Virtual or reality: divergence between preprocedural computed tomography scans and lung anatomy during guided bronchoscopy

Pulmonary Cytopathology: Current and Future Impact on Patient Care

Small biopsies of lung are routinely obtained by many methods, including several that result in cytologic specimens. Because lung cancer is often diagnosed at a stage for which primary resection is not an option, it is critical that all diagnostic, predictive, and prognostic information be derived from such small biopsy specimens. As the number of available diagnostic and predictive markers expands, cytopathologists must familiarize themselves with current requirements for specimen acquisition, handling, results reporting, and molecular and other ancillary testing, all of which are reviewed here.

Assessing the accuracy of a multisection robotic bronchoscope prototype in localization and targeting of small pulmonary lesions

Objectives

Robotic bronchoscopy (RB) has emerged as a novel technique to address issues with the biopsy of small peripheral lung lesions. The objective of this study was to quantitatively assess the accuracy of a novel multisection robotic bronchoscope compared with current standards of care.

Methods

This is a prospective, single-blind, comparative study where the accuracy of a multisection RB was compared against the accuracy of standard electromagnetic navigational bronchoscopy (EM-NB) during lesion localization and targeting. Five blinded subjects of varying bronchoscopy experience were recruited to use both RB and EM-NB in a swine lung model. Accuracy of localization and targeting success was measured as the distance from the center of pulmonary targets at each anatomic location. Subjects used both RB and EM-NB to navigate to 4 pulmonary targets assigned using 1:1 block randomization. Differences in accuracy and time between navigation systems were assessed using Wilcoxon rank-sum test.

Results

Of the 40 total attempts per modality, successful targeting was achieved on 90% and 85% of attempts utilizing RB and EM-NB, respectively. Furthermore, RB demonstrated significantly lower median distance to the real-time EM target (1.1 mm; interquartile range [IQR], 0.6-2.0 mm) compared with EM-NB (2.6 mm; IQR, 1.6-3.8) (P < .001). Median target displacement resulting from lung and bronchus deformation during bronchoscopy was found to be significantly lower using RB (0.8 mm; IQR, 0.5-1.2 mm) compared with EM-NB (2.6 mm; IQR, 1.4-6.4 mm) (P < .001).

Conclusions

The results of this study demonstrate that the multi-section RB prototype allows for improved localization and targeting of small peripheral lung nodules compared with current nonrobot bronchoscopy modalities.

The incremental contribution of mobile cone-beam computed tomography to the tool-lesion relationship during shape-sensing robotic-assisted bronchoscopy

Introduction

This study aims to answer the question of whether adding mobile cone-beam computed tomography (mCBCT) imaging to shape-sensing robotic-assisted bronchoscopy (ssRAB) translates into a quantifiable improvement in the tool-lesion relationship.

Methods

Data from 102 peripheral lung lesions with ≥2 sequential mCBCT orbital spins and from 436 lesions with 0-1 spins were prospectively captured and retrospectively analysed. The primary outcome was the tool-lesion relationship status across the first and the last mCBCT spins. Secondary outcomes included 1) the change in distance between the tip of the sampling tool and the centre of the lesion between the first and the last spins and 2) the per-lesion diagnostic yield.

Results

Compared to lesions requiring 0-1 spins, lesions requiring ≥2 spins were smaller and had unfavourable bronchus sign and intra-operative sonographic view. On the first spin, 54 lesions (53%) were designated as non-tool-in-lesion (non-TIL) while 48 lesions (47%) were designated as TIL. Of the 54 initially non-TIL cases, 49 (90%) were converted to TIL status by the last spin. Overall, on the last spin, 96 out of 102 lesions (94%) were defined as TIL and six out of 102 lesions (6%) were defined as non-TIL (p<0.0001). The mean distance between the tool and the centre of the lesion decreased from 10.4 to 6.6 mm between the first and last spins (p<0.0001). The overall diagnostic yield was 77%.

Conclusion

Targeting traditionally challenging lung lesions, intra-operative volumetric imaging allowed for the conversion of 90% of non-TIL status to TIL. Guidance with mCBCT resulted in a significant decrease in the distance between the tip of the needle to lesion centre.

Bronchoscopic treatment of early-stage peripheral lung cancer

PURPOSE OF REVIEW

This review article focuses on bronchoscopic treatment of early-stage peripheral lung cancer.

RECENT FINDINGS

Bronchoscopic treatment modalities have garnered considerable attention for early-stage lung cancer. Studies using photodynamic therapy, thermal vapor ablation, laser ablation, cryoablation, and intra-tumoral injection have recently been published. However, the evidence supporting these approaches largely derives from single-arm studies with small sample sizes. Based on the IDEAL-D framework, no technology has progressed passed the idea phase (1). The main weakness of these technologies to date is lack of evidence suggesting they can achieve local control. Presently, no bronchoscopic intervention for lung cancer has sufficient data to warrant its use as part of the standard of care.

SUMMARY

Despite notable progress, current technologies remain suboptimal, and there is insufficient evidence to support their use outside of a research setting.

Incremental Application of Positive End-Expiratory Pressure for the Evaluation of Atelectasis During RP-EBUS and Bronchoscopy (I-APPEAR)

BACKGROUND

CT-to-body divergence-described as the difference between preprocedural CT scans and intraprocedural lung architecture-is a significant barrier to improving diagnostic yield during navigational bronchoscopy. A major proposed contributor to CT-to-body divergence is the development of atelectasis, which can confound visualization of peripheral lung lesions via radial probe endobronchial ultrasound (RP-EBUS). High positive end-expiratory pressure (PEEP) ventilatory strategies have been used to decrease atelectasis, allowing the lesion to re-APPEAR on intraprocedure imaging. However, standardized PEEP levels may not be appropriate for all patients due to hemodynamic and ventilatory impacts.

METHODS

We performed a multicenter, prospective observational study in which patients were imaged with RP-EBUS under general anesthesia to determine if subsegmental atelectasis would resolve as incremental increases in PEEP were applied. Resolution of atelectasis was based on the transition from a non-aerated pattern to an aerated appearance on RP-EBUS. RP-EBUS images were reviewed by 3 experienced operators to determine correlation.

RESULTS

Forty-three patients underwent RP-EBUS examination following navigational bronchoscopy. Thirty-seven patients underwent incremental PEEP application and subsequent RP-EBUS imaging. Atelectasis was determined to have resolved in 33 patients (88.2%) following increased PEEP. The intraclass correlation coefficient between reviewers was 0.76. A recruitment maneuver was performed in 7 (16.3%) patients after atelectasis persisted at maximal PEEP. Atelectasis was not identified in the examined subsegments in 6 (10.8%) patients despite zero PEEP.

CONCLUSION

RP-EBUS is an effective tool to monitor what pressure atelectasis within a lung segment has resolved with increasing levels of PEEP.

Added Value of a Robotic-assisted Bronchoscopy Platform in Cone Beam Computed Tomography-guided Bronchoscopy for the Diagnosis of Pulmonary Parenchymal Lesions

BACKGROUND

Cone beam computed tomography (CBCT)-guided bronchoscopic sampling of peripheral pulmonary lesions (PPLs) is associated with superior diagnostic outcomes. However, the added value of a robotic-assisted bronchoscopy platform in CBCT-guided diagnostic procedures is unknown.

METHODS

We performed a retrospective review of 100 consecutive PPLs sampled using conventional flexible bronchoscopy under CBCT guidance (FB-CBCT) and 100 consecutive PPLs sampled using an electromagnetic navigation-guided robotic-assisted bronchoscopy platform under CBCT guidance (RB-CBCT). Patient demographics, PPL features, procedural characteristics, and procedural outcomes were compared between the 2 cohorts.

RESULTS

Patient and PPL characteristics were similar between the FB-CBCT and RB-CBCT cohorts, and there were no significant differences in diagnostic yield (88% vs. 90% for RB-CBCT, P=0.822) or incidence of complications between the 2 groups. As compared with FB-CBCT cases, RB-CBCT cases were significantly shorter (median 58 min vs. 92 min, P<0.0001) and used significantly less diagnostic radiation (median dose area product 5114 µGy•m2 vs. 8755 µGy•m2, P<0.0001).

