, missed diagnosis rate, success rate, and κ value were compared between the two groups, and the occurrence of postoperative complications was also compared between the two groups.

RESULTS

The negative predictive value of the R-EBUS group was significantly better than that of the x-ray group (p = 0.006).

CONCLUSION

Even with smaller nodule diameters, the negative predictive value of ENB combined with R-EBUS were still higher than that of the x-ray group.

Diagnostic Performance of Electromagnetic Navigation versus Virtual Navigation Bronchoscopy-Guided Biopsy for Pulmonary Lesions in a Single Institution: Potential Role of Artificial Intelligence for Navigation Planning

Navigation bronchoscopy is an emerging technique used to evaluate pulmonary lesions. Using Veran’s SPiN electromagnetic navigation bronchoscopy (ENB) and Archimedes virtual bronchoscopy navigation (VBN), this study aimed to compare the accuracy and safety of these procedures for lung lesions and to identify potentially relevant knowledge for the application of artificial intelligence in interventional pulmonology in a single institute. This single-center, retrospective study compared the ENB and VBN results in patients with pulmonary lesions unsuitable for biopsy via percutaneous transthoracic needle biopsy methods. A total of 35 patients who underwent navigation bronchoscopy for pulmonary lesion diagnosis were enrolled. Nineteen patients were stratified in the ENB group, and sixteen were in the VBN group. The mean age of this cohort was 67.6 ± 9.9 years. The mean distance of the lesion from the pleural surface was 16.1 ± 11.7 mm (range: 1.0–41.0 mm), and most lesions were a solid pattern (n = 33, 94.4%). There were 32 cases (91.4%) of pulmonary lesions with an air-bronchus sign. A statistically significant difference was found between pulmonary size and transparenchymal nodule access (p = 0.049 and 0.037, respectively). The navigation success rate was significantly higher in the VBN group (93.8% vs. 78.9%). Moreover, no procedure-related complications or mortality were noted. The radiographic characteristics, such as size or solid component, can affect the selection of the biopsy procedure, either ENB or VBN. Navigation bronchoscopy-guided biopsy demonstrated acceptable accuracy and a good safety profile in evaluating pulmonary lesions when the percutaneous approach was challenging or life threatening.

Measurement Systems for Use in the Navigation of the Cannula-Guide Assembly within the Deep Regions of the Bronchial Tree

BACKGROUND

The purpose of this paper is to present the spatial navigation system prototype for localizing the distal tip of the cannula-guide assembly. This assembly is shifted through the channel of a bronchoscope, which is fixed in relation to the patient. The navigation is carried out in the bronchial tree, based on maneuvers of the aforementioned assembly.

METHODS

The system consists of three devices mounted on the guide handle and at the entrance to the bronchoscope working channel. The devices record the following values: cannula displacement, rotation of the guide handle, and displacement of the handle ring associated with the bending of the distal tip of the guide.

RESULTS

In laboratory experiments, we demonstrate that the cannula displacement can be monitored with an accuracy of 2 mm, and the angles of rotation and bending of the guide tip with an accuracy of 10 and 20 degrees, respectively, which outperforms the accuracy of currently used methods of bronchoscopy support.

CONCLUSIONS

This accuracy is crucial to ensure that we collect the material for histopathological examination from a precisely defined place. It makes it possible to reach cancer cells at their very early stage.

Robotics in the diagnosis and staging of lung cancer

The diagnosis of peripheral small lung lesions by electromagnetic navigational bronchoscopy is still inferior to computed tomography (CT) guided percutaneous transthoracic needle lung biopsy. Robotic bronchoscopy is a new technology that may be a potential breakthrough in the diagnosis of small lung lesions. Real-time tools such as electromagnetic navigation, radial-endobronchial ultrasound, and cone beam CT may further improve the diagnostic yield rate may further improve the diagnostic yield rate. In this article, we reviewed early experience of robotic bronchoscopy for diagnosis and staging of lung cancer.

Endoscopic Technologies for Peripheral Pulmonary Lesions: From Diagnosis to Therapy

Peripheral pulmonary lesions (PPLs) are frequent incidental findings in subjects when performing chest radiographs or chest computed tomography (CT) scans. When a PPL is identified, it is necessary to proceed with a risk stratification based on the patient profile and the characteristics found on chest CT. In order to proceed with a diagnostic procedure, the first-line examination is often a bronchoscopy with tissue sampling. Many guidance technologies have recently been developed to facilitate PPLs sampling. Through bronchoscopy, it is currently possible to ascertain the PPL's benign or malignant nature, delaying the therapy's second phase with radical, supportive, or palliative intent. In this review, we describe all the new tools available: from the innovation of bronchoscopic instrumentation (e.g., ultrathin bronchoscopy and robotic bronchoscopy) to the advances in navigation technology (e.g., radial-probe endobronchial ultrasound, virtual navigation, electromagnetic navigation, shape-sensing navigation, cone-beam computed tomography). In addition, we summarize all the PPLs ablation techniques currently under experimentation. Interventional pulmonology may be a discipline aiming at adopting increasingly innovative and disruptive technologies.

