Cone Beam CT Guidance Improves Transbronchial Lung Cryobiopsy Safety

Transbronchial lung cryobiopsy for peripheral pulmonary lesions. A narrative review

An increasing number of peripheral pulmonary lesions (PPLs) requiring tissue verification to establish a definite diagnosis for further individualized management are detected due to the growing adoption of lung cancer screening by chest computed tomography (CT), especially low-dose CT. However, the morphological diagnosis of PPLs remains challenging. Transbronchial lung cryobiopsy (TBLC) that can retrieve larger specimens with more preserved cellular architecture and fewer crush artifacts in comparison with conventional transbronchial forceps biopsy (TBFB), as an emerging technology for diagnosing PPLs, has been demonstrated to have the potential to resolve the clinical dilemma pertaining to currently available sampling devices (e.g., forceps, needle and brush) and become a diagnostic cornerstone for PPLs. Of note, with the introduction of the 1.1 mm cryoprobe that will be more compatible with advanced bronchoscopic navigation techniques, such as radial endobronchial ultrasound (r-EBUS), virtual bronchoscopic navigation (VBN) and electromagnetic navigation bronchoscopy (ENB), the use of TBLC is expected to gain more popularity in the diagnosis of PPLs. While much remains for exploration using the TBLC technique for diagnosing PPLs, it can be envisaged that the emergence of additional studies with larger data accrual will hopefully add to the body of evidence in this field.

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.

Low bleeding rates following transbronchial lung cryobiopsy in unclassifiable interstitial lung disease

BACKGROUND AND OBJECTIVE

Bronchoscopic transbronchial lung cryobiopsy (TBLC) is a guideline-endorsed alternative to surgical lung biopsy for tissue diagnosis in unclassifiable interstitial lung disease (ILD). The reported incidence of post-procedural bleeding has varied widely. We aimed to characterize the incidence, severity and risk factors for clinically significant bleeding following TBLC using an expert-consensus airway bleeding scale, in addition to other complications and diagnostic yield.

METHODS

A retrospective cohort study of consecutive adult outpatients with unclassifiable ILD who underwent TBLC following multidisciplinary discussion at a single centre in the UK between July 2016 and December 2021. TBLC was performed under general anaesthesia with fluoroscopic guidance and a prophylactic endobronchial balloon.

RESULTS

One hundred twenty-six patients underwent TBLC (68.3% male; mean age 62.7 years; FVC 86.2%; DLCO 54.5%). Significant bleeding requiring balloon blocker reinflation for >20 min, admission to ICU, packed red blood cell transfusion, bronchial artery embolization, resuscitation or procedural abandonment, occurred in 10 cases (7.9%). Significant bleeding was associated with traction bronchiectasis on HRCT (OR 7.1, CI 1.1-59.1, p = 0.042), a TBLC histological pattern of UIP (OR 4.0, CI 1.1-14, p = 0.046) and the presence of medium-large vessels on histology (OR 37.3, CI 6.5-212, p < 0.001). BMI ≥30 (p = 0.017) and traction bronchiectasis on HRCT (p = 0.025) were significant multivariate predictors of longer total bleeding time (p = 0.017). Pneumothorax occurred in nine cases (7.1%) and the 30-day mortality was 0%. Diagnostic yield was 80.6%.

CONCLUSION

TBLC has an acceptable safety profile in experienced hands. Radiological traction bronchiectasis and obesity increase the risk of significant bleeding following TBLC.

The accuracy of electromagnetic navigation bronchoscopy compared to fluoroscopy in navigation of transbronchial lung cryobiopsy in patients with interstitial lung disease

BACKGROUND

Safely implementing transbronchial lung cryobiopsy (TBLC) in patients with interstitial lung disease (ILD) requires accurate navigation. Traditional fluoroscopy falls short in reducing the risk of post-procedure pneumothorax. The potential of electromagnetic navigation bronchoscopy (ENB) as a more precise navigation method warrants further exploration.