CONCLUSION

CBCT-guided bronchoscopy with or without a robotic-assisted bronchoscopy platform is a safe and effective method for sampling PPLs, although the integration of a robotic-assisted platform was associated with significantly shorter procedure times and significantly less radiation exposure.

First-in-human use of a new robotic electromagnetic navigation bronchoscopic platform with integrated Tool-in-Lesion Tomosynthesis (TiLT) technology for peripheral pulmonary lesions: The FRONTIER study

BACKGROUND AND OBJECTIVE

As the presentation of pulmonary nodules increases, the importance of a safe and accurate method of sampling peripheral pulmonary nodules is highlighted. First-generation robotic bronchoscopy has successfully assisted navigation and improved peripheral reach during bronchoscopy. Integrating tool-in-lesion tomosynthesis (TiLT) may further improve yield.

METHODS

We performed a first-in-human clinical trial of a new robotic electromagnetic navigation bronchoscopy system with integrated digital tomosynthesis technology (Galaxy System, Noah Medical). Patients with moderate-risk peripheral pulmonary nodules were enrolled in the study. Robotic bronchoscopy was performed using electromagnetic navigation with TiLT-assisted lesion guidance. Non-specific results were followed up until either a clear diagnosis was achieved or repeat radiology at 6 months demonstrated stability.

RESULTS

Eighteen patients (19 nodules) were enrolled. The average lesion size was 20 mm, and the average distance from the pleura was 11.6 mm. The target was successfully reached in 100% of nodules, and the biopsy tool was visualized inside the target lesion in all cases. A confirmed specific diagnosis was achieved in 17 nodules, 13 of which were malignant. In one patient, radiological monitoring confirmed a true non-malignant result. This translates to a yield of 89.5% (strict) to 94.7% (intermediate). Complications included one pneumothorax requiring observation only and another requiring an overnight chest drain. There was one case of severe pneumonia following the procedure.

CONCLUSION

In this first-in-human study, second-generation robotic bronchoscopy using electromagnetic navigation combined with integrated digital tomosynthesis was feasible with an acceptable safety profile and demonstrated a high diagnostic yield for small peripheral lung nodules.

High Tidal Volume, High Positive End Expiratory Pressure and Apneic Breath Hold Strategies (Lung Navigation Ventilation Protocol) With Cone Beam Computed Tomography Bronchoscopic Biopsy of Peripheral Lung Lesions: Results in 100 Patients

BACKGROUND

A dedicated anesthesia protocol for bronchoscopic lung biopsy-lung navigation ventilation protocol (LNVP)-specifically designed to mitigate atelectasis and reduce unnecessary respiratory motion, has been recently described. LNVP demonstrated significantly reduced dependent ground glass, sublobar/lobar atelectasis, and atelectasis obscuring target lesions compared with conventional ventilation.

METHODS

In this retrospective, single-center study, we examine the impact of LNVP on 100 consecutive patients during peripheral lung lesion biopsy. We report the incidence of atelectasis using cone beam computed tomography imaging, observed ventilatory findings, anesthesia medications, and outcomes, including diagnostic yield, radiation exposure, and complications.

RESULTS

Atelectasis was observed in a minority of subjects: ground glass opacity atelectasis was seen in 30 patients by reader 1 (28%) and in 18 patients by reader 2 (17%), with good agreement between readers (κ = 0.78). Sublobar/lobar atelectasis was observed in 23 patients by reader 1 and 26 patients by reader 2, also demonstrating good agreement (κ = 0.67). Atelectasis obscured target lesions in very few cases: 0 patients (0%, reader 1) and 3 patients (3%, reader 2). Diagnostic yield was 85.9% based on the AQuIRE definition. Pathology demonstrated 57 of 106 lesions (54%) were malignant, 34 lesions (32%) were benign, and 15 lesions (14%) were nondiagnostic.

CONCLUSION

Cone beam computed tomography images confirmed low rates of atelectasis, high tool-in-lesion confirmation rate, and high diagnostic yield. LNVP has a similar safety profile to conventional bronchoscopy. Most patients will require intravenous fluid and vasopressor support. Further study of LNVP and other ventilation protocols are necessary to understand the impact of ventilation protocols on bronchoscopic peripheral lung biopsy.

Mobile cone-beam computed tomography complementing shape-sensing robotic-assisted bronchoscopy in the small pulmonary nodule sampling: A multicentre experience

BACKGROUND AND OBJECTIVE

Shape-sensing robotic-assisted bronchoscopy (ssRAB) has expanded as an important diagnostic tool for peripheral pulmonary nodules (PPNs), with diagnostic yields ranging from 60% to 88%. However, sampling and diagnosing PPN less than 2 cm in size has historically been challenging. Mobile cone-beam computed tomography (mCBCT) has been recently integrated into ssRAB to improve diagnostic accuracy, but its added value remains uncertain. We aim to describe the role of mCBCT and determine if it provides any diagnostic advantage.

METHODS

A multicentre, retrospective study on the use of ssRAB and mCBCT in two tertiary care institutions: Mayo Clinic Florida and Massachusetts General Hospital. The primary outcome was diagnostic yield and sensitivity for malignancy of ssRAB complemented with mCBCT, compared to ssRAB with the standard 2D fluoroscopy.

RESULTS

A total of 192 nodules were biopsied from 173 patients. mCBCT was used in 117 (60.9%) nodules. The overall diagnostic yield was 85.4%. Diagnostic yield between subgroups with and without mCBCT was 83.8% and 88% (p = 0.417), respectively. The mCBCT group had fewer solid nodules (65.8% vs. 81.3%, p = 0.020) and a higher number of ground-glass nodules (10.3% vs. 1.3%, p = 0.016).

CONCLUSION

Overall, diagnostic yield between subgroups with and without mCBCT was similar. The complementary use of mCBCT to ssRAB allows proceduralists to target more complex and subsolid PPNs with a diagnostic yield comparable to simple solid PPNs while maintaining an excellent safety profile.

Cone-beam CT-based Navigation With Augmented Fluoroscopy of the Airways for Image-guided Bronchoscopic Biopsy of Peripheral Pulmonary Nodules: A Prospective Clinical Study

BACKGROUND

Cone-beam computed tomography (CBCT) and augmented fluoroscopy (AF), in which intraprocedural CBCT data is fused with fluoroscopy, have been utilized as a novel image-guidance technique for biopsy of peripheral pulmonary lesions. The aim of this clinical study is to determine the safety and diagnostic performance of CBCT-guided bronchoscopy with advanced software tools for procedural planning and navigational guidance with AF of the airways for biopsy of peripheral pulmonary nodules.

METHODS

Fifty-two consecutive subjects were prospectively enrolled in the AIRWAZE study (December 2018 to October 2019). Image-guided bronchoscopic biopsy procedures were performed under general anesthesia with specific ventilation protocols in a hybrid operating room equipped with a ceiling-mounted C-arm system. Procedural planning and image-guided bronchoscopy with CBCT and AF were performed using the Airwaze investigational device.

RESULTS

A total of 58 pulmonary lesions with a median size of 19.0 mm (range 7 to 48 mm) were biopsied. The overall diagnostic yield at index procedure was 87.9% (95% CI: 77.1%-94.0%). No severe adverse events related to CBCT-guided bronchoscopy, such as pneumothorax, bleeding, or respiratory failure, were observed.

CONCLUSION

CBCT-guided bronchoscopic biopsy with augmented fluoroscopic views of the airways and target lesion for navigational guidance is technically feasible and safe. Three-dimensional image-guided navigation biopsy is associated with high navigational success and a high diagnostic yield for peripheral pulmonary nodules.

