Cone beam CT imaging for bronchoscopy: a technical review

Cone-Beam Computed Tomography Improves Location of Transbronchial Cryobiopsy in Interstitial Lung Disease with Limited Extent

INTRODUCTION

Transbronchial lung cryobiopsy has been recommended as an acceptable alternative to surgical approach for making a histopathological diagnosis in patients with interstitial lung disease (ILD) of undetermined type. In limited diseases (especially if distributed along the subpleural region), sampling the specific area in which the pathological process is more represented could be challenging. Aim of the study was to determine the potential benefit of utilizing cone-beam computed tomography-guided cryobiopsy in patients with limited extent of ILD on CT scan and determine the single impact of each sequential biopsy progressively increasing the total number of biopsies.

METHODS

This study is a prospective analysis of patients with undetermined ILD and CT scan extent <15% undergoing cone-beam CT-guided cryobiopsy. Each biopsy sample was collected and processed individually and pathologic interpretations were performed sequentially with the pathologist reformulating a new report with the addition of each sample (cumulative yield).

RESULTS

Thirty six patients were enrolled. Pathological diagnostic yield was >90%, with almost 80% of diagnostic samples being the first one; when a second biopsy was performed, mean diagnostic yield increased with only a moderately significant difference. No severe adverse events were observed; pneumothorax was documented in 27.8% of the cases.

CONCLUSION

Sequential individual collection and pathologic interpretation of each biopsy sample has confirmed the possibility of obtaining a diagnostic specimen at the first pass if transbronchial cryobiopsy is performed under cone-beam CT.

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.

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.

Cone Beam CT Derived Laser-Guided Percutaneous Lung Ablation: Minimizing Needle-Related Complications Under General Anesthesia with Lung Separation

RATIONALE AND OBJECTIVES

Percutaneous lung tumor ablations are mostly performed in computed tomography (CT) rooms under local anesthesia with conscious sedation. However, maintaining the breath-hold phase during this can be challenging, affecting image quality and increasing complications. With the advent of hybrid operating rooms (HORs), this procedure can be performed with endotracheal tube (ETGA) intubation under general anesthesia with lung separation, ensuring precise imaging in a single-stage setting. Lung separation provides surgical exposure of one lung while ensuring ample gas exchange with the other. This study evaluated tumor ablations performed in an HOR equipped with cone beam CT and laser guidance.

MATERIALS AND METHODS

This retrospective study included patients who underwent lung tumor ablation under general anesthesia with an ETGA in an HOR between July 2020 and May 2023. Anesthesia considerations, perioperative management, and postoperative follow-ups were evaluated.

RESULTS

65 patients (78 tumors) underwent ablation using two types of lung ventilation methods including a single-lumen tube with a blocker (SLT/BL) (n = 15) and double-lumen tube (DLT) (n = 50). Most patients experienced desaturation during the apnea phase of dynamic CT and needling. The average SpO2 value was significantly lower in the DLT group than in the SLT/BL group during the procedure (81.1% versus 88.7%, P = 0.033). Five, three, and two patients developed pneumothorax, subcutaneous emphysema, and pleural effusion, respectively.

CONCLUSION

Percutaneous ablation under general anesthesia with endotracheal intubation and lung separation performed in HORs was feasible and safe. The setup minimized complication risks and maintained a balance between patient safety and successful procedures.

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.

Novel Deep Learning Denoising Enhances Image Quality and Lowers Radiation Exposure in Interventional Bronchial Artery Embolization Cone Beam CT

OBJECTIVES

In interventional bronchial artery embolization (BAE), periprocedural cone beam CT (CBCT) improves guiding and localization. However, a trade-off exists between 6-second runs (high radiation dose and motion artifacts, but low noise) and 3-second runs (vice versa). This study aimed to determine the efficacy of an advanced deep learning denoising (DLD) technique in mitigating the trade-offs related to radiation dose and image quality during interventional BAE CBCT.

MATERIALS AND METHODS

This study included BMI-matched patients undergoing 6-second and 3-second BAE CBCT scans. The dose-area product values (DAP) were obtained. All datasets were reconstructed using standard weighted filtered back projection (OR) and a novel DLD software. Objective image metrics were derived from place-consistent regions of interest, including CT numbers of the Aorta and lung, noise, and contrast-to-noise ratio. Three blinded radiologists performed subjective assessments regarding image quality, sharpness, contrast, and motion artifacts on all dataset combinations in a forced-choice setup (-1 = inferior, 0 = equal; 1 = superior). The points were averaged per item for a total score. Statistical analysis ensued using a properly corrected mixed-effects model with post hoc pairwise comparisons.