METHODS

A prospective cohort study was conducted on ILD patients undergoing TBLC. Patients were assigned either fluoroscopy or ENB for cryoprobe positioning. Navigation accuracy was evaluated using cone beam computed tomography (CBCT) images as the standard. Safety and diagnostic yield were also observed.

RESULTS

Seventeen patients underwent TBLC, with 10 guided by fluoroscopy and seven by ENB. Fluoroscopy-guided cryoprobe navigation required more adjustments [9/15 (60%) v.s. 1/9 (11%), p = 0.018] for subsequent TBLC compared to ENB, as confirmed by CBCT images. Clinical characteristics, post-procedure complications, and biopsy specimen size showed no significant differences between the groups. Fourteen patients obtained a pathological diagnosis, and 15 received a multidisciplinary discussion (MDD) diagnosis. In the fluoroscopy group, three patients failed to obtain a pathological diagnosis, and two failed to obtain an MDD diagnosis.

CONCLUSIONS

ENB demonstrates significantly superior accuracy in TBLC navigation compared to traditional fluoroscopy when CBCT images are used as a reference. Further studies are necessary to determine the value of ENB in TBLC navigation for ILD patients.

Transbronchial Lung Cryobiopsy Performed with Cone Beam Computed Tomography Guidance Versus Fluoroscopy: A Retrospective Cohort Review

PURPOSE

Determining the cause of interstitial lung disease (ILD) remains challenging. While surgical lung biopsy remains the gold standard approach, risks associated with it may be prohibitive. Transbronchial lung cryobiopsy (TBLC) is a minimally invasive alternative with an improved safety profile and acceptable diagnostic accuracy. We retrospectively assessed whether the use of Cone Beam computed tomography guidance for TBLC (TBLC-CBCT) improves safety and diagnostic yield compared to performing TBLC with fluoroscopic guidance (TBLC-F).

METHODS

A retrospective cohort review of 120 patients presenting for evaluation of newly diagnosed ILD was performed. Demographic data, pulmonary function test values, chest imaging pattern, procedural information, and final multidisciplinary discussion (MDD) diagnosis were recorded.

RESULTS

62 patients underwent TBLC-F and 58 underwent TBLC-CBCT. Patients undergoing TBLC-CBCT were older (67.86 ± 10.97 vs 61.45 ± 12.77 years, p = 0.004) and had a higher forced vital capacity percent predicted (73.80 ± 17.32% vs 66.00 ± 17.45%, p = 0.03) compared to the TBLC-F group. The average probe-to-pleura distance was 5.1 ± 2.3 mm in the TBLC-CBCT group with 4.0 ± 0.3 CBCT spins performed. Pneumothorax occurred more often in the TBLC-F group (n = 6, 9.7%) compared to the TBLC-CBCT group (n = 1, 1.7%, p = 0.06). Grade 2 bleeding only occurred in the TBLC-F group (n = 4, 6.5%). A final MDD diagnosis was obtained in 89% (n = 57) of TBLC-F patients and 95% (n = 57) of TBLC-CBCT patients.

CONCLUSIONS

TBLC-CBCT appears to be safer compared to TBLC-F with both approaches facilitating an MDD diagnosis. Further studies from multiple institutions randomizing patients to each modality are needed to confirm these findings.

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.

Real-world utility of a genomic classifier in establishing a diagnosis of newly identified interstitial lung disease

BACKGROUND

Diagnosing interstitial lung disease (ILD) remains challenging. Guidelines recommend utilizing a multidisciplinary discussion (MDD) to review clinical and radiographic data and if diagnostic uncertainty persists, then to obtain histopathology. Surgical lung biopsy and transbronchial lung cryobiopsy (TBLC) are acceptable methods, but risks of complications may be prohibitive. The Envisia genomic classifier (EGC) represents another option to determine a molecular usual interstitial pneumonia (UIP) signature to facilitate an ILD diagnosis at MDD with high sensitivity and specificity. We evaluated the concordance between TBLC and EGC at MDD and the safety of this procedure.