Chinese expert consensus on cone-beam CT-guided diagnosis, localization and treatment for pulmonary nodules

Cone-beam computed tomography (CBCT) system can provide real-time 3D images and fluoroscopy images of the region of interest during the operation. Some systems can even offer augmented fluoroscopy and puncture guidance. The use of CBCT for interventional pulmonary procedures has grown significantly in recent years, and numerous clinical studies have confirmed the technology's efficacy and safety in the diagnosis, localization, and treatment of pulmonary nodules. In order to optimize and standardize the technical specifications of CBCT and guide its application in clinical practice, the consensus statement has been organized and written in a collaborative effort by the Professional Committee on Interventional Pulmonology of China Association for Promotion of Health Science and Technology.

Deformable 3D/3D CT-to-digital-tomosynthesis image registration in image-guided bronchoscopy interventions

Traditional navigational bronchoscopy procedures rely on preprocedural computed tomography (CT) and intraoperative chest radiography and cone-beam CT (CBCT) to biopsy peripheral lung lesions. This navigational approach is challenging due to the projective nature of radiography, and the high radiation dose, long imaging time, and large footprints of CBCT. Digital tomosynthesis (DTS) is considered an attractive alternative combining the advantages of radiography and CBCT. Only the depth resolution cannot match a full CBCT image due to the limited angle acquisition. To address this issue, preoperative CT is a good auxiliary in guiding bronchoscopy interventions. Nevertheless, CT-to-body divergence caused by anatomic changes and respiratory motion, hinders the effective use of CT imaging. To mitigate CT-to-body divergence, we propose a novel deformable 3D/3D CT-to-DTS registration algorithm employing a multistage, multiresolution approach and using affine and elastic B-spline transformation models with bone and lung mask images. A multiresolution strategy with a Gaussian image pyramid and a multigrid strategy within the B-spline model are applied. The normalized correlation coefficient is included in the cost function for the affine model and a multimetric weighted cost function is used for the B-spline model, with weights determined heuristically. Tested on simulated and real patient bronchoscopy data, the algorithm yields promising results. Assessed qualitatively by visual inspection and quantitatively by computing the Dice coefficient (DC) and the average symmetric surface distance (ASSD), the algorithm achieves mean DC of 0.82±0.05 and 0.74±0.05, and mean ASSD of 0.65±0.29mm and 0.93±0.43mm for simulated and real data, respectively. This algorithm lays the groundwork for CT-aided intraoperative DTS imaging in image-guided bronchoscopy interventions with future studies focusing on automated metric weight setting.

Robotic-Assisted Bronchoscopy: A Comprehensive Review of System Functions and Analysis of Outcome Data

The past two decades have witnessed a revolutionary era for peripheral bronchoscopy. Though the initial description of radial endobronchial ultrasound can be traced back to 1992, it was not until the mid-2000s that its utilization became commonplace, primarily due to the introduction of electromagnetic navigation (EMN) bronchoscopy. While the diagnostic yield of EMN-assisted sampling has shown substantial improvement over historical fluoroscopy-assisted bronchoscopic biopsy, its diagnostic yield plateaued at around 70%. Factors contributing to this relatively low diagnostic yield include discrepancies in computed tomography to body divergence, which led to unsuccessful lesion localization and resultant unsuccessful sampling of the lesion. Furthermore, much of peripheral bronchoscopy utilized a plastic extended working channel whose tips were difficult to finely aim at potential targets. However, the recent introduction of robotic-assisted bronchoscopy, and its associated stability within the peripheral lung, has ignited optimism for its potential to significantly enhance the diagnostic performance for peripheral lesions. Moreover, some envision this technology eventually playing a pivotal role in the therapeutic delivery to lung tumors. This review aims to describe the currently available robotic-assisted bronchoscopy technologies and to discuss the existing scientific evidence supporting these.

Balloon Dilatation for Bronchoscope Delivery in a Swine Model: A Novel Technique for Ultra-Peripheral Lung Field Access and Accurate Biopsy

INTRODUCTION

In transbronchial biopsy of peripheral pulmonary lesions, the bronchoscope can reach only a limited depth due to the progressive narrowing of bronchi, which may reduce the diagnostic rate. This study examined the balloon dilatation for bronchoscope delivery (BDBD) technique, employing a novel balloon device to enhance bronchoscopy into the peripheral lung areas.

METHODS

Anaesthetised swine served as our primary model. Using computed tomography (CT) scans, we positioned virtual targets characterised by a positive bronchus sign and a diameter of 20 mm beneath the pleura. The bronchoscope was navigated along the pathways determined from the CT images. We performed balloon dilatation when bronchial narrowing obstructed progress to assess whether balloon dilatation would enable the bronchoscope to enter further into the periphery.

RESULTS

We established 21 virtual targets on the CT scans. An average of 12.1 branches were identified along the pathways on the CT scans; however, bronchoscopy without BDBD only allowed access to an average of 6.7 branches. Based on 72 balloon dilatations with 3.0-mm or 4.0-mm ultra-thin bronchoscopes, there was an average increased access of 3.43 and 5.14 branches per route, respectively, with no significant BDBD complications. The bronchoscope was able to reach the planned location along all pathways, and the mean final bronchoscopic endpoints were at an average distance of 14.7 mm from the pleura. Post-procedure CT confirmed biopsy accuracy.

CONCLUSION

The BDBD technique can enhance access of a flexible bronchoscope into the peripheral lung fields, which could potentially allow more accurate transbronchial interventions for peripheral targets.

Imaging in peripheral bronchoscopy

PURPOSE OF REVIEW

Historically the sampling of peripheral lung lesions via bronchoscopy has suffered from inferior diagnostic outcomes relative to transthoracic needle aspiration, and neither a successful bronchoscopic navigation nor a promising radial ultrasonographic image of one's target lesion guarantees a successful biopsy. Fortunately, many of peripheral bronchoscopy's shortcomings - including an inability to detect and compensate for computed tomography (CT)-body divergence, and the absence of tool-in-lesion confirmation - are potentially remediable through the use of improved intraprocedural imaging techniques.

RECENT FINDINGS

Recent advances in intraprocedural imaging, including the integration of cone beam CT, digital tomosynthesis, and augmented fluoroscopy into bronchoscopic procedures have yielded promising results. These advanced imaging modalities may improve the outcomes of peripheral bronchoscopy through the detection and correction of navigational errors, CT-body divergence, and malpositioned biopsy instruments.

SUMMARY

The incorporation of advanced imaging is an essential step in the improvement of peripheral bronchoscopic procedures.

"Tool-in-lesion" Accuracy of Galaxy System-A Robotic Electromagnetic Navigation BroncHoscopy With Integrated Tool-in-lesion-Tomosynthesis Technology: The MATCH Study

BACKGROUND

The Galaxy System (Noah Medical) is a novel robotic endoluminal platform using electromagnetic navigation combined with integrated tomosynthesis technology and augmented fluoroscopy. It provides intraprocedural imaging to correct computerized tomography (CT) to body divergence and novel confirmation of tool-in-lesion (TIL). The primary aim of this study was to assess the TIL accuracy of the robotic bronchoscope with integrated digital tomosynthesis and augmented fluoroscopy.

METHODS

Four operators conducted the experiment using 4 pigs. Each physician performed between 4 and 6 nodule biopsies for 20 simulated lung nodules with purple dye and a radio pacifier. Using Galaxy's "Tool-in-Lesion Tomography (TOMO+)" with augmented fluoroscopy, the physician navigated to the lung nodules, and a tool (needle) was placed into the lesion. TIL was defined by the needle in the lesion determined by cone-beam CT.

RESULTS

The lung nodule's average size was 16.3 ± 0.97 mm and was predominantly in the lower lobes (65%). All 4 operators successfully navigated to all (100%) of the lesions in an average of 3 minutes and 39 seconds. The median number of tomosynthesis sweeps was 3 and augmented fluoroscopy was utilized in most cases (17/20 or 85%). TIL after the final TOMO sweep was 95% (19/20) and tool-touch-lesion was 5% (1/20). Biopsy yielding purple pigmentation was also 100% (20/20).