Historical eye: from traditional to endobronchial ultrasound-guided needle aspiration and beyond

PURPOSE OF REVIEW

In the history of bronchoscopy, the advent of flexible transbronchial needle aspiration (TBNA) before and, subsequently, of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), have represented fundamental events, as they have significantly and definitively changed interventional pulmonology's role in diagnostic and therapeutic work-up of most of thoracic diseases.Purpose of this historical review is to retrace the main stages that have contributed to the development of these two techniques.

RECENT FINDINGS

TBNA allowed the bronchoscopists to overcome the barrier of the tracheobronchial wall and to obtain samples from hilar-mediastinal lesions. With this additional method, bronchoscopy has become an essential procedure for staging of lung cancer.The advent of echo-bronchoscopes, allowing to perform TBNA under direct ultrasound guidance in real time, further increased the diagnostic yield of this technique. Furthermore, the insertion of the echo-bronchoscope through the oesophagus allowed to extend the landscape of targets to sample, including also para-esophageal lesions, liver metastases, celiac nodes and left adrenal glands.EBUS-TBNA has shown its usefulness not only in the approach to mediastinal lesions, but also in other clinical conditions, such as lung nodules or masses adjacent to the tracheobronchial tree.

SUMMARY

Despite the obvious advantages of EBUS-TBNA, this technology is not yet available in many centres and countries worldwide. For this reason, TBNA remains a basic technique that must complete the technical background of bronchoscopists and it should not be forgotten.

When Pulmonologists Are Novice to Navigational Bronchoscopy, What Predicts Diagnostic Yield?

Predicting factors of diagnostic yield in electromagnetic navigation bronchoscopy (ENB) have been explored in a number of previous studies based on data from experienced operators. However, little is known about predicting factors when the procedure is carried out by operators in the beginning of their learning curve. We here aim to identify the role of operators' experience as well as lesion- and procedure characteristics on diagnostic yield of ENB procedures in the hands of novice ENB operators. Four operators from three centers without prior ENB experience were enrolled. The outcome of consecutive ENB procedures was assessed and classified as either diagnostic or non-diagnostic and predicting factors of diagnostic yield were assessed. A total of 215 procedures were assessed. A total of 122 (57%) of the ENB procedures resulted in diagnostic biopsies. Diagnostic ENB procedures were associated with a minor yet significant difference in tumor size compared to non-diagnostic/inconclusive ENB procedures (28 mm vs. 24 mm; p = 0.03). Diagnostic ENB procedures were associated with visible lesions at either fluoroscopy (p = 0.003) or radial endobronchial ultrasound (rEBUS), (p = 0.001). In the logistic regression model, lesion visibility on fluoroscopy, but none of operator experience, the presence of a bronchus sign, lesion size, or location nor visibility on rEBUS significantly impacted the diagnostic yield. In novice ENB operators, lesion visibility on fluoroscopy was the only factor found to increase the chance of obtaining a diagnostic sample.

Shape-Sensing Robotic-Assisted Bronchoscopy vs Digital Tomosynthesis-Corrected Electromagnetic Navigation Bronchoscopy: A Comparative Cohort Study of Diagnostic Performance

BACKGROUND

Electromagnetic navigational bronchoscopy has been the dominant bronchoscopic technology for targeting small peripheral lesions and now includes digital tomosynthesis-electromagnetic navigational bronchoscopy (DT-ENB), allowing near-real-time intraprocedural nodule visualization. Shape-sensing robotic-assisted bronchoscopy (ssRAB), with improved catheter stability and articulation recently became available. Although the diagnostic performance of these two methods seems higher than that of legacy systems, data remain limited. We sought to compare the diagnostic yield of these two novel platforms after their introduction at our institution.

RESEARCH QUESTION

Does the diagnostic yield of ssRAB differ significantly from that of DT-ENB in patients undergoing biopsy of peripheral pulmonary lesions (PPLs)?

STUDY DESIGN AND METHODS

This retrospective comparative cohort study analyzed prospectively collected data on consecutive procedures performed with DT-ENB and ssRAB in their first 6 months of use at our institution. Biopsies were considered diagnostic if histopathologic analysis revealed malignancy or specific benign features that readily explained the presence of a PPL. Nonspecific inflammation, normal lung or airway, and atypia not diagnostic of malignancy were considered nondiagnostic.