RESULTS

Sixty patients were assessed in 30 matched pairs (age 64 ± 15 years; 10 female). The mean DAP for the 6 s and 3 s runs was 2199 ± 185 µGym² and 1227 ± 90 µGym², respectively. Neither low-dose imaging nor the reconstruction method introduced a significant HU shift (p ≥ 0.127). The 3 s-DLD presented the least noise and superior contrast-to-noise ratio (CNR) (p < 0.001). While subjective evaluation revealed no noticeable distinction between 6 s-DLD and 3 s-DLD in terms of quality (p ≥ 0.996), both outperformed the OR variants (p < 0.001). The 3 s datasets exhibited fewer motion artifacts than the 6 s datasets (p < 0.001).

CONCLUSIONS

DLD effectively mitigates the trade-off between radiation dose, image noise, and motion artifact burden in regular reconstructed BAE CBCT by enabling diagnostic scans with low radiation exposure and inherently low motion artifact burden at short examination times.

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.

Virtual bronchoscopic navigation with intraoperative cone-beam CT for the diagnosis of peripheral pulmonary nodules

OBJECTIVE

Transbronchial biopsy is a safe manner with fewer complications than percutaneous transthoracic needle biopsy; however, the current diagnostic yield is still necessitating further improvement. We aimed to evaluate the diagnostic yield of using virtual bronchoscopic navigation (VBN) and cone-beam CT (CBCT) for transbronchial biopsy and to investigate the factors that affected the diagnostic sensitivity.

METHODS

We retrospectively investigated 255 patients who underwent VBN-CBCT-guided transbronchial biopsy at our two centers from May 2021 to April 2022. A total of 228 patients with final diagnoses were studied. Patient characteristics including lesion size, lesion location, presence of bronchus sign, lesion type and imaging tool used were collected and analyzed. Diagnostic yield was reported overall and in groups using different imaging tools.

RESULTS

The median size of lesion was 21 mm (range of 15.5-29 mm) with 46.1% less than 2 cm in diameter. Bronchus sign was present in 87.7% of the patients. The overall diagnostic yield was 82.1%, and sensitivity for malignancy was 66.3%. Patients with lesion > 2 cm or with bronchus sign were shown to have a significantly higher diagnostic yield. Four patients had bleeding and no pneumothorax occurred.

CONCLUSION

Guided bronchoscopy with VBN and CBCT was an effective diagnostic method and was associated with a high diagnostic yield in a safe manner. In addition, the multivariant analysis suggested that lesion size and presence of bronchus sign could be a predictive factor for successful bronchoscopic diagnosis.

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.

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.

Cone-Beam Computed Tomography-Guided Cryobiopsy Combined with Conventional Biopsy for Ground Glass Opacity-Predominant Pulmonary Nodules

INTRODUCTION

Cryobiopsy (CB) using a 1.1-mm cryoprobe under fluoroscopic guidance is feasible and safe for diagnosis of ground glass opacity (GGO) lesions. However, the efficacy of CB combined with cone-beam CT (CBCT) for GGO-predominant pulmonary nodules remains elusive.

METHODS

We retrospectively studied patients who underwent CB combined with conventional biopsy under CBCT guidance for GGO-predominant pulmonary nodules with a consolidation-to-tumour ratio <50.0%.

RESULTS

A total of 32 patients with GGO-predominant pulmonary nodules were enrolled: 17 pure GGOs and 15 mixed GGOs. The mean lesion diameter was 15.81 ± 5.52 mm and the overall diagnostic yield was 71.9%. Seven lesions were diagnosed by CB alone, which increased the diagnostic outcomes by 21.9%. Diagnostic yields for CB, forceps biopsy (FB), brushing, and guide sheath flushing were 65.6%, 46.9%, 15.6%, and 14.3%, respectively. Univariate analysis revealed that positive computed tomography (CT) bronchus sign (p = 0.035), positive CBCT sign (p < 0.01), and CB-first biopsy sequence (p = 0.036) were significant predictive factors for higher diagnostic yield. Specimens obtained by CB had larger mean sample size (p < 0.01), lower blood cell area (p < 0.01), and fewer crush artefacts (p < 0.01) than specimens from FB. No severe bleeding or other complications occurred.