METHODS

Demographic data, pulmonary function values, chest imaging pattern, procedural information, and MDD diagnosis were recorded. Concordance was defined as agreement between the molecular EGC results and histopathology from TBLC in the context of the patient's High Resolution CT pattern.

RESULTS

49 patients were enrolled. Imaging demonstrated a probable (n = 14) or indeterminate (n = 7) UIP pattern in 43% and an alternative pattern in 57% (n = 28). EGC results were positive for UIP in 37% (n = 18) and negative in 63% (n = 31). MDD diagnosis was obtained in 94% (n = 46) with fibrotic hypersensitivity pneumonitis (n = 17, 35%) and IPF (n = 13, 27%) most common. The concordance between EGC and TBLC at MDD was 76% (37/49) with discordant results seen in 24% (12/49) of patients.

CONCLUSIONS

There appears to be reasonable concordance between EGC and TBLC results at MDD. Efforts clarifying the contributions of these tools to an ILD diagnosis may help identify specific patient populations that may benefit from a tailored diagnostic approach.

Evaluation of large airway specimens obtained by transbronchial lung cryobiopsy in diffuse parenchymal lung diseases

Background

The difference in diagnostic yield between surgical lung biopsy and transbronchial lung cryobiopsy (TBLC) in diffuse parenchymal lung diseases (DPLD) has been reported to be due to differences in the rate of interpathologist agreement, specimen size, and specimen adequacy. In TBLC, the specimens containing large airway components are generally believed as inadequate specimens for histological evaluation, but the detailed characteristics of TBLC specimens including the large airway and the impact on histological diagnostic rates of DPLD have not been investigated.

Methods

We retrospectively reviewed the specimen characteristics of patients with DPLD who underwent TBLC.

Results

Between February 2018 and January 2020, 74 patients and 177 specimens were included. There were 85 (48.0%) large airway specimens (LAS) that contained bronchial gland or bronchial cartilage. The ideal specimen ratio was significantly lower in the LAS-positive group than that in the LAS-negative group (5.8% vs. 45.6%), and the proportion of bronchioles, alveoli, and perilobular area were similarly lower in the LAS-positive group. The presence of traction bronchiectasis and diaphragm overlap sign on high-resolution computed tomography (HRCT) were also significantly higher in the LAS-positive group than those in the LAS-negative group. We observed a statistically significant trend in histological diagnostic yield (40.7% in LAS positive group; 60.8% in LAS positive and negative group; 91.6% in LAS negative group) (Cochran-Armitage trend test).

Conclusion

LAS is a specimen often collected in TBLC and contains a low percentage of bronchioles, alveoli, and perilobular area. Since the histological diagnostic yield tends to be higher in cases that do not contain LAS, it may be important to determine the biopsy site that reduces the frequency of LAS collection by referring to the HRCT findings in TBLC.

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.

Applications of cryobiopsy in airway, pleural, and parenchymal disease

INTRODUCTION

:Cryobiopsy is a novel diagnostic technique for thoracic diseases which has been extensively investigated over the past 20 years. It was originally proposed for the diagnosis of endobronchial lesions and diffuse parenchymal lung disease due to limitations of conventional sampling techniques including small size and presence of artifacts.

AREAS COVERED

:We will review recent evidence related to the expanding use of cryobiopsy in thoracic diseases. To identify references, the MEDLINE database was searched from database inception until May 2022 for case series, cohort studies, randomized controlled trials, systematic reviews and meta-analyses related to cryobiopsy.

EXPERT OPINION

Cryobiopsy has expanding applications in the field of thoracic diseases. Evidence to support transbronchial cryobiopsy as an alternative to surgical lung biopsy is increasing and was recently endorsed as a conditional recommendation by the latest American Thoracic Society guideline update for Idiopathic Pulmonary Fibrosis. Developments in technology and technique, in particular the availability of a 1.1 mm flexible cryoprobe, have extended applications to pulmonary diseases, including diagnosis of interstitial lung diseases, peripheral pulmonary lesions, and lung transplant rejection.