RESULTS

SSRAB was used to biopsy 143 PPLs in 133 patients and DT-ENB was used to biopsy 197 PPLs in 170 patients. Diagnostic yield was 77% for ssRAB (110 of 143 PPLs) and 80% (158 of 197 PPLs) for DT-ENB (OR, 0.8; 95% CI, 0.5-1.4; P = .4). Median lesion diameters were 17 and 19 mm, respectively. No difference in diagnostic yield was found after adjustment for lesion size, bronchus sign, peripheral vs middle third location, and sex. Pneumothorax complicated 1.5% of ssRAB and 1.8% of DT-ENB procedures (P = .86).

INTERPRETATION

SSRAB and DT-ENB showed comparable diagnostic yields and safety profiles in this comparative cohort study.

Learning Curves for Electromagnetic Navigation Bronchoscopy Using CUSUM Analysis

BACKGROUND

Electromagnetic navigation bronchoscopy (ENB) is a relatively new and technically demanding procedure for the guidance of bronchoscopic biopsy to help locate small lung lesions. The results in experienced hands are well described. However, we do not know the results in unexperienced hands-in other words, we have no knowledge about how fast you can learn the procedure.

AIM

The aim of this study was to draw learning curves for beginners in ENB using Cumulated Sum (CUSUM) analysis, a method for quantitative evaluation of the learning curves for clinical procedures.

METHODS

Four operators from 3 centers without prior ENB experience were enrolled. The outcome of consecutive ENB procedures was assessed and classified as either diagnostic or nondiagnostic based on sample adequacy. Learning curves were drawn based on diagnostic yield.

RESULTS

A total of 215 procedures were assessed. For 2 of the operators (operators 1 and 4), at least 25 to 30 procedures were necessary to obtain competency whereas operators 2 and 3 showed more horizontal learning curves indicating an overweight of diagnostic procedures from the beginning.

CONCLUSION

Operators achieve competences in ENB at different paces. This must be taken in account when beginners start to learn the procedure. There is a huge need for a structured educational program and a validated test to determine competences.

[Application and Progress of Electromagnetic Navigation Bronchoscopy in Department of Thoracic Surgery]

Lung cancer ranks the first cancer-related morbidity and mortality in China. With the development and penetration of imaging technology, increasing small pulmonary peripheral Nodules (SPPNs) have been detected. However, precise location and diagnosis of SPPNs is still a tough problem for clinical diagnosis and treatment in department of thoracic surgery. With the development of electromagnetic navigation bronchoscopy (ENB), it provides a novel minimally invasive method for the diagnosis and treatment of SPPNs. In this review, we summarized the application and progress of ENB in preoperative positioning, diagnosis, and local treatment, then, discussed the clinical application of ENB in the hybrid operating room.
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Augmented reality-assisted localization of solitary pulmonary nodules for precise sublobar lung resection: a preliminary study using an animal model

Background

Accurate localization of early lung cancer, manifested as solitary pulmonary nodules (SPNs) on computed tomography (CT), is critical in sublobar lung resection. The AR-assisted localization of SPNs was evaluated using a pig animal model.

Methods

A Microsoft HoloLens AR system was used. First, a plastic thoracic model was used for the pilot study. Three female 12 months 45 kg Danish Landrace Pigs were then used for the animal study. Thirty natural pulmonary structures, such as lymphonodus and bifurcated bronchioles or bronchial vessels, were chosen as simulated SPNs. The average angle between the actual puncturing needle and the expected path, the average distance between the puncture point and the plan point, and the difference between the actual puncturing depth and expected depth were recorded, and the accuracy rate was calculated.

Results

The point selected in the plastic thoracic model could be hit accurately with the assistance from the AR system in the pilot study. Moreover, the average angle between the actual puncturing needle and the expected path was 14.52°±6.04°. Meanwhile, the average distance between the puncture point and the expected point was 8.74±5.07 mm, and the difference between the actual and expected depths was 9.42±7.95 mm. Puncturing within a 1 cm³ area around the SPN using a hook-wire was considered a successful hit. The puncture accuracy was calculated. The average hit rate within a spherical area with a diameter of 1 cm range was 76.67%, and within a diameter of 2 cm range was 100%.

Conclusions

The HoloLens AR-assisted localization of SPNs may become a promising technique to improve the surgical treatment of early-stage lung cancer. Here, we evaluated its feasibility in an animal model. Nevertheless, its safety and effectiveness require further investigation in clinical trials.