CONCLUSION

CB using a 1.1-mm cryoprobe under CBCT guidance increased diagnostic yield for GGO-predominant pulmonary nodules based on conventional biopsy. Further, it provided larger and nearly intact samples compared with forceps.

[Advanced bronchoscopic techniques for the diagnosis of peripheral lung nodule]

The endoscopic diagnosis of peripheral lung nodules is a challenging aspect of oncological practice. More often than not inaccessible by traditional endoscopy, these nodules necessitate multiple imagery tests, as well as diagnostic surgery for benign lesions. Even though transthoracic ultrasonography has a high diagnostic yield, a sizeable complication rate renders it suboptimal. Over recent years, a number of safe and accurate navigational bronchoscopic procedures have been developed. In this first part, we provide an overview of the bronchoscopic techniques currently applied for the excision and diagnostic analysis of peripheral lung nodules; emphasis is laid on electromagnetic navigation bronchoscopy and the association of virtual bronchoscopy planner with radial endobronchial ultrasound. We conclude by considering recent innovations, notably 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.

High risk lung nodule: A multidisciplinary approach to diagnosis and management

Pulmonary nodules are often discovered incidentally during CT scans performed for other reasons. While the vast majority of nodules are benign, a small percentage may represent early-stage lung cancer with the potential for curative treatments. With the growing use of CT for both clinical purposes and lung cancer screening, the number of pulmonary nodules detected is expected to increase substantially. Despite well-established guidelines, many nodules do not receive proper evaluation due to a variety of factors, including inadequate coordination of care and financial and social barriers. To address this quality gap, novel approaches such as multidisciplinary nodule clinics and multidisciplinary boards may be necessary. As pulmonary nodules may indicate early-stage lung cancer, it is crucial to adopt a risk-stratified approach to identify potential lung cancers at an early stage, while minimizing the risk of harm and expense associated with over investigation of low-risk nodules. This article, authored by multiple specialists involved in nodule management, delves into the diagnostic approach to lung nodules. It covers the process of determining whether a patient requires tissue sampling or continued surveillance. Additionally, the article provides an in-depth examination of the various biopsy and therapeutic options available for malignant lung nodules. The article also emphasizes the significance of early detection in reducing lung cancer mortality, especially among high-risk populations. Furthermore, it addresses the creation of a comprehensive lung nodule program, which involves smoking cessation, lung cancer screening, and systematic evaluation and follow-up of both incidental and screen-detected nodules.

Immediate and Follow-up Imaging Findings after Cone-Beam CT-guided Transbronchial Lung Cryobiopsy

Purpose

To evaluate findings after transbronchial lung cryobiopsy (TBLC) using intraprocedural cone-beam CT (CBCT) and follow-up chest CT examinations.

Materials and Methods

A single-center, prospective cohort study was performed with 14 participants (mean age, 65 years ± 13 [SD]; eight male participants) undergoing CBCT-guided TBLC between August 2020 and February 2021 who underwent follow-up chest CT imaging. Intraprocedural CBCT and follow-up chest CT images were interpreted for changes compared with baseline CT images. Statistical analyses were performed using independent samples t test and analysis of variance.

Results

A total of 62 biopsies were performed, with 48 in the field of view of CBCT immediately after biopsy. All 48 biopsy sites had evidence of postprocedural hemorrhage, and 17 (35%) had pneumatoceles at the biopsy site. Follow-up CT images showed resolution of these findings. Solid nodules developed at 18 of the 62 (29%) biopsy sites.

Conclusion

Postbiopsy hemorrhage and pneumatoceles on intraprocedural CBCT images (which were clinically occult and resolved spontaneously) and new solid nodules on follow-up chest CT images were commonly observed after TBLC. These findings may help alleviate unnecessary follow-up imaging and tissue sampling.Keywords: Biopsy/Needle Aspiration, CT, Lungs, Lung Biopsy, Interventional Bronchoscopy© RSNA, 2023.