CONCLUSION

The Galaxy System demonstrated successful digital TOMO confirmed TIL success in 95% (19/20) of lesions and tool-touch-lesion in 5% (1/20) as confirmed by cone-beam CT. Successful diagnostic yield was achieved in 100% (20/20) of lesions as confirmed by intralesional pigment acquisition.

Advances in navigating to the nodule and targeting

PURPOSE OF REVIEW

The multitude of available platforms and imaging modalities for navigational bronchoscopy, in combination with the various sampling tools that can be used intra-procedurally, is complex. This review seeks to describe the recent developments in peripheral bronchoscopy in regards to navigation, imaging, and sampling target lesions in the pulmonary parenchyma.

RECENT FINDINGS

Robotic assisted bronchoscopy has improved navigation to the peripheral airways for sampling of peripheral parenchymal lesions. These navigational platforms use innovative technology utilizing electromagnetic navigation and shape-sensing technology for guidance. The greatest improvement has been the stabilization of the robotic scope in the periphery to allow for accurate sampling. Despite improvements in these platforms, limitations of CT to body divergence continue to impact navigation to the lesion and therefore diagnostic yield of the procedure. Advanced intraprocedural imaging with cone beam CT or augmented fluoroscopy has been a recent focus to improve this area. Further, the adoption of newer sampling tools, such as cryobiopsy, offers the possibility of increased diagnostic yield.

SUMMARY

The developments in advanced bronchoscopy will impact the role of biopsy in the diagnosis of peripheral pulmonary parenchymal lesions.

Treatment strategies for malignant pulmonary nodule: beyond lobectomy. Point-counterpoint

PURPOSE OF REVIEW

Technological advancement in low-dose computed tomography resulted in an increased incidental discovery of early-stage lung cancer and multifocal ground glass opacity. The demand for parenchyma-preserving treatment strategies is greater now than ever. Pulmonary ablative therapy is a groundbreaking technique to offer local ablative treatment in a lung-sparing manner. It has become a promising technique in lung cancer management with its diverse applicability. In this article, we will review the current development of ablative therapy in lung and look into the future of this innovative technique.

RECENT FINDINGS

Current literature suggests that ablative therapy offers comparable local disease control to other local therapies and stereotactic body radiation therapy (SBRT), with a low risk of complications. In particular, bronchoscopic microwave ablation (BMWA) has considerably fewer pleural-based complications due to the avoidance of pleural puncture. BMWA can be considered in the multidisciplinary treatment pathway as it allows re-ablation and allows SBRT after BMWA.

SUMMARY

With the benefits which ablative therapy offers and its ability to incorporate into the multidisciplinary management pathway, we foresee ablative therapy, especially BMWA gaining significance in lung cancer treatment. Future directions on developing novel automated navigation platforms and the latest form of ablative energy would further enhance clinical outcomes for our patients.

Landmark Based Bronchoscope Localization for Needle Insertion Under Respiratory Deformation

Bronchoscopy is currently the least invasive method for definitively diagnosing lung cancer, which kills more people in the United States than any other form of cancer. Successfully diagnosing suspicious lung nodules requires accurate localization of the bronchoscope relative to a planned biopsy site in the airways. This task is challenging because the lung deforms intraoperatively due to respiratory motion, the airways lack photometric features, and the anatomy's appearance is repetitive. In this paper, we introduce a real-time camera-based method for accurately localizing a bronchoscope with respect to a planned needle insertion pose. Our approach uses deep learning and accounts for deformations and overcomes limitations of global pose estimation by estimating pose relative to anatomical landmarks. Specifically, our learned model considers airway bifurcations along the airway wall as landmarks because they are distinct geometric features that do not vary significantly with respiratory motion. We evaluate our method in a simulated dataset of lungs undergoing respiratory motion. The results show that our method generalizes across patients and localizes the bronchoscope with accuracy sufficient to access the smallest clinically-relevant nodules across all levels of respiratory deformation, even in challenging distal airways. Our method could enable physicians to perform more accurate biopsies and serve as a key building block toward accurate autonomous robotic bronchoscopy.

Radiation dose of cone beam CT combined with shape sensing robotic assisted bronchoscopy for the evaluation of pulmonary lesions: an observational single center study

Background

Shape sensing robotic-assisted bronchoscopy (ssRAB) combined with radial endobronchial ultrasound (r-EBUS) and cone beam computed tomography (CBCT) is a newer diagnostic modality for the evaluation of pulmonary lesions. There is limited data describing the radiation dose of CBCT combined with ssRAB. The purpose of this study was to describe the technical factors associated with the use of CBCT combined with ssRAB to biopsy pulmonary lesions.

Methods

We conducted a single center, prospective observational study of patients undergoing ssRAB combined with fixed CBCT for the pulmonary lesion biopsy. We report our patient demographics, and pulmonary lesion and procedure characteristics.

Results

A total of 241 ssRAB procedures were performed to biopsy 269 pulmonary lesions. The mean lesion size was measured in the following dimensions: anteroposterior (18.0±8.8 mm), transverse (17.2±10.5 mm), and craniocaudal (17.7±10.2 mm). A mean of 1.5±0.7 (median: 1, range: 1-4) CBCT spins were performed. The mean total fluoroscopy time (FT) was 5.6±2.9 minutes. The mean radiation dose of cumulative air kerma (CAK) was 63.5±46.7 mGy and the mean cumulative dose area product (DAP) was 22.6±16.0 Gy·cm2. Diagnostic yield calculated based on results at index bronchoscopy was 85.9%. There was a low rate of complications with 8 pneumothoraces (3.3%), 5 (2.1%) of which required chest tube placement.

Conclusions

We describe the use of ssRAB combined with CBCT to biopsy pulmonary lesions as a safe diagnostic modality with relatively low radiation dose that is potentially comparable to other image guided sampling modalities. Bronchoscopists should be cognizant of the radiation use during the procedure for both patient and staff safety.

Real-World Impact of Robotic-Assisted Bronchoscopy on the Staging and Diagnosis of Lung Cancer: The Shape of Current and Potential Opportunities

The approach to peripheral pulmonary lesions (PPL) has been evolving continuously. Advanced bronchoscopic navigational techniques have improved the airway-based approaches to these lesions. Robotic Assisted Bronchoscopy (RAB) can be considered the current pinnacle of this evolution; allowing for a safer approach to sampling lesions previously considered outside of bronchoscopic reach. We present a comprehensive review of the changing epidemiology of lung cancer and the importance of early tissue sampling, the evolution of sampling and navigational bronchoscopic techniques, technical considerations and evidence pertaining to the use of RAB, and adjunct techniques in the diagnosis of lung cancer. Complications and future applications of RAB are also discussed.

Robotic bronchoscopy in diagnosing lung cancer-the evidence, tips and tricks: a clinical practice review

The development of robotic-assisted bronchoscopy has empowered bronchoscopists to access the periphery of the lung with more confidence and promising accuracy. This is due in large to the superior maneuverability, further reach, and stability of these technologies. Despite the advantages of robotic bronchoscopy, there are some drawbacks to using these technologies, such as the loss of tactile feedback, the need to overcome computed tomography (CT)-to-body divergence, and the potential for overreliance on the navigation software. There are currently two robotic bronchoscopy platforms on the US market, the MonarchTM Platform by Auris Health© (Redwood City, CA, USA) and the IonTM endoluminal robotic bronchoscopy platform by Intuitive Surgical© (Sunnyvale, CA, USA). In this clinical practice review, we highlight the evidence and strategies for successful clinical use of both robotic bronchoscopy platforms for pulmonary lesion sampling. Specifically, we will review pre-procedural considerations, such as procedural mapping, room set-up and anesthesia considerations. We will also review the technical aspects of using the robotic bronchoscopy platforms, such as how to compensate for the loss of tactile feedback, optimize visualization, use of ancillary technology to accommodate for CT-to-body divergence, employ best practices for sampling techniques, and utilize information from rapid on-site evaluation (ROSE) to aid in improving diagnostic yield.

