Factors associated with the diagnostic yield of computed tomography-guided transbronchial lung biopsy

Feasibility of a Prototype Image Reconstruction Algorithm for Motion Correction in Interventional Cone-Beam CT Scans

RATIONALE AND OBJECTIVES

Assess the feasibility of a prototype image reconstruction algorithm in correcting motion artifacts in cone-beam computed tomography (CBCT) scans of interventional instruments in the lung.

MATERIALS AND METHODS

First, phantom experiments were performed to assess the algorithm, using the Xsight lung phantom with custom inserts containing straight or curved catheters. During scanning, the inserts moved in a continuous sinusoidal or breath-hold mimicking pattern, with varying amplitudes and frequencies. Subsequently, the algorithm was applied to CBCT data from navigation bronchoscopy procedures. The algorithm's performance was assessed quantitatively via edge-sharpness measurements and qualitatively by three specialists.

RESULTS

In the phantom study, the algorithm improved sharpness in 13 out of 14 continuous sinusoidal motion and five out of seven breath-hold mimicking scans, with more significant effects at larger motion amplitudes. Analysis of 27 clinical scans showed that the motion corrected reconstructions had significantly sharper edges than standard reconstructions (2.81 (2.24-6.46) vs. 2.80 (2.16-4.75), p = 0.003). These results were consistent with the qualitative assessment, which showed higher scores in the sharpness of bronchoscope-tissue interface and catheter-tissue interface in the motion-corrected reconstructions. However, the tumor demarcation ratings were inconsistent between raters, and the overall image quality of the new reconstructions was rated lower.

CONCLUSION

Our findings suggest that applying the new prototype algorithm for motion correction in CBCT images is feasible. The algorithm improved the sharpness of medical instruments in CBCT scans obtained during diagnostic navigation bronchoscopy procedures, which was demonstrated both quantitatively and qualitatively.

Imaging modalities during navigational bronchoscopy

INTRODUCTION

Lung nodules are commonly encountered in clinical practice. Technological advances in navigational bronchoscopy and imaging modalities have led to paradigm shift from nodule screening or follow-up to early lung cancer detection. This is due to improved nodule localization and biopsy confirmation with combined modalities of navigational platforms and imaging tools. To conduct this article, relevant literature was reviewed via PubMed from January 2014 until January 2024.

AREAS COVERED

This article highlights the literature on different imaging modalities combined with commonly used navigational platforms for diagnosis of peripheral lung nodules. Current limitations and future perspectives of imaging modalities will be discussed.

EXPERT OPINION

The development of navigational platforms improved localization of targets. However, published diagnostic yield remains lower compared to percutaneous-guided biopsy. The discordance between the actual location of lung nodule during the procedure and preprocedural CT chest is the main factor impacting accurate biopsies. The utilization of advanced imaging tools with navigation-based bronchoscopy has been shown to assist with localizing targets in real-time and improving biopsy success. However, it is important for interventional bronchoscopists to understand the strengths and limitations of these advanced imaging technologies.

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.

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.

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.

Cone-Beam CT Image Guidance With and Without Electromagnetic Navigation Bronchoscopy for Biopsy of Peripheral Pulmonary Lesions

BACKGROUND

Bronchoscopic diagnosis of small peripheral lung lesions suspected of lung cancer remains a challenge. A successful endobronchial diagnosis comprises navigation, confirmation, and tissue acquisition. In all steps, 3-dimensional information is essential. Cone-beam computed tomography (CBCT) imaging can provide computed tomography information and 3-dimensional augmented fluoroscopy imaging. We assessed whether CBCT imaging can improve navigation and diagnosis of peripheral lesions by 2 clinical workflows with a cross-over design: (1) a primary CBCT and radial endobronchial ultrasound mini probe imaging-based approach and (2) a primary electromagnetic navigation (EMN) and radial endobronchial ultrasound mini probe imaging-based approach.

METHODS

All patients with a peripheral lung lesion biopsy indication were eligible for study inclusion and randomly assigned to study arms. Commercially available equipment was used. The main study goals were to assess CBCT-confirmed navigation success and diagnostic accuracy. Surgery or unambiguous clinical follow-up served as the gold standard.