Advances in Diagnostic Bronchoscopy

The increase in incidental discovery of pulmonary nodules has led to more urgent requirement of tissue diagnosis. The peripheral pulmonary nodules are especially challenging for clinicians. There are various modalities for diagnosis and tissue sampling of pulmonary lesions, but most of these modalities have their own limitations. This has led to the development of many advanced technical modalities, which have empowered pulmonologists to reach the periphery of the lung safely and effectively. These techniques include thin/ultrathin bronchoscopes, radial probe endobronchial ultrasound (RP-EBUS), and navigation bronchoscopy—including virtual navigation bronchoscopy (VNB) and electromagnetic navigation bronchoscopy (ENB). Recently, newer technologies—including robotic-assisted bronchoscopy (RAB), cone-beam CT (CBCT), and augmented fluoroscopy (AF)—have been introduced to aid in the navigation to peripheral pulmonary nodules. Technological advances will also enable more precise tissue sampling of smaller peripheral lung nodules for local ablative and other therapies of peripheral lung cancers in the future. However, we still need to overcome the CT-to-body divergence, among other limitations. In this review, our aim is to summarize the recent advances in diagnostic bronchoscopy technology.

Electromagnetic navigational bronchoscopy-guided dye marking to identify the subsegmental bronchus in thoracoscopic anatomic subsegmentectomy

Video‐assisted thoracoscopic surgery (VATS) subsegmentectomy has been widely used to resect small‐sized lung lesions in clinical practice. Precise identification of the subsegmental bronchus is one of the essential steps in performing thoracoscopic anatomic subsegmentectomy. Here, we report a thoracoscopic right S²a segmentectomy with preoperative electromagnetic navigational bronchoscopy (ENB)‐guided injection of methylene blue to identify the subsegmental bronchus in a 51‐year‐old male. We successfully performed complicated surgery using this method. This ENB‐guided dye marking method may accurately distinguish the subsegmental bronchus to effectively guide surgery.

Multi-Dimensional Display of Wang's Lymph Node Map Using Virtual Bronchoscopic Navigation System

Background: Transbronchial needle aspiration (TBNA) is a classical technique for diagnosing mediastinal-hilar lymph node enlargement. However, the diagnostic value of conventional TBNA (cTBNA) is limited in small lymph nodes.

Methods: Here, we generated an innovative multi-dimensional virtual lymph node map on top of Wang’s lymph node map using a Lungpoint Virtual Bronchoscopic Navigation System.

Results: The virtual bronchoscopic navigation (VBN) system was combined with computed tomography (CT) images to generate extrabronchial, endobronchial, sagittal, coronal as well as horizontal views of the 11 intrathoracic lymph node stations and their adjacent tissues and blood vessels. We displayed the specific puncture site of each lymph node station. The 11 stations were divided into four groups: right mediastinal stations, left mediastinal stations, central mediastinal stations and hilar stations.

Conclusion: The VBN system provides a precise view of the intrabronchial landmarks, which may increase the diagnostic accuracy of intrathoracic lymph node adenopathy and assist bronchoscopists with practicing TBNA.

Invasive modalities for the diagnosis of peripheral lung nodules

INTRODUCTION

Lung nodules are being increasingly discovered either incidentally or through lung cancer screening chest CT scans. Some of these will turn out to be malignant and therefore it is important to obtain an accurate and timely diagnosis of lung cancer when suspected.

AREAS COVERED

This review will cover various invasive diagnostic modalities available to sample lung nodules. Data from key studies, obtained from PubMed searches, will be reviewed. Emerging technologies such as cone-beam CT and robotic-assisted bronchoscopies will be discussed along with ddata available currently to support their use.

EXPERT OPINION

The best approach to diagnosing a lung nodule - whether found incidentally or because of lung cancer screening - is continuously evolving. While CT-guided lung nodule biopsy has a high diagnostic yield, the risk of pneumothorax is often a concern. Bronchoscopy has a better safety profile, but diagnostic ability falls short of CT-guided biopsy. Existing technologies such as electromagnetic navigation have not demonstrated a high diagnostic yield. Factors responsible for this relatively lower low diagnostic yield will be discussed in detail. Emerging technologies such as cone-beam CT scan and robotic bronchoscopy have addressed some of these issues and initial experience has demonstrated better diagnostic yield.

Bronchoscope motion tracking using centerline-guided Gaussian mixture model in navigated bronchoscopy