Transbronchial Lung Cryobiopsy for Diffuse Parenchymal Lung Disease

Transbronchial lung cryobiopsy (TBLC) offers a minimally invasive option for the diagnosis of diffuse parenchymal lung diseases, of which interstitial lung diseases comprise the most common diagnoses. It has a high diagnostic yield with prognostic and therapeutic implications. TBLC has a favorable safety profile compared with surgical lung biopsy, but associated complications include pneumothorax and bleeding. However, TBLC techniques remain variable. Here we review the latest techniques described to maximize diagnostic yield and mitigate complications of TBLC as well as how this modality has been incorporated into guidelines.

Transbronchial Lung Cryobiopsy is Safe and Effective for Diagnosing Acutely Ill Hospitalized Patients with New Diffuse Parenchymal Lung Disease

INTRODUCTION

Transbronchial lung cryobiopsy (TBLC) is an accepted alternative to surgical lung biopsy (SLB) for diagnosing diffuse parenchymal lung disease (DPLD) that is less invasive and results in comparable diagnostic yields. Performing lung biopsies on hospitalized patients, however, has increased risk due to the patient's underlying disease severity. Data evaluating the safety and efficacy of TBLC in hospitalized patients are limited. We present a comparison of TBLC for hospitalized and outpatients and provide the safety and diagnostic yields in these populations.

METHODS

Demographic data, pulmonary function values, chest imaging pattern, procedural information, and diagnosis were recorded from enrolled patients. Complications from the procedure were the primary outcomes and diagnostic yield was the secondary outcome.

RESULTS

77 patients (n = 22 hospitalized vs n = 55 outpatient) underwent TBLC during the study period. Comparing adverse events between hospitalized and outpatients revealed no statistically significant differences in pneumothorax (9%, n = 2 vs 5%,n = 3), tube thoracostomy placement (5%, n = 1 vs 2%, n = 1), grade 2 bleeding (9%, n = 2 vs 0%, n = 0), escalation in level of care (5%, n = 1 vs 0%, n = 0), 30-day mortality (9%, n = 2 vs 2%, n = 1), and 60-day mortality (9%, n = 2 vs 4%, n = 2) (p > 0.05 for all). No deaths were attributed to the procedure. 95% of cases received a multidisciplinary conference diagnosis (hospitalized 100%, n = 22 vs outpatients 93%, n = 51, p = 0.32).

CONCLUSION

Our experience supports that TBLC may be a safe and effective modality for acutely ill-hospitalized patients with DPLD. Further efforts to enhance procedural safety and to determine the impact of an expedited tissue diagnosis on patient outcomes are needed.

Robotic bronchoscopy and future directions of interventional pulmonology

PURPOSE OF REVIEW

To describe the emerging field of robotic bronchoscopy within advanced diagnostic bronchoscopy. We review the literature available for these two novel platforms to highlight their differences and discuss the impact on future directions.

RECENT FINDINGS

There are two distinct technologies both known as robotic bronchoscopy. The Monarch robotic-assisted bronchoscopy is based on electromagnetic guidance whereas the Ion robotic-assisted bronchoscopy is founded on shape sensing technology. Although there is ongoing work to explore the capabilities of these systems, studies have shown that both are safe modalities. Furthermore, both hold promise to improve diagnostic yield and may eventually pave the way for therapeutic bronchoscopic ablation in the future.

SUMMARY

Although both platforms fall under the umbrella term of robotic-assisted bronchoscopy, the Monarch and Ion systems are quite unique in their technology. Thus far, both have demonstrated safety, and early data shows promising results for improved diagnostic yield compared to previously advanced bronchoscopy modalities, especially when combined with advanced confirmatory imaging. Future directions may include bronchoscopic ablation of peripheral lesions given the stability and reach of these platforms.