RESULTS

Eighty-seven patients with 107 lesions were included. Lesion mean longest axis size in the CBCT arm was 16.6 mm (n=47) and 14.2 mm in the EMN arm (n=40). The primary CBCT approach and primary EMN approach had 76.3% and 52.2% navigation success, respectively. Addition of EMN to the CBCT approach increased navigation success to 89.9%. Addition of CBCT imaging to the EMN approach significantly increased navigation success to 87.5% per lesion. The overall diagnostic accuracy per patient was significantly lower than the navigation success, being 72.4%.

CONCLUSION

CBCT imaging is a valuable addition to navigation bronchoscopy. Although overall navigation success was high, the diagnostic accuracy remains to be improved. Future research should focus on improving the tissue acquisition methodology.

Cone beam CT imaging for bronchoscopy: a technical review

Cone beam computed tomography (CBCT) is a well-established imaging modality with numerous proven applications across multiple clinical disciplines. More recently, CBCT has emerged as an important imaging tool for bronchoscopists, primarily used during transbronchial biopsy of peripheral pulmonary lesions (PPLS). For this application CBCT has proved useful in navigating devices to a target lesion, in confirming device tool-in-lesion, as well as during tissue acquisition. In addition, CBCT is poised to play an important role in trials evaluating bronchoscopic ablation by helping to determine the location of the ablative probe relative to the target lesion. Before adopting this technology, it is key for bronchoscopists to learn some basic concepts that will allow them to have a safer and more successful experience with CBCT. Hence, in the current manuscript, we will focus on both technical and practical aspects of CBCT imaging, ranging from systems considerations, image quality, radiation dose and dose-reduction strategies, procedure room set-up, and best practices for CBCT image acquisition.

Bronchoscopic Diagnostic Procedures Available to the Pulmonologist

In the diagnosis of lung cancer, pulmonologists have several tools at their disposal. From the tried and true convex probe endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration to robotic bronchoscopy for peripheral lesions and new technology to unblind the biopsy tools, this article elucidates and expounds on the tools currently available and being developed for lung cancer diagnosis.

Robot-assisted bronchoscopy for pulmonary lesion diagnosis: results from the initial multicenter experience

Background

The Robotic Endoscopic System (Auris Health, Inc., Redwood City, CA) has the potential to overcome several limitations of contemporary guided-bronchoscopic technologies for the diagnosis of lung lesions. Our objective is to report on the initial post-marketing feasibility, safety and diagnostic yield of this technology.

Methods

We retrospectively reviewed data on consecutive cases in which robot-assisted bronchoscopy was used to sample lung lesions at four centers in the US (academic and community) from June 15th, 2018 to December 15th, 2018.

Results

One hundred and sixty-seven lesions in 165 patients were included in the analysis, with an average follow-up of 185 ± 55 days. The average size of target lesions was 25.0 ± 15.0 mm. Seventy-one percent were located in the peripheral third of the lung. Pneumothorax and airway bleeding occurred in 3.6 and 2.4% cases, respectively. Navigation was successful in 88.6% of cases. Tissue samples were successfully obtained in 98.8%. The diagnostic yield estimates ranged from 69.1 to 77% assuming the cases of biopsy-proven inflammation without any follow-up information (N = 13) were non-diagnostic and diagnostic, respectively. The yield was 81.5, 71.7 and 26.9% for concentric, eccentric and absent r-EBUS views, respectively. Diagnostic yield was not affected by lesion size, density, lobar location or centrality.

Conclusions

RAB implementation in community and academic centers is safe and feasible, with an initial diagnostic yield of 69.1–77% in patients with lung lesions that require diagnostic bronchoscopy. Comparative trials with the existing bronchoscopic technologies are needed to determine cost-effectiveness of this technology.

Computed Tomography Bronchus Sign and the Diagnostic Yield of Guided Bronchoscopy for Peripheral Pulmonary Lesions. A Systematic Review and Meta-Analysis

RATIONALE

Indeterminate peripheral pulmonary lesions (PPLs) often require tissue diagnosis. If nonsurgical biopsy techniques are considered, deciding between bronchoscopic transbronchial versus computed tomography-guided transthoracic biopsy can be difficult. The former has a low diagnostic yield with a low complication risk, whereas the latter has a better diagnostic yield but a higher complication rate. Investigators have looked at various lesion characteristics that can predict the diagnostic yield of guided bronchoscopic biopsies. Although consensus exists that larger size and proximity to the hilum increase the diagnostic yield, there is ongoing debate about the association between computed tomography bronchus sign (air-filled bronchus in close proximity of the lesion as seen on computed tomography imaging) and the diagnostic yield of guided bronchoscopic modalities.