Electromagnetic-based navigation bronchoscopy requires accurate and robust estimation of the bronchoscope position inside the bronchial tree. However, respiratory motion, coughing, patient movement, and airway deformation inflicted by bronchoscope significantly hinder the accuracy of intraoperative bronchoscopic localization. In this study, a real-time and automatic registration procedure was proposed to superimpose the current location of the bronchoscope to corresponding locations on a centerline extracted from bronchial computed tomography (CT) images. A centerline-guided Gaussian mixture model (CG-GMM) was introduced to register a bronchoscope's position concerning extracted centerlines. A GMM was fitted to bronchoscope positions where the orientation likelihood was chosen to assign the membership probabilities of the mixture model, which led to preserving the global and local structures. The problem was formulated and solved under the expectation maximization framework, where the feature correspondence and spatial transformation are estimated iteratively. Validation was performed on a dynamic phantom with four different respiratory motions and four human real bronchoscopy (RB) datasets. Results of the experiments conducted on the bronchial phantom showed that the average positional tracking error using the proposed approach was equal to 1.98 [Formula: see text] 0.98 mm that was reduced in comparison with independent electromagnetic tracking (EMT), iterative closest point (ICP), and coherent point drift (CPD) methods by 64%, 58%, and 53%, respectively. In the patient assessment part of the study, the average positional tracking error was 4.73 [Formula: see text] 4.76 mm and compared to ICP, and CPD methods showed 31.4% improvement of successfully tracked frames. Our approach introduces a novel method for real-time respiratory motion compensation that provides reliable guidance during bronchoscopic interventions and, thus could increase the diagnostic yield of transbronchial biopsy.

The Diagnostic Accuracy and Sensitivity for Malignancy of Radial-Endobronchial Ultrasound and Electromagnetic Navigation Bronchoscopy for Sampling of Peripheral Pulmonary Lesions: Systematic Review and Meta-analysis

BACKGROUND

Lung cancer screening with computed tomography chest is identifying peripheral pulmonary lesions (PPLs) suspicious for early-stage lung cancer at increasing rates. Radial-endobronchial ultrasound (R-EBUS) and electromagnetic navigation bronchoscopy (ENB) are 2 methods to sample PPLs to diagnose and treat early lung cancer. ENB has a higher operating financial cost, however, the rationale for its use is possible higher diagnostic accuracy versus R-EBUS.

OBJECTIVE

The objective of this study was to determine the comparative diagnostic accuracy, sensitivity, and negative predictive value for R-EBUS and ENB in sampling PPLs.

METHODS

A systematic review and meta-analysis were conducted. The Ovid Medline database was queried for original research reporting a diagnostic yield of R-EBUS or ENB for PPLs identified on computed tomography chest suspicious for malignancy. The I statistic assessed study heterogeneity. Random effects models produced pooled estimates of diagnostic accuracy and sensitivity for malignancy. Reasons for heterogeneity were explored with meta-regression. Publication bias and small study effects were assessed.

RESULTS

A total of 41 studies involved 2988 lung nodules (R-EBUS 2102, ENB 886) in 3204 patients (R-EBUS 2097, ENB 1107). Overall sensitivity to detect cancer was 70.7% [95% confidence interval (CI): 67.2-74.0]; R-EBUS 70.5% (95% CI: 66.1-74.8), ENB 70.7% (95% CI: 64.7-76.8). Pooled overall diagnostic accuracy was 74.2% (95% CI: 71.0-77.3); R-EBUS 72.4% (95% CI: 68.7-76.1), ENB 76.4% (95% CI: 70.8-82.0). The localization modalities had comparative safety profiles of <2% complications.

CONCLUSION

Both technologies have a high proportion of successful PPL localization with similar sensitivity for malignancy and accuracy. As such, both reasonable options for health care authorities to employ diagnostic algorithms.

State of the Art: Robotic Bronchoscopy

Increased detection of lung nodules has led to trying to improve technologies for localization and/or tissue acquisition. Previous bronchoscopic techniques have limitations that have led to further advancements in technology. Robotic bronchoscopy has emerged as new technology for the localization, diagnosis, and potential treatment of lung nodules. The robotic bronchoscopic platform was developed to improve peripheral reach of lung nodules, provide direct continuous visualization of the periphery, and offer more precise control of the instrumentation. We review the progression of bronchoscopy, evolution to the robotic platform and its early outcomes, with considerations for future advancements.

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.

Three-dimensional printed navigational template for localizing small pulmonary nodules: A case-controlled study

Background

Localization of small pulmonary nodules is an inevitable challenge for the thoracic surgeon. This study aimed to investigate the accuracy of three‐dimensional (3D) printing technology for localizing small pulmonary nodules, especially ground‐glass nodules (GGNs).

Methods

This study enrolled patients with peripheral small pulmonary nodules (≤ 2 cm) who required preoperative localization. In the comparison period, patients underwent both computed tomography‐guided (CT‐G) and 3D‐printing template guided (3D‐G) localization to compare the accuracies of the two methods. In the testing period, the 3D‐printing technique was implemented alone. The 3D‐printing physical navigational template was designed based on data from perioperative CT images. Clinical data, imaging data, surgical data, and evaluation index were collected for further analysis. The learning curve of the 3D‐printing localization technique was assessed using cumulative sum (CUSUM) analysis and multiple linear regression analysis.