Cone-beam CT in lung biopsy: a clinical practice review on lessons learned and future perspectives

Pulmonary nodules with intermediate to high risk of malignancy should preferably be diagnosed with image guide minimally invasive diagnostics before treatment. Several technological innovations have been developed to endobronchially navigate to these lesions and obtain tissue for diagnosis. This review addresses these technological advancements in navigation bronchoscopy in three basic steps: navigation, position confirmation and acquisition, with a specific focus on cone-beam computed tomography (CBCT). For navigation purposes ultrathin bronchoscopy combined with virtual bronchoscopy navigation, electromagnetic navigation and robotic assisted bronchoscopy all achieve good results as a navigation guidance tool, but cannot confirm location or guide biopsy positioning. Diagnostic yield has seen improvement by combining these techniques with a secondary imaging tool like radial endobronchial ultrasound (rEBUS) and fluoroscopy. For confirmation of lesion access, rEBUS provides local detailed ultrasound-imaging and can be used to confirm lesion access in combination with fluoroscopy, measure nodule-contact area length and determine catheter position for sampling. CBCT is the only technology that can provide precise 3D positioning confirmation. When focusing on tissue acquisition, there is often more than 10% difference between reaching the target and getting a diagnosis. This discrepancy is multifactorial and caused by breathing movements, small samples sizes, instrument tip displacements by tool rigidity and tumour inhomogeneity. Yield can be improved by targeting fluorodeoxyglucose (FDG)-avid regions, immediate feedback of rapid onsite evaluation, choosing sampling tools with different passive stiffnesses, by increasing the number biopsies taken and (future) catheter modifications like (robotic assisted-) active steering. CBCT with augmented fluoroscopy (CBCT-AF) based navigation bronchoscopy combines navigation guidance with 3D-image confirmation of instrument-in-lesion positioning in one device. CBCT-AF allows for overlaying the lesion and navigation pathway and the possibility to outline trans-parenchymal pathways. It can help guide and verify sampling in 3D in near real-time. Disadvantages are the learning curve, the inherent use of radiation and limited availability/access to hybrid theatres. A mobile C-arm can provide 3D imaging, but lower image quality due to lower power and lower contrast-to-noise ratio is a limiting factor. In conclusion, a multi-modality approach in experienced hands seems the best option for achieving a diagnostic accuracy >85%. Either adequate case selection or detailed 3D imaging are essential to obtain high accuracy. For current and future transbronchial treatments, high-resolution (CBCT) 3D-imaging is essential.

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.

Diagnostic accuracy and safety of electromagnetic navigation transthoracic needle biopsy under moderate sedation for the diagnosis of peripheral pulmonary lesions

Background

Novel approaches using virtual computed tomography (CT) guidance, namely electromagnetic navigation transthoracic needle biopsy (EMN-TTNB), enable physicians to perform percutaneous lung biopsies. However, there are very few studies on the clinical experiences of EMN-TTNB, and in previous studies, the procedure was usually performed under deep sedation. This study aimed to determine the diagnostic accuracy and safety of EMN-TTNB under moderate sedation.

Methods

We conducted a retrospective analysis of patients who underwent EMN-TTNB under moderate sedation between May 2021 and November 2022 at Hallym University Dongtan Sacred Heart Hospital in South Korea. Moderate sedation was achieved with midazolam injection in the bronchoscopy room using the Veran SPiNperc EM guidance system (Veran Medical, St Louis, MO, USA). Clinical data were collected by review of medical records, and diagnostic accuracy and safety were calculated.

Results

Thirty-two patients were enrolled (mean age 70.8±11.1 years); 56.3% were male. The mean size of the pulmonary lesions was 36.9±17.4 mm, and the median (interquartile range) distance from the pleura was 15.5 (0.0-30.0) mm. The diagnostic accuracy of EMN-TTNB was 75.0% (21/28), excluding four indeterminate cases. Fourteen patients (50.0%, 14/28) had true-positive and seven patients (25.0%, 7/28) had true-negative lesions. There were no severe adverse reactions such as pneumothorax, respiratory failure, or death, except one case of hemoptysis.

Conclusions

EMN-TTNB under moderate sedation showed an acceptable diagnostic accuracy and good safety profile. The new technology allows physicians to perform percutaneous lung biopsies without the intervention of a radiologist or anesthesiologist.

Prognostic predictors of radical resection of stage I-IIIB non-small cell lung cancer: the role of preoperative CT texture features, conventional imaging features, and clinical features in a retrospectively analyzed

BACKGROUND

To investigate the value of preoperative computed tomography (CT) texture features, routine imaging features, and clinical features in the prognosis of non-small cell lung cancer (NSCLC) after radical resection.

METHODS

Demographic parameters and clinically features were analyzed in 107 patients with stage I-IIIB NSCLC, while 73 of these patients received CT scanning and radiomic characteristics for prognosis assessment. Texture analysis features include histogram, gray size area matrix and gray co-occurrence matrix features. The clinical risk features were identified using univariate and multivariate logistic analyses. By incorporating the radiomics score (Rad-score) and clinical risk features with multivariate cox regression, a combined nomogram was built. The nomogram performance was assessed by its calibration, clinical usefulness and Harrell's concordance index (C-index). The 5-year OS between the dichotomized subgroups was compared using Kaplan-Meier (KM) analysis and the log-rank test.

RESULTS

Consisting of 4 selected features, the radiomics signature showed a favorable discriminative performance for prognosis, with an AUC of 0.91 (95% CI: 0.84 ~ 0.97). The nomogram, consisting of the radiomics signature, N stage, and tumor size, showed good calibration. The nomogram also exhibited prognostic ability with a C-index of 0.91 (95% CI, 0.86-0.95) for OS. The decision curve analysis indicated that the nomogram was clinically useful. According to the KM survival curves, the low-risk group had higher 5-year survival rate compared to high-risk.

CONCLUSION

The as developed nomogram, combining with preoperative radiomics evidence, N stage, and tumor size, has potential to preoperatively predict the prognosis of NSCLC with a high accuracy and could assist to treatment for the NSCLC patients in the clinic.

O-arm CT for Confirmation of Successful Navigation During Robotic Assisted Bronchoscopy

BACKGROUND

Robotic assisted bronchoscopy (RAB) is designed to increase bronchoscopic accessibility for difficult to reach pulmonary lesions. One limitation to success of RAB is computed tomography (CT) to body divergence. Real time imaging with cone beam CT is increasingly utilized for confirmation of correct navigation and tool-in-lesion during RAB. O-arm CT is a 3-dimensional imaging modality, which has not previously been described for use with RAB. Our purpose is to display the feasibility, ease of use, and high rate of confirmation of tool-in-lesion when using O-arm CT during RAB.

METHODS

Single center, retrospective review of 75 patients undergoing RAB with intraprocedural use of O-arm CT.

RESULTS

Median patient age was 65 years. Forty-nine percent of cases involved nodules ≤2 cm. Bronchus sign was absent in 44% of cases. Median procedure time was 80 minutes. Median number of O-arm CT runs per case was 2. The median effective dose of radiation was 7.2 millisieverts. Tool-in-lesion was confirmed in 97% (77 of 79) of cases. Definitive diagnosis was reached in 61 to 68 of 79 cases (77% to 86%). There were 2 cases of pneumothorax (2.5%), one of which needed intervention with tube thoracostomy.

CONCLUSIONS

O-arm CT is an effective, and convenient alternative to other 3-dimensional imaging modalities for intraprocedural confirmation of tool-in-lesion during RAB.

Robotic bronchoscopy: potential in diagnosing and treating lung cancer

INTRODUCTION

Lung cancer remains the deadliest form of cancer in the world. Screening through low-dose CT scans has shown improved detection of pulmonary nodules; however, with the introduction of robotic bronchoscopy, accessing and biopsying peripheral pulmonary nodules from the airway has expanded. Improved diagnostic yield through enhanced navigation has made robotic bronchoscopy an ideal diagnostic technology for many proceduralists. Studies have demonstrated that robotic bronchoscopes can reach further with improved maneuverability into the distal airways compared to conventional bronchoscopes.