OBJECTIVES

To perform a meta-analysis and systematic review, determining the association between computed tomography bronchus sign and the diagnostic yield of guided bronchoscopy for PPLs.

METHODS

MEDLINE, Embase, Scopus, and Google Scholar were searched in January 2018 for guided bronchoscopy studies that had assessed the impact of computed tomography bronchus sign on the diagnostic yield. The quality of included studies was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 tool. Meta-analysis was performed using MedCalc (version 18). Odds ratios were used to compare yield of lesions with and without bronchus sign. Random effects model was used when significant heterogeneity was observed (I² > 40%).

RESULTS

For 2,199 lesions with computed tomography bronchus sign, the overall weighted diagnostic yield was 74.1% (95% confidence interval, 68.3-79.5%). For 971 lesions without computed tomography bronchus sign, the overall weighted diagnostic yield was 49.6% (95% confidence interval, 39.6-59.5%). The odds ratio for successfully diagnosing a lesion with computed tomography bronchus sign was 3.4 (95% confidence interval, 2.4-5.0). Possible sources of heterogeneity in the meta-analysis included differences in study designs, guidance modalities, and cancer prevalence. The odds ratio for successfully diagnosing a lesion with computed tomography bronchus sign was relatively lower for prospective studies.

CONCLUSIONS

PPLs with computed tomography bronchus sign are more likely to be diagnosed with guided bronchoscopy than the lesions without computed tomography bronchus sign. Clinicians should consider this, along with the lesion size and distance from the hilum, when contemplating guided bronchoscopy for PPLs.

Diagnostic value of rapid on-site evaluation during transbronchial biopsy for peripheral lung cancer

BACKGROUND

An increasing number of pulmonary lesions-particularly, peripheral lung lesions-are identified with current technological advancements. Notably, the yield of traditional bronchoscopy for the diagnosis of peripheral lung lesions is low. This study evaluated the diagnostic value of rapid on-site evaluation (ROSE) during transbronchial biopsy for peripheral lung cancer.

METHODS

This study included 641 patients who underwent transbronchial biopsy for suspected lung cancer at the Respiratory Department of Tianjin Medical University General Hospital between January 2012 and December 2016. Based on whether ROSE was used, patients were assigned to the ROSE group (353 patients) or non-ROSE group (288 patients). In the ROSE group, several air-dried smears were processed with Diff-Quik staining; the remaining samples were placed in 10% formalin. Diagnostic yields for central and peripheral lung cancer were compared between the two groups. In addition, ROSE results were compared with final diagnoses.

RESULTS

Diagnostic yield for peripheral lung cancer, stratified by pathology, was significantly higher in the ROSE group than in the non-ROSE group (42.9% vs. 30.7%, P < 0.05). The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of ROSE for peripheral pulmonary lesions were 90.0%, 89.5%, 94.0%, 82.8% and 89.8%, respectively. Conformance was high between ROSE and final pathologic evaluations during transbronchial biopsy (Kappa = 0.780, P = 0.035). There were no procedure-related deaths.

CONCLUSIONS

ROSE during conventional transbronchial biopsy improves diagnostic yield, stratified by pathology, for patients with peripheral lung cancer via live feedback. Moreover, ROSE diagnosis correlates with final cytopathological diagnosis.

Using the Hybrid Operating Room in Thoracic Surgery: A Paradigm Shift

We describe the integration of the hybrid operation room cone-beam computed tomography (CT) scan technology into the practice of general thoracic surgery. The combination of the following three techniques: (1) cone-beam CT scan augmented navigational bronchoscopy, (2) cone-beam CT-guided percutaneous biopsy and/or fiducial placement, and (3) fiducial or image-guided video-assisted thoracic surgery resection, into a single-stage, single-provider procedure allows for diagnosis and treatment in one setting. Rapid on-site evaluation of cytological or pathology specimens is key to this "all-in-one" approach. The time from diagnosis to curative treatment can significantly be reduced using the hybrid operation room technology, leading to decreased upstaging, increased survival and facilitating the otherwise difficult intraoperative detection and resection of small and deeper lesions. Not only does this benefit the overall thoracic healthcare of the community but also provides a cost-effective paradigm for the institution.