Results

In the comparison period (n = 14), the success rates of CT‐G and 3D‐G were 100% and 92.9% (P = 0.31), respectively; in the testing period (n = 23), the success rate of 3D‐G was 95.6%. The localization times of CT‐G, 3D‐G (comparison), and 3D‐G (testing) were 23.6 ± 5.3, 19.3 ± 6.8, and 9.8 ± 4.6 minutes, respectively. The CUSUM learning curve was modeled using the equation: Y = 0.48X²− 0.013X − 0.454 (R² = 0.89). The learning curve was composed of two phases, phase 1 (the initial 20 patients) and phase 2 (the remaining 17 patients).

Conclusions

3D printing localization has adequate accuracy and is a feasible and accessible strategy for use in localizing small pulmonary nodules, especially in right upper lobe. The use of this technique could facilitate lung nodule localization prior to surgery.

Jet Ventilation Decreases Target Motion and Increases Yield of ENB Especially in Lesions With Negative Bronchus Sign

BACKGROUND

Electromagnetic navigational bronchoscopy (ENB) is used to obtain peripheral lung tissue samples for evaluation and staging of central and peripheral lung lesions. Jet ventilation delivers and maintains a sustained airway pressure at high frequency, chest wall and diaphragmatic movement is drastically reduced compared with traditional ventilation. The current study looks to examine the effectiveness of tissue sampling (diagnostic yield) while using jet ventilation on target-lesion movement when compared with traditional ventilation.

METHODS

A total of 36 patients received total intravenous anesthesia with both jet and traditional ventilation during ENB procedure where sensor to lesion displacement was recorded. When planning the ENB procedure, the presence or absence of a viable airway to the lesion was recorded. Sensor to lesion movement was recorded and compared for significance using χ and t tests, utilizing stringent P-values.

RESULTS

Overall patients with an airway to the lesion (n=23) had a higher proportion of successful diagnostic biopsies, 83% compared with those patients that lacked an airway to the lesion (n=13) 70% proportion of successful diagnostic biopsies. When using jet ventilation, the chance of nonzero displacement was 8.3% (0.14 mm), regardless of the presence of an airway. Compared with traditional ventilation, the chance of a nonzero displacement between the sensor and target-lesion was 83% (6.4 mm), independent of airway presence to the lesions.

CONCLUSION

In patients without an airway, jet ventilation significantly decreased target displacement when compared with traditional ventilation (2 vs. 17 mm). In patients with direct airway to the lesion, jet ventilation did not significantly decrease target displacement when compared with the traditional approach.

Navigational bronchoscopy: a guide through history, current use, and developing technology

The peripheral pulmonary nodule offers unique challenges to the clinician, especially in regards to diagnostic approach. Quite often the etiology of the nodule is spurious, though the specter of malignancy drives accurate classification of the nodule. Diagnostic approaches range in degrees of invasiveness, accuracy, and morbidity. Bronchoscopic access to these nodules had been plagued by low reported yields, especially in fluoroscopically invisible nodules. Navigational bronchoscopy, however, allowed more accurate access to peripheral nodules while maintaining a low morbidity, and thus reshaped the historic diagnostic algorithms. Though navigational bronchoscopy was initially associated with electromagnetic navigation, newer approaches to navigation and new technologies provide enthusiasm that yield can improve. In this article we will provide a historical approach to navigational bronchoscopy, from its origins to its current state, and we will discuss developing technology and its potential role in the evolving paradigm of the peripheral nodule biopsy.

Sensitivity and Safety of Electromagnetic Navigation Bronchoscopy for Lung Cancer Diagnosis: Systematic Review and Meta-analysis

BACKGROUND

Bronchoscopy is a useful tool for the diagnosis of lesions near central airways; however, the diagnostic accuracy of these procedures for peripheral pulmonary lesions (PPLs) is a matter of ongoing debate. In this setting, electromagnetic navigation bronchoscopy (ENB) is a technique used to navigate and obtain samples from these lesions. This systematic review and meta-analysis aims to explore the sensitivity of ENB in patients with PPLs suspected of lung cancer.

RESEARCH QUESTION

In patients with peripheral pulmonary lesion suspected of lung cancer, what is the sensitivity and safety of electromagnetic navigation bronchoscopy compared to surgery or longitudinal follow up?

STUDY DESIGN AND METHODS

A comprehensive search of several databases was performed. Extracted data included sensitivity of ENB for malignancy, adequacy of the tissue sample, and complications. The study quality was assessed using the QUADAS-2 tool, and the combined data were meta-analyzed using a bivariate method model. A summary receiver operatic characteristic curve (sROC) was created. Finally, the quality of evidence was rated using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Forty studies with a total of 3,342 participants were included in our analysis. ENB reported a pooled sensitivity of 77% (95% CI, 72%-82%; I² = 80.6%) and a specificity of 100% (95% CI, 99%-100%; I² = 0%) for malignancy. The sROC showed an area under the curve of 0.955 (P = .03). ENB achieved a sufficient sample for ancillary tests in 90.9% (95% CI, 84.8%-96.9%; I² = 80.7%). Risk of pneumothorax was 2.0% (95% CI, 1.0-3.0; I² = 45.2%). We found subgroup differences according to the risk of bias and the number of sampling techniques. Meta-regression showed an association between sensitivity and the mean distance of the sensor tip to the center of the nodule, the number of tissue sampling techniques, and the cancer prevalence in the study.