AREAS COVERED

This review paper highlights the literature on the technological advancements associated with robotic bronchoscopy and the future directions the field of interventional pulmonary may utilize this modality for in the treatment of lung cancer. Referenced articles were included at the discretion of the authors after a database search of the particular technology discussed.

EXPERT OPINION

As the localization of target lesions continues to improve, robotic platforms that provide reach, stability, and accuracy paves the way for future research in endoluminal treatment for lung cancer. Future studies with intratumoral injection of chemotherapy and immunotherapy and ablation modalities are likely to come in the coming years.

The Use of Robotic-Assisted Bronchoscopy in the Diagnostic Evaluation of Peripheral Pulmonary Lesions: A Paradigm Shift

Despite recent developments, evaluation of peripheral pulmonary lesions (PPL) remains clinically challenging, and the diagnostic yield of many image-guided and bronchoscopy methods is still poor. Furthermore, complications from such procedures, such as pneumothorax and airway hemorrhage, are a major concern. Recently launched robotic-assisted bronchoscopy (RAB) platforms are still in the early exploration stage and may provide another tool for achieving PPL evaluation. We present our experience here as a retrospective cohort study describing the 12-month diagnostic yield with the shape-sensing Ion™ platform for minimally invasive peripheral lung biopsy. The study describes forty-two patients undergoing shape sensing robotic-assisted bronchoscopy (ssRAB) at our institute. The early performance trend reveals a lesion localization of 100% and an overall 12-month diagnostic yield of 88.10%. The diagnostic yield for lesions less than 20 mm was 76% and for lesions greater than 20 mm was 100%. We also report our complication profile; we noted no pneumothoraces, excessive bleeding, or post-operative complications. In comparison to traditional bronchoscopy and image-guided modalities, our experience shows that ssRAB can be utilized successfully to travel to extremely small peripheral lesions with a higher diagnostic yield and better safety profile.

Advanced Imaging for Robotic Bronchoscopy: A Review

Recent advances in navigational platforms have led bronchoscopists to make major strides in diagnostic interventions for pulmonary parenchymal lesions. Over the last decade, multiple platforms including electromagnetic navigation and robotic bronchoscopy have allowed bronchoscopists to safely navigate farther into the lung parenchyma with increased stability and accuracy. Limitations persist, even with these newer technologies, in achieving a similar or higher diagnostic yield when compared to the transthoracic computed tomography (CT) guided needle approach. One of the major limitations to this effect is due to CT-to-body divergence. Real-time feedback that better defines the tool-lesion relationship is vital and can be obtained with additional imaging using radial endobronchial ultrasound, C-arm based tomosynthesis, cone-beam CT (fixed or mobile), and O-arm CT. Herein, we describe the role of this adjunct imaging with robotic bronchoscopy for diagnostic purposes, describe potential strategies to counteract the CT-to-body divergence phenomenon, and address the potential role of advanced imaging for lung tumor ablation.

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.

Robotic Bronchoscopy: Review of Three Systems

Robotic bronchoscopy (RB) has been shown to improve access to smaller and more peripheral lung lesions, while simultaneously staging the mediastinum. Pre-clinical studies demonstrated extremely high diagnostic yields, but real-world RB yields have yet to fully matched up in prospective studies. Despite this, RB technology has rapidly evolved and has great potential for lung-cancer diagnosis and even treatment. In this article, we review the historical and present challenges with RB in order to compare three RB systems.

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.

Enhancing Nodule Biopsy Through Technology Integration

Technology in navigating to peripheral pulmonary nodules has improved in recent years. The recent integration of a robotic platform using shape-sensing technology and mobile cone-beam computed tomography imaging technology has enhanced confidence in sampling lesions with intraprocedural imaging by complimenting the pre-planned navigation to peripheral pulmonary nodules. We present 2 cases using the software integration that improved the robotic catheter positioning to allow for diagnostic specimens to be obtained in the initial biopsies.

3D-2D image registration in the presence of soft-tissue deformation in image-guided transbronchial interventions

Purpose. Target localization in pulmonary interventions (e.g. transbronchial biopsy of a lung nodule) is challenged by deformable motion and may benefit from fluoroscopic overlay of the target to provide accurate guidance. We present and evaluate a 3D-2D image registration method for fluoroscopic overlay in the presence of tissue deformation using a multi-resolution/multi-scale (MRMS) framework with an objective function that drives registration primarily by soft-tissue image gradients.Methods. The MRMS method registers 3D cone-beam CT to 2D fluoroscopy without gating of respiratory phase by coarse-to-fine resampling and global-to-local rescaling about target regions-of-interest. A variation of the gradient orientation (GO) similarity metric (denotedGO') was developed to downweight bone gradients and drive registration via soft-tissue gradients. Performance was evaluated in terms of projection distance error at isocenter (PDE_iso). Phantom studies determined nominal algorithm parameters and capture range. Preclinical studies used a freshly deceased, ventilated porcine specimen to evaluate performance in the presence of real tissue deformation and a broad range of 3D-2D image mismatch.Results. Nominal algorithm parameters were identified that provided robust performance over a broad range of motion (0-20 mm), including an adaptive parameter selection technique to accommodate unknown mismatch in respiratory phase. TheGO'metric yielded median PDE_iso= 1.2 mm, compared to 6.2 mm for conventionalGO.Preclinical studies with real lung deformation demonstrated median PDE_iso= 1.3 mm with MRMS +GO'registration, compared to 2.2 mm with a conventional transform. Runtime was 26 s and can be reduced to 2.5 s given a prior registration within ∼5 mm as initialization.Conclusions. MRMS registration via soft-tissue gradients achieved accurate fluoroscopic overlay in the presence of deformable lung motion. By driving registration via soft-tissue image gradients, the method avoided false local minima presented by bones and was robust to a wide range of motion magnitude.

Transbronchial real-time lung tumor localization with folate receptor-targeted near-infrared molecular imaging: A proof of concept study in animal models

OBJECTIVE

The diagnostic yield of bronchoscopy is not satisfactory, even with recent navigation technologies, especially for tumors located outside of the bronchial lumen. Our objective was to perform a preclinical assessment of folate receptor-targeted near-infrared imaging-guided bronchoscopy to detect peribronchial tumors.

METHODS

Pafolacianine, a folate receptor-targeted molecular imaging agent, was used as a near-infrared fluorescent imaging agent. An ultra-thin composite optical fiberscope was used for laser irradiation and fluorescence imaging. Subcutaneous xenografts of KB cells in mice were used as folate receptor-positive tumors. Tumor-to-background ratio was calculated by the fluorescence intensity value of muscle tissues acquired by the ultra-thin composite optical fiberscope system and validated using a separate spectral imaging system. Ex vivo swine lungs into which pafolacianine-laden KB tumors were transplanted at various sites were used as a peribronchial tumor model.

RESULTS

With the in vivo murine model, tumor-to-background ratio observed by ultra-thin composite optical fiberscope peaked at 24 hours after pafolacianine injection (tumor-to-background ratio: 2.56 at 0.05 mg/kg, 2.03 at 0.025 mg/kg). The fluorescence intensity ratios between KB tumors and normal mouse lung parenchyma postmortem were 6.09 at 0.05 mg/kg and 5.08 at 0.025 mg/kg. In the peribronchial tumor model, the ultra-thin composite optical fiberscope system could successfully detect fluorescence from pafolacianine-laden folate receptor-positive tumors with 0.05 mg/kg at the carina and those with 0.025 mg/kg and 0.05 mg/kg in the peripheral airway.

CONCLUSIONS

Transbronchial detection of pafolacianine-laden folate receptor-positive tumors by near-infrared imaging was feasible in ex vivo swine lungs. Further in vivo preclinical assessment is needed to confirm the feasibility of this technology.