Cone-Beam Computed-Tomography-Derived Augmented Fluoroscopy-Guided Biopsy for Peripheral Pulmonary Nodules in a Hybrid Operating Room: A Case Series

Lung cancer is the most lethal cancer type in Taiwan and worldwide. Early detection and treatment advancements have improved survival. However, small peripheral pulmonary nodules (PPN) biopsy is often challenging, relying solely on bronchoscopy with radial endobronchial ultrasound (EBUS). Augmented fluoroscopy overlays the intra-procedural cone-beam computed tomography (CBCT) images with fluoroscopy enabling real-time three-dimensional localization during bronchoscopic transbronchial biopsy. The hybrid operating room (HOR), equipped with various types of C-arm CBCT, is a perfect suite for PPN diagnosis and other interventional pulmonology. This study shares the single institute experience of EBUS transbronchial biopsy of PPN with the aid of augmented fluoroscopic bronchoscopy (AFB) and CBCT in an HOR. We retrospectively enrolled patients who underwent robotic CBCT, augmented fluoroscopy-guided, radial endobronchial ultrasound-confirmed transbronchial biopsy and cryobiopsy in a hybrid operating room. Patient demographic characteristics, computed tomography images, rapid on-site evaluation cytology, and final pathology reports were collected. Forty-one patients underwent transbronchial biopsy and 6 received additional percutaneous transthoracic core-needle biopsy during the same procedure. The overall diagnostic yield was 88%. The complications included three patients with pneumothorax after receiving subsequent CT-guided percutaneous transthoracic needle biopsy, and two patients with hemothorax who underwent transbronchial cryobiopsy. Overall, the bronchoscopic biopsy of PPN using AFB and CBCT as precise guidance in the hybrid operating room is feasible and can be performed safely with a high diagnostic yield.

Mobile Cone-Beam CT-Assisted Bronchoscopy for Peripheral Lung Lesions

Peripheral bronchoscopy with the use of thin/ultrathin bronchoscopes and radial-probe endobronchial ultrasound (RP-EBUS) has been associated with a fair diagnostic yield. Mobile cone-beam CT (m-CBCT) could potentially improve the performance of these readily available technologies. We retrospectively reviewed the records of patients undergoing bronchoscopy for peripheral lung lesions with thin/ultrathin scope, RP-EBUS, and m-CBCT guidance. We studied the performance (diagnostic yield and sensitivity for malignancy) and safety (complications, radiation exposure) of this combined approach. A total of 51 patients were studied. The mean target size was 2.6 cm (SD, 1.3 cm) and the mean distance to the pleura was 1.5 cm (SD, 1.4 cm). The diagnostic yield was 78.4% (95 CI, 67.1-89.7%), and the sensitivity for malignancy was 77.4% (95 CI, 62.7-92.1%). The only complication was one pneumothorax. The median fluoroscopy time was 11.2 min (range, 2.9-42.1) and the median number of CT spins was 1 (range, 1-5). The mean Dose Area Product from the total exposure was 41.92 Gy·cm² (SD, 11.35 Gy·cm²). Mobile CBCT guidance may increase the performance of thin/ultrathin bronchoscopy for peripheral lung lesions in a safe manner. Further prospective studies are needed to corroborate these findings.

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.

Shape-Sensing Robotic-Assisted Bronchoscopy with Concurrent use of Radial Endobronchial Ultrasound and Cone Beam Computed Tomography in the Evaluation of Pulmonary Lesions

PURPOSE

Lung nodules are a common radiographic finding. Non-surgical biopsy is recommended in patients with moderate or high pretest probability for malignancy. Shape-sensing robotic-assisted bronchoscopy (ssRAB) combined with radial endobronchial ultrasound (r-EBUS) and cone beam computed tomography (CBCT) is a new approach to sample pulmonary lesions. Limited data are available regarding the diagnostic accuracy of combined ssRAB with r-EBUS and CBCT.

METHODS

We conducted a retrospective analysis of the first 200 biopsy procedures of 209 lung lesions using ssRAB, r-EBUS, and CBCT at UT Southwestern Medical Center in Dallas, Texas. Outcomes were based on pathology interpretations of samples taken during ssRAB, clinical and radiographic follow-up, and/or additional sampling.

RESULTS

The mean largest lesion dimension was 22.6 ± 13.3 mm with a median of 19 mm (range 7 to 73 mm). The prevalence of malignancy in our data was 64.1%. The diagnostic accuracy of ssRAB combined with advanced imaging was 91.4% (CI 86.7-94.8%). Sensitivity was 87.3% (CI 80.5-92.4%) with a specificity of 98.7% (CI 92.8-100%). The negative and positive predictive values were 81.3% and 99.2%. The rate of non-diagnostic sampling was 11% (23/209 samples). The only complication was pneumothorax in 1% (2/200 procedures), with 0.5% requiring a chest tube.