INTERPRETATION

ENB is very safe with good sensitivity for diagnosing malignancy in patients with PPLs. The applicability of our findings is limited because most studies were done with the superDimension navigation system and heterogeneity was high.

TRIAL REGISTRY

PROSPERO; No.: CRD42019109449; URL: https://www.crd.york.ac.uk/prospero/.

[Clinical Application of Vectorial Localization of Peripheral Pulmonary Nodules Guided by Electromagnetic Navigation Bronchoscopy in Thoracic Surgery]

背景与目的

随着计算机断层扫描技术（computed tomography scans, CT）的广泛应用，越来越多的肺小结节被发现，一些需要外科手术处理的结节数量也在增加。胸腔镜手术中对于不可直视及触摸到的肺外周小结节的准确定位较为困难。虽然目前一些常用的定位技术能够带来比较好的定位效果，如CT引导的穿刺定位和电磁导航支气管镜（electromagnetic navigation bronchoscopy, ENB）系统引导的亚甲兰染色定位，但同时仍存在着气胸、出血及定位不准确的问题。ENB引导的矢量定位法是我中心首创的一种新型定位技术，该技术避免了前两种

方法

可能出现的胸膜损伤或者定位区域扩大的问题，为ENB引导的定位技术提供了一定的指导。本文回顾性分析胸腔镜术前通过ENB引导矢量定位的临床结果来确定该方法的临床应用价值。方法回顾性分析2017年10月-2018年10月于青岛大学附属医院胸外科行ENB矢量定位法进行胸腔镜手术前定位的患者资料，统计患者临床资料、肺小结节影像学特征，评估该方法临床应用的安全性及有效性。

结果

我们成功实施了22例患者的22个肺外周结节在ENB引导下矢量定位和腔镜下楔形切除（22/22, 100%）。结节平均大小为（11.0±3.6）mm，距脏层胸膜表面距离为（16.5±6.2）mm；ENB系统显示屏导航定位装置（locatable guide, LG）与病灶距离为（14.5±10.1）mm，离体标本标记与病灶距离为（15.3±11.0）mm，ENB矢量定位平均时间为（17.5±4.2）min，无定位点LG发生移位（0.0%）。手术过程无中转开胸（0.0%），患者术中及术后未见明显并发症（0.0%），术后平均住院时间为（3.8±1.2）d，无围手术期患者死亡（0.0%）。术后病理结果为恶性肿瘤者19例，均得到了完全切除。

结论

我们应用ENB引导的矢量定位法在肺外周小结节术前定位和微创切除的初步经验提示该方法安全、可行、有效，可作为ENB操作中可选的一种定位方式。胸外科临床医师可以进一步研究该方法并应用到临床操作中。

Clinical experience with lung-specific electromagnetic transponders for real-time tumor tracking in lung stereotactic body radiotherapy

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7 patients were implanted with lung-specific electromagnetic transponders (EMT).

•

We report no complications from implantation and no migration of the EMT.

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7 non-small cell lung cancer patients underwent SBRT using EMT real-time tracking.

•

SBRT was delivered in free-breathing (FB) or in deep inspiration breath-hold (DIBH).

Background and purposes

Motion management is crucial for optimal stereotactic body radiotherapy (SBRT) of moving targets. We aimed to describe our clinical experience with real-time tracking of lung-specific electromagnetic transponders (EMTs) for SBRT of early stage non-small cell lung cancer in free-breathing (FB) or deep inspiration breath-hold (DIBH).

Material and methods

Seven patients were implanted with EMTs. Simulation for SBRT was performed in FB and in DIBH. We prescribed 60 Gy in 3, 5 or 8 fractions to the tumor and delivered SBRT with volumetric modulated arcs and a 6 MV flattening filter free photon beam. Patients’ setup at the linac was performed using EMT positions and cone-beam CT (CBCT) verification. Four patients were treated in DIBH because of a dosimetric benefit. We analysed patient alignment and treatment delivery parameters using DIBH or FB and EMT real-time tracking.

Results

There were no complications from the EMT implantation. Visual inspection of CBCT before and/or after SBRT revealed good alignment of structures and EMTs. The median setup time was 9.8 min (range: 4.6–34.1 min) and the median session time was 14.7 min (range: 7.3–36.5 min). EMT positions in lungs remained stable during overall treatment and allowed real-time tracking both in FB and in DIBH SBRT. The treatment beam was gated when EMT centroid position exceeded tolerance thresholds ensuring correct delivery of radiation to the tumor.