Cone-Beam CT With Augmented Fluoroscopy Combined With Electromagnetic Navigation Bronchoscopy for Biopsy of Pulmonary Nodules

BACKGROUND

Electromagnetic navigation bronchoscopy (ENB) has been widely adopted as a guidance technique for biopsy of peripheral lung nodules. However, ENB is limited by the lack of real-time confirmation of the biopsy devices. Intraprocedural cone-beam computed tomography (CBCT) imaging can be utilized to assess or confirm the location of biopsy devices. The aim of this study is to determine the safety and diagnostic yield (DY) of image fusion of intraprocedural CBCT data with live fluoroscopy (augmented fluoroscopy) during ENB-guided biopsy of peripheral lung nodules.

METHODS

Data from 75 consecutive patients who underwent biopsy with ENB was collected retrospectively. Patients underwent CBCT imaging while temporarily suspending mechanical ventilation. CBCT data were acquired and 3-dimensional segmentation of nodules was performed using commercially available software (OncoSuite). During ENB, the segmented lesions were projected and fused with live fluoroscopy enabling real-time 3-dimensional guidance.

RESULTS

A total of 93 lesions with a median size of 16.0 mm were biopsied in 75 consecutive patients. The overall DY by lesion was 83.7% (95% confidence interval, 74.8%-89.9%). Multivariate regression analysis showed no independent correlation between lesion size, lesion location, lesion visibility under standard fluoroscopy, and the presence of a bronchus sign with DY. Pneumothorax occurred in 3 patients (4%).

CONCLUSION

Intraprocedural CBCT imaging with augmented fluoroscopy is feasible and effective and is associated with high DY during ENB-guided biopsies.

Cone beam computed tomography-guided thin/ultrathin bronchoscopy for diagnosis of peripheral lung nodules: a prospective pilot study

Background

Despite advances in bronchoscopy, its diagnostic yield for peripheral lung lesions continues to be suboptimal. Cone beam computed tomography (CBCT) could be utilized to corroborate the accuracy of our bronchoscopic navigation and hopefully increase its diagnostic yield. However, data on radiation exposure and feasibility of CBCT-guided bronchoscopy is scarce.

Methods

Prospective pilot study of bronchoscopy for peripheral lung nodules under general anesthesia with thin/ultrathin bronchoscope, radial-probe endobronchial ultrasound (RP-EBUS), and CBCT. Main objective was to estimate radiation dose and secondary objective was the additional value of CBCT in terms of navigational and diagnostic yield.

Results

A total of 20 patients were enrolled. Median lesion size was 2.1 (range, 1.1-3) cm and distance from pleura was 2.1 (range, 0-2.8) cm. "Bronchus sign" was present in 12 (60%) of the lesions. Totally, 12 lesions (60%) were invisible on fluoroscopy. CBCT identified atelectasis obscuring the target in 4 cases (20%). Eleven patients (55%) underwent 1 CBCT scan and 9 patients (45%) 2. The mean estimated effective dose (E) to patients resulting from CBCT ranged between 8.6 and 23 mSv, depending on utilized conversion factors. Both pre-CBCT navigation and diagnostic yield were 50%. Additional post-CBCT maneuvers increased navigation yield to 75% (P=0.02) and diagnostic yield to 70% (P=0.04). One patient developed a pneumothorax.

Conclusions

CBCT-guided bronchoscopy is associated with an acceptable radiation dose. CBCT may potentially increase both navigation and diagnostic yield of thin/ultrathin bronchoscopy for peripheral lung nodules. The above findings as well as the incidental but relevant finding of intra-procedural atelectasis need to be confirmed in larger prospective studies.

Trial registration

This study is registered in ClinicalTrials.gov as number NCT02978170.

Towards an optimization of bronchoscopic approaches to the diagnosis and treatment of the pulmonary nodules: a review

The last several years have seen substantive improvements and innovation with respect to bronchoscopic approaches to the indeterminate pulmonary nodule both diagnostically and therapeutically. Indeed, these advances have only accelerated over the last year or two and extend across multiple domains and include improvements in imaging technologies and techniques, approaches and tools to access different areas of the lung, tools to acquire tissue as well as tools and methods to ablate tissue. Needless to say, there are a variety of different approaches in terms of how these issues are being solved along with differing levels of technology and infrastructure commitments necessary to utilize these various tools, with some of these approaches being farther along than others. This article reviews some of these recent advances in the domains of advanced imaging, approaches to accessing various parts of the lung, tools designed to acquire tissue, robotic endoscopy platforms, new approaches to tissue ablation as well as potential additions to these areas that are on the horizon.