Navigational Bronchoscopy with Cryobiopsy for Diagnosis of ILD

Background

Interstitial lung diseases (ILDs) are a group of parenchymal pulmonary diseases in which pathologic diagnosis is essential. Although cryobiopsy has a high diagnostic yield, the complication rate remains high. Case Presentation. We report two cases of lung cryobiopsy guided by navigational bronchoscopy (LCB) for the diagnosis of ILD. In both cases, a CT chest angiogram (CTA) using a navigational protocol was performed. Targets were premarked and reached with the navigational system. Radial ultrasound (RU) was applied in combination with fluoroscopy guidance (FG) prior to sampling. Both patients achieved a final diagnosis; they were discharged home after procedure and no complications were noted. Discussion. By using a CTA with navigational guidance, we were able to perform cryobiopsy in areas with most disease activity and least vascularization.

Conclusion

LCB used with navigational guidance for the diagnosis of ILD provides may be a safe and effective procedure that provides high diagnostic yield. Limitations include cost, availability, and expertise. Larger trials are needed to confirm the additional benefit.

Size and vision: Impact of fluoroscopic navigation, digital tomosynthesis, and continuous catheter tip tracking on diagnostic yield of small, bronchus sign negative lung nodules

INTRODUCTION

Accurate biopsies of lung nodules, including small (<2 cm), bronchus sign negative lesions, remain challenging. Technological advances, however, may improve outcomes. We describe our experience using a novel system combining fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking to guide lung nodule biopsies.

METHODS

Demographic data, procedural characteristics, and biopsy results from prospectively enrolled patients were collected.

RESULTS

159 nodules (144 patients) were biopsied. Average nodule size was 22.2 ± 15.2 mm (axial), 21.7 ± 13.9 mm (coronal), and 33.2 ± 20.5 mm (sagittal), with 45% (n = 72) <2 cm in all dimensions and 66% (n = 105) without a bronchus sign. Diagnostic yield was 84% (134/159), with malignancy (n = 75, 47%) most common. A diagnosis was obtained in 75% (n = 54/72) of lesions that were <2 cm in all dimensions and 79% (n = 83/105) of bronchus sign negative lesions. Unadjusted generalized mixed-effects logistic regression models showed that nodule size as a categorical variable (>2 cm in any dimension) and as a continuous variable in the coronal dimension, the presence of a bronchus sign, and a concentric radial EBUS view had an increased odds ratio for diagnosis. A concentric radial EBUS view also had an increased OR for diagnosis in a fully adjusted mixed-effects logistic regression model.

CONCLUSION

Fluoroscopic navigation with digital tomosynthesis and continuous catheter tip tracking shows an overall improved diagnostic accuracy compared to historical controls, including for small, bronchus sign negative lesions. Future studies clarifying the optimal modality for patients with different nodules will be of importance to provide the most appropriate procedure tailored to each individual lesion's unique characteristics.

A Novel Electromagnetic Navigation Bronchoscopy System for the Diagnosis of Peripheral Pulmonary Nodules: A Randomized Trial

RATIONALE

Endobronchial ultrasound (EBUS) combined with a guide sheath (GS) as an instrument for confirming the proximity of the bronchoscope and its relationship to the lesion can increase the diagnostic yield when conducting transbronchial lung biopsy of peripheral pulmonary nodules (PPNs). A novel electromagnetic navigational bronchoscopy (ENB) system comprising a thinner locatable sensor probe as a guidance instrument was developed to be suitable for a thin bronchoscope with a 2-mm-diameter working channel. The diagnostic efficacy of EBUS-GS with or without this ENB system has not been confirmed.

OBJECTIVES

To compare the diagnostic value and safety of EBUS-GS with or without ENB system for diagnosing PPNs.

METHODS

A prospective, multicenter, randomized controlled clinical trial was designed and conducted at 3 centers. Patients with PPNs suspected to be malignant were enrolled and randomly assigned to the ENB-EBUS-GS group or EBUS-GS group. The primary endpoint was the diagnostic yield in each group. The secondary endpoint was the procedural time and other factors affecting diagnostic yield. The safety endpoint was procedural complications.

RESULTS

Four hundred participants were enrolled from July 2018 to October 2019 and 385 patients were analyzed, with 193 in the ENB-EBUS-GS group and 192 in the EBUS-GS group. The mean nodule size was 21.7±5.3 mm. The diagnostic yields were 82.9% (95% confidence interval (CI), 77.6%-88.2%) in the ENB-EBUS-GS group and 73.4% (95% CI, 67.2%-79.7%) in the EBUS-GS group. The difference between the two groups was 9.5% (95% CI, 2.6%-16.3%), with an adjusted difference of 9.0% (95% CI, 2.3%-15.8%), after adjusting for the stratification factors and center. The time for finding lesions in the ENB-EBUS-GS was shorter than that in the EBUS-GS group (213.2±145.6s vs. 264.8±189.5s, p=0.003). And intraoperative hemorrhage occurred 3.6% in the ENB-EBUS-GS group and 3.1% in the EBUS-GS group, without significant differences between the two groups.

CONCLUSIONS

The novel ENB system combined with EBUS-GS demonstrated improved ability to locate PPNs, achieving a high diagnostic yield for PPNs compared to EBUS-GS alone in a safe and efficient procedure. Clinical trial registered with ClinicalTrials.gov (NCT03569306).

Combining Shape-Sensing Robotic Bronchoscopy With Mobile Three-Dimensional Imaging to Verify Tool-in-Lesion and Overcome Divergence: A Pilot Study

Objective

To determine whether CT-to-body divergence can be overcome to improve the diagnostic yield of peripheral pulmonary nodules with the combination of shape-sensing robotic-assisted bronchoscopy (SSRAB) and portable 3-dimensional (3D) imaging.

Patients and Methods

A single-center, prospective, pilot study was conducted from February 9, 2021, to August 4, 2021, to evaluate the combined use of SSRAB and portable 3D imaging to visualize tool-in-lesion as a correlate to diagnostic yield.

Results

Thirty lesions were subjected to biopsy in 17 men (56.7%) and 13 women (43.3%). The median lesion size was 17.5 mm (range, 10-30 mm), with the median airway generation of 7 and the median distance from pleura of 14.9 mm. Most lesions were in the upper lobes (18, 60.0%). Tool-in-lesion was visualized at the time of the procedure in 29 lesions (96.7%). On the basis of histopathologic review, 22 (73.3%) nodules were malignant and 6 (20.0%) were benign. Two (6.7%) specimens were suggestive of inflammation, and the patients elected observation. The mean number of spins was 2.5 (±1.6) with a mean fluoroscopy time of 8.7 min and a mean dose area product of 50.3 Gy cm² (±32.0 Gy cm²). There were no episodes of bleeding or pneumothorax. The diagnostic yield was 93.3%.

Conclusion

This pilot study shows that the combination of mobile 3D imaging and SSRAB of pulmonary nodules appears to be safe and feasible. In conjunction with appropriate anesthetic pathways, nodule motion and divergence can be overcome in most patients.

Trial Registration

https://clinicaltrials.gov Identifier NCT04740047

Contemporary Concise Review 2021: Pulmonary nodules from detection to intervention

The US Preventive Task Force (USPSTF) has updated screening criteria by expanding age range and reducing smoking history required for eligibility; the International Lung Screen Trial (ILST) data have shown that PLCOM2012 performs better for eligibility than USPSTF criteria. Screening adherence is low (4%-6% of potential eligible candidates in the United States) and depends upon multiple system and patient/candidate-related factors. Smoking cessation in lung cancer improves survival (past prospective trial data, updated meta-analysis data); smoking cessation is an essential component of lung cancer screening. Circulating biomarkers are emerging to optimize screening and early diagnosis. COVID-19 continues to affect lung cancer treatment and screening through delays and disruptions; specific operational challenges need to be met. Over 70% of suspected malignant lesions develop in the periphery of the lungs. Bronchoscopic navigational techniques have been steadily improving to allow greater accuracy with target lesion approximation and therefore diagnostic yield. Fibre-based imaging techniques provide real-time microscopic tumour visualization, with potential diagnostic benefits. With significant advances in peripheral lung cancer localization, bronchoscopically delivered ablative therapies are an emerging field in limited stage primary and oligometastatic disease. In advanced stage lung cancer, small-volume samples acquired through bronchoscopic techniques yield material of sufficient quantity and quality to support clinically relevant biomarker assessment.