CONCLUSION

Our results of the combined use of ssRAB with r-EBUS and CBCT to sample pulmonary lesions suggest a high diagnostic accuracy for malignant lesions with reasonably high sensitivity and negative predictive values. The procedure is safe with a low rate of complications.

Diagnosis of Organizing Pneumonia with an Ultrathin Bronchoscope and Cone-Beam CT: A Case Report

Organizing pneumonia (OP) is a pulmonary disease histopathologically characterized by plugs of loose connective tissue in distal airways. The clinical and radiological presentations are not specific and they usually require a biopsy confirmation. This paper presents the case of a patient with a pulmonary opacity sampled with a combined technique of ultrathin bronchoscopy and cone-beam CT. A 64-year-old female, a former smoker, was admitted to the hospital of Reggio Emilia (Italy) for exertional dyspnea and a dry cough without a fever. The history of the patient included primary Sjögren Syndrome interstitial lung disease (pSS-ILD) characterized by a non-specific interstitial pneumonia (NSIP) radiological pattern; this condition was successfully treated up to 18 months before the new admission. The CT scan showed the appearance of a right lower lobe pulmonary opacity of an uncertain origin that required a histological exam for the diagnosis. The lung lesion was difficult to reach with traditional bronchoscopy and a percutaneous approach was excluded. Thus, cone-beam CT, augmented fluoroscopy and ultrathin bronchoscopy were chosen to collect a tissue sample. The histopathological exam was suggestive of OP, a condition occurring in 4-11% of primary Sjögren Syndrome cases. This case showed that, in the correct clinical and radiological context, even biopsies taken with small forceps can lead to a diagnosis of OP. Moreover, it underlined that the combination of multiple advanced technologies in the same procedure can help to reach difficult target lesions, providing proper samples for a histological diagnosis.

Source-detector trajectory optimization in cone-beam computed tomography: a comprehensive review on today’s state-of-the-art

Cone-beam computed tomography (CBCT) imaging is becoming increasingly important for a wide range of applications such as image-guided surgery, image-guided radiation therapy as well as diagnostic imaging such as breast and orthopaedic imaging. The potential benefits of non-circular source-detector trajectories was recognized in early work to improve the completeness of CBCT sampling and extend the field of view (FOV). Another important feature of interventional imaging is that prior knowledge of patient anatomy such as a preoperative CBCT or prior CT is commonly available. This provides the opportunity to integrate such prior information into the image acquisition process by customized CBCT source-detector trajectories. Such customized trajectories can be designed in order to optimize task-specific imaging performance, providing intervention or patient-specific imaging settings. The recently developed robotic CBCT C-arms as well as novel multi-source CBCT imaging systems with additional degrees of freedom provide the possibility to largely expand the scanning geometries beyond the conventional circular source-detector trajectory. This recent development has inspired the research community to innovate enhanced image quality by modifying image geometry, as opposed to hardware or algorithms. The recently proposed techniques in this field facilitate image quality improvement, FOV extension, radiation dose reduction, metal artifact reduction as well as 3D imaging under kinematic constraints. Because of the great practical value and the increasing importance of CBCT imaging in image-guided therapy for clinical and preclinical applications as well as in industry, this paper focuses on the review and discussion of the available literature in the CBCT trajectory optimization field. To the best of our knowledge, this paper is the first study that provides an exhaustive literature review regarding customized CBCT algorithms and tries to update the community with the clarification of in-depth information on the current progress and future trends.

Nodules, Navigation, Robotic Bronchoscopy, and Real-Time Imaging

The process of detection, diagnosis, and management of lung nodules is complex due to the heterogeneity of lung pathology and a relatively low malignancy rate. Technological advances in bronchoscopy have led to less-invasive diagnostic procedures and advances in imaging technology have helped to improve nodule localization and biopsy confirmation. Future research is required to determine which modality or combination of complimentary modalities is best suited for safe, accurate, and cost-effective management of lung nodules.

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 augmented fluoroscopy allows safe and efficient diagnosis of a difficult lung nodule

Background

Detection of small peripheral lung nodules is constantly increasing with the development of low dose computed tomography lung cancer screening programs. A tissue diagnosis is often required to confirm malignity, with endobronchial biopsies being associated with a lower pneumothorax rate than percutaneous approaches. Endoscopic diagnosis of peripheral small size lung nodules is however often challenging using traditional bronchoscopy and endobronchial ultrasound alone. New virtual bronchoscopic navigation techniques such as electromagnetic navigational bronchoscopy (ENB) have developed to improve peripheral navigation, with diagnostic yield however remaining in the 30–50% range for small lesions. Recent studies have shown the benefits of combining Cone beam computed tomography (CBCT) with ENB to improve diagnostic yield to up to 83%. The use of ENB however remains limited by disposable cost, bronchus sign dependency and inaccuracies due to CT to body divergence.