Conclusion

Using EMTs for real-time tracking of tumor motion during lung SBRT proved to be safe, accurate and easy to integrate clinically for treatments in FB or DIBH.

Transbronchial biopsy of peripheral lung lesions using fluoroscopic guidance combined with an enhanced ray-summation display

The aim of this study was to investigate the effectiveness of guidance assistance during transbronchial biopsy (TBB) to achieve an appropriate pathway to small and peripheral pulmonary lesions (PPLs) using a combination of fluoroscopy and specialized ray-summation (Ray-sum_TBB) images, which were processed from preprocedural lung computed tomography (CT) images. To improve the visibility of the correct pathway to the PPLs, three-dimensional spatial resolution enhancement and CT number conversion processes were applied to the original CT images. The Ray-sum_TBB images reconstructed from the processed CT images were used as additional guides. We compared the rates of successful tumor localization and biopsy (arrival rate) between the trial (with Ray-sum_TBB) and control (without Ray-sum_TBB) groups. The fluoroscopy and examination times were also compared. The arrival rate of the trial group (73.1%) was significantly better than that of the control group (42.3%) (p = 0.048). The fluoroscopy and examination times did not differ significantly between the trial and control groups. No complications were identified in the trial group. Our results suggest that Ray-sum_TBB improves the diagnostic accuracy of TBB.

Intrinsic properties of medical devices: considerations for economic evaluation

Introduction: In recent decades, medical devices (MDs) have increasingly become an integral part of patient care. However, when it comes to designing and appraising economic models, researchers typically follow pharmaceutical templates (e.g. CHEERS) to assess their economic viability. This study evaluates the generalizability of four device-specific criteria, as recommended by the recent MedtechHTA project, of learning curve, incremental innovation, dynamic pricing, and organizational impact with a broader group of MDs including diagnostics and implantables. The purpose was to determine the applicability of these criteria to a broader range of MDs.Areas Covered: We determined the extent to which these criteria could be applied to each device type and attempted to identify common themes. We performed a literature search using PubMed and Google of a range of devices to understand the clinical significance, operation, and economic viability.Expert Opinion: Our findings suggest that the four characteristics are not applicable to all device types. Prior evaluation of a device's intrinsic properties (such as longevity and device location) and its FDA risk classification could help to indicate the applicability of the criteria. Documenting this process when assessing the additional four criteria on the CHEERS checklist would improve the transparency of future economic evaluations.

Precise sublobar lung resection for small pulmonary nodules: localization and beyond

Early-stage primary lung cancer is increasingly detected by computed tomographic (CT) screening and the radicality of sublobar lung resection (wedge resection and segmentectomy) has been suggested. However, identification of a tumor intraoperatively becomes more difficult, the earlier a nodule is detected. A solution to this challenge is localization techniques. There are many techniques to localize small pulmonary nodules, including that replacing surgeon's tactile sensation, visualizing the tumor using ultrasound, and various types of lung markings that are placed percutaneously under CT guidance or bronchoscopically. The most commonly used technique is CT-guided placement of a hookwire, but there are concerns about potentially fatal air embolism. Bronchoscopic localization, especially using electromagnetic navigation bronchoscopy with or without intraoperative cone-beam CT imaging, has been increasingly reported. Beyond localization, the concept of lung "mapping" is emerging. In sublobar lung resection, in addition to localization of the targeted tumor, acquisition of sufficient resection margins is critical to prevent local recurrence. Virtual-assisted lung mapping (VAL-MAP) has evolved from bronchoscopic dye localization, but by placing multiple dye marks, it provides two-dimensional geometric information on the lung. Moreover, to ensure deep resection margins, the newly developed technique of VAL-MAP 2.0 combining dye marks and intrabronchial placement of a microcoil enables three-dimensional lung mapping. This allows for intraoperative navigation of lung resection under a fluoroscope. Development of this field, such as using a new technology of augmented reality, will further enhance the accuracy and convenience of lung resection in the near future.

Navigation Bronchoscopy

With the advent of lung cancer screening, and the increasingly frequent use of computed tomography (CT) scanning for investigating non-pulmonary pathology (for example CT coronary angiogram), the number of pulmonary nodules requiring further investigation has risen significantly. Most of these nodules are found in the lung periphery, which presents challenges to biopsy, and many centers rely on trans-thoracic needle biopsy performed under image guidance by radiologists. However, the desire to minimize complications is driving the development of increasingly accurate navigation bronchoscopy platforms, something that will be crucial in the new era of bronchoscopic therapeutics for lung cancer. This review describes these platforms, summarizes the current evidence for their use, and takes a look at future developments.