Lung Navigation Ventilation Protocol to Optimize Biopsy of Peripheral Lung Lesions

BACKGROUND

Computed tomography-to-body divergence caused by respiratory motion, atelectasis, diaphragmatic motion and other factors is an obstacle to peripheral lung biopsies. We examined a conventional ventilation strategy versus a lung navigation ventilation protocol (LNVP) optimized for intraprocedural 3-dimensional image acquisition and bronchoscopic biopsy of peripheral lung nodules.

METHODS

A retrospective, single center study was conducted in consecutive subjects with peripheral lung lesions measuring <30 mm. Effects of ventilation strategies including atelectasis and tool-in-lesion confirmation were assessed using cone beam computed tomography images. Diagnostic yield was also evaluated. Complications were assessed through 7 days.

RESULTS

Fifty subjects were included (25 per group) with 27 nodules in the conventional group and 25 nodules in the LNVP group. Atelectasis was assessed by 2 blinded readers: [reader 1 (R1) and reader 2 (R2)]. Atelectasis was more prevalent in the conventional ventilation group, both for dependent atelectasis (R1: 64% and R2: 68% vs. R1: 36% and R2: 16%, P=0.00014) and sublobar/lobar atelectasis (R1: 48% and R2: 56% vs. R1: 20% and R2: 32%, P=0.01). Similarly, the target lesion was obscured due to atelectasis more often in the conventional ventilation group (R1: 36% and R2: 36% vs. R1: 4% and R2: 8%, P=0.01). Diagnostic yield was 70% for conventional ventilation and 92% for LNVP (P=0.08).

CONCLUSION

LNVP demonstrated markedly reduced dependent and sublobar/lobar atelectasis and lesions either partially or completely obscured by atelectasis compared with conventional ventilation. Future prospective studies are necessary to understand the impact of protocolized ventilation strategies for bronchoscopic biopsy of peripheral lung lesions.

Pilot study of archimedes virtual bronchoscopic navigation system-guided biopsy to diagnose lung nodules in children

BACKGROUND

Peripheral pulmonary lesions are uncommon in children. Bronchoscopy is a minimal invasive method to obtain a diagnostic lung biopsy. However, due to the lack of effective guidance methods, the diagnostic efficacy of transbronchial lung biopsy for peripheral solitary pulmonary diseases is still limited.

RESEARCH QUESTION

Is the Archimedes virtual bronchoscopic navigation system safe and effective for the diagnosis of peripheral pulmonary lesions in children?

STUDY DESIGN AND METHODS

This pilot study retrospectively analyzed the clinical features, radiological characteristics, operation processes, intra-and postoperative complications, and pathological results of five children who underwent Archimedes-guided biopsy of peripheral pulmonary lesions in Beijing Children's Hospital from May 2021 to May 2022.

RESULTS

The cohort comprised five children (all males) with age of 7.1-15.8 years. A guide sheath was inserted through the bronchoscope under the guidance of Archimedes combined with radial endobronchial ultrasound to complete the biopsy under general anesthesia. The fused fluoroscopy technique was used to reconfirm the location of the forceps prior to biopsy in all children. The forceps reached the lesion under the guidance of the navigation and the samples were collected successfully in all children. Pathological examination of the biopsy specimens showed Epstein-Barr virus infection-related lymphoproliferative disease in one child, pulmonary metastasis of rhabdomyosarcoma in one child, and pulmonary vasculitis in one child; high-throughput sequencing of the biopsy tissue sample identified Mycobacterium tuberculosis (sequence no. 80) in one child and Aspergillus (sequence no. 40) in another child. All five children tolerated the biopsy procedure without developing postoperative complications, such as pneumothorax and hemoptysis.

INTERPRETATION

Archimedes-guided bronchoscopic lung biopsy is a feasible and efficient way to diagnose peripheral pulmonary lesions in children with manageable complications.

NAVIGATE 24-Month Results: Electromagnetic navigation bronchoscopy for pulmonary lesions at 37 centers in Europe and the United States

INTRODUCTION

Electromagnetic navigation bronchoscopy (ENB) is a minimally invasive, image-guided approach to access lung lesions for biopsy or localization for treatment. However, no studies have reported prospective 24-month follow-up from a large, multinational, generalizable cohort. This study evaluated ENB safety, diagnostic yield, and usage patterns in an unrestricted, real-world observational design.

METHODS

The NAVIGATE single-arm, pragmatic cohort study (NCT02410837) enrolled subjects at 37 academic and community sites in 7 countries with prospective 24-month follow-up. Subjects underwent ENB using the superDimension navigation system versions 6.3 to 7.1. The prespecified primary endpoint was procedure-related pneumothorax requiring intervention or hospitalization.

RESULTS

A total of 1,388 subjects were enrolled for lung lesion biopsy (1,329; 95.7%), fiducial marker placement (272; 19.6%), dye marking (23; 1.7%), and/or lymph node biopsy (36; 2.6%). Concurrent endobronchial ultrasound-guided staging occurred in 456 subjects. General anesthesia (78.2% overall, 56.6% Europe, 81.4% US), radial endobronchial ultrasound (50.6%, 4.0%, 57.4%), fluoroscopy (85.0%, 41.7%, 91.0%), and rapid on-site evaluation use (61.7%, 17.3%, 68.5%) differed between regions. Pneumothorax and bronchopulmonary hemorrhage occurred in 4.7% and 2.7% of subjects, respectively (3.2% [primary endpoint] and 1.7% requiring intervention or hospitalization). Respiratory failure occurred in 0.6%. The diagnostic yield was 67.8% (range 61.9%-70.7%; 55.2% Europe, 69.8% US). Sensitivity for malignancy was 62.6%. Lung cancer clinical stage was I-II in 64.7% (55.3% Europe, 65.8% US).

CONCLUSIONS

Despite a heterogeneous cohort and regional differences in procedural techniques, ENB demonstrates low complications and a 67.8% diagnostic yield while allowing biopsy, staging, fiducial placement, and dye marking in a single procedure.

Advanced Bronchoscopic Technologies for Biopsy of the Pulmonary Nodule: A 2021 Review

The field of interventional pulmonology (IP) has grown from a fringe subspecialty utilized in only a few centers worldwide to a standard component in advanced medical centers. IP is increasingly recognized for its value in patient care and its ability to deliver minimally invasive and cost-effective diagnostics and treatments. This article will provide an in-depth review of advanced bronchoscopic technologies used by IP physicians focusing on pulmonary nodules. While most pulmonary nodules are benign, malignant nodules represent the earliest detectable manifestation of lung cancer. Lung cancer is the second most common and the deadliest cancer worldwide. Differentiating benign from malignant nodules is clinically challenging as these entities are often indistinguishable radiographically. Tissue biopsy is often required to discriminate benign from malignant nodule etiologies. A safe and accurate means of definitively differentiating benign from malignant nodules would be highly valuable for patients, and the medical system at large. This would translate into a greater number of early-stage cancer detections while reducing the burden of surgical resections for benign disease. There is little high-grade evidence to guide clinicians on optimal lung nodule tissue sampling modalities. The number of novel technologies available for this purpose has rapidly expanded over the last decade, making it difficult for clinicians to assess their efficacy. Unfortunately, there is a wide variety of methods used to determine the accuracy of these technologies, making comparisons across studies impossible. This paper will provide an in-depth review of available data regarding advanced bronchoscopic technologies.