Case presentation

This case report highlights the feasibility and usefulness of CBCT-guided bronchoscopy for the sampling of lung nodules difficult to reach through traditional bronchoscopy because of nodule size and peripheral position. Procedure was scheduled in a mobile robotic hybrid operating room with patient under general anaesthesia. CBCT acquisition was performed to localize the target lesion and plan the best path to reach it into bronchial tree. A dedicated software was used to segment the lesion and the bronchial path which 3D outlines were automatically fused in real time on the fluoroscopic images to augment live guidance. Navigation to the lesion was guided with bronchoscopy and augmented fluoroscopy alone. Before the sampling, CBCT imaging was repeated to confirm the proper position of the instrument into the lesion. Four transbronchial needle aspirations (TBNA) were performed and the tissue analysis showed a primary lung adenocarcinoma.

Conclusions

CBCT and augmented fluoroscopy technique is a safe and effective and has potential to improve early stage peripheral lesions endobronchial diagnostic yield without ENB. Additional studies are warranted to confirm its safety, efficacy and technical benefits, both for diagnosis of oncological and non-oncological disease and for endobronchial treatment of inoperable patients.

Advanced bronchoscopic techniques for the diagnosis and treatment of peripheral lung cancer

Lung cancer is the leading cause of cancer related deaths worldwide. As a result of the increasing use of chest CT scans and lung cancer screening initiatives, there is a rapidly increasing need for lung lesion analysis and - in case of confirmed cancer - treatment. A desirable future concept is the one-stop outpatient bronchoscopic approach including navigation to the tumor, malignancy confirmation and immediate treatment. Several novel bronchoscopic diagnostic and treatment concepts are currently under evaluation contributing to this concept. As the majority of suspected malignant lung lesions develop in the periphery of the lungs, improved bronchoscopic navigation to the target lesion is of key importance. Fortunately, the field of interventional pulmonology is evolving rapidly and several advanced bronchoscopic navigation techniques are clinically available, allowing an increasingly accurate tissue diagnosis of peripheral lung lesions. Additionally, multiple bronchoscopic treatment modalities are currently under investigation. This review will provide a concise overview of advanced bronchoscopic techniques to diagnose and treat peripheral lung cancer by describing their working mechanisms, strengths and weaknesses, identifying knowledge gaps and indicating future developments. The desired one-step concept of bronchoscopic 'diagnose and treat' peripheral lung cancer is on the horizon.

Mobile 3-dimensional (3D) C-arm system-assisted transbronchial biopsy and ablation for ground-glass opacity pulmonary nodules: a case report

Identification of pulmonary ground-glass opacity (GGO) lesions during bronchoscopic procedures remains challenging, as GGOs cannot be directly visualized under 2-dimensional (2D) fluoroscopy and are often difficult to detect by radial endobronchial ultrasound. Recently, a mobile 2D/3D C-arm fluoroscopy system was developed that provides both 2D fluoroscopy and mobile 3D imaging to assess and confirm the location of the lesions and ancillary bronchoscopic tools. However, previous studies focused mainly on experience of utilizing mobile 3D C-arm system for transbronchial biopsy of solid pulmonary nodules. Here, we evaluated the feasibility of mobile 3D imaging assisted transbronchial biopsy with and without ablation of two patients with GGO nodules. The first patient underwent biopsy only, and the second patient underwent biopsy in the right upper lobe lung nodule and ablation of a left upper lobe lung nodule in one session. Procedures in both patients were successfully performed, and no significant complications have been observed intra- or post-procedurally. Our case study highlights the potential value of the mobile 3D imaging system in accurate identification of the target lung lesion, confirmation of bronchoscopic tools within the lesion, and assessment of the target lesion and surrounding tissue following bronchoscopic ablation procedure. Furthermore, a “one-stop shop” bronchoscopy workflow combining both biopsy and ablation for one or more lung lesions in one session could be made possible by utilizing a hybrid mobile 2D/3D C-arm system in the bronchoscopy suite.