Endobronchial Ultrasound Plus Fluoroscopy Versus Fluoroscopy-Guided Bronchoscopy: A Comparison of Diagnostic Yields in Peripheral Pulmonary Lesions

Inheritance and innovation of the diagnosis of peripheral pulmonary lesions

As the leading cause of cancer-related deaths worldwide, early detection and diagnosis are crucial to reduce the mortality of lung cancer. To date, the diagnosis of the peripheral pulmonary lesions (PPLs) remains a major unmet clinical need. The urgency of diagnosing PPLs has driven a series of development of the advanced bronchoscopy-guided techniques in the past decades, such as radial probe-endobronchial ultrasonography (RP-EBUS), virtual bronchoscopy navigation (VBN), electromagnetic navigation bronchoscopy (ENB), bronchoscopic transparenchymal nodule access (BTPNA), and robotic-assisted bronchoscopy. However, these techniques also have their own limitations. In this review, we would like to introduce the development of diagnostic techniques for PPLs, with a special focus on biopsy approaches and advanced guided bronchoscopy techniques by discussing their advantages, limitations, and future prospects.

Effectiveness of Endobronchial Ultrasound-Guided Transbronchial Biopsy Combined With Tissue Culture for the Diagnosis of Sputum Smear-Negative Pulmonary Tuberculosis

Background

Microorganisms of tuberculosis (TB) are frequently difficult to identify from the airway specimen; therefore, lung biopsy for further histologic and microbiologic study is required. Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of pulmonary malignancy, but is rarely in the TB population. The purpose of this study was to verify the effectiveness and safety of EBUS-TBB with histologic study and tissue culture in the diagnosis of sputum smear-negative pulmonary TB.

Methods

Patients who underwent EBUS-TBB with histologic study and TB tissue culture for clinically suspected, but sputum smear-negative pulmonary TB from January 2016 to December 2018, were included. The accuracy of each diagnostic modality was calculated, respectively. Factors that might influence the positive rate of TB culture (washing fluid and tissue specimen) were also evaluated.

Results

One hundred sixty-one patients who underwent EBUS-TBB for clinically suspected, but sputum smear-negative pulmonary TB, were enrolled, and 43 of them were finally diagnosed as having pulmonary TB. The sensitivity of washing fluid (a combination of smear, culture, and polymerase chain reaction for TB) and tissue specimen (a combination of pathology and tissue culture) via EBUS-TBB for TB diagnosis were 48.8 and 55.8%, respectively. The sensitivity for TB diagnosis would be elevated to 67.4% when both washing fluid and tissue specimens are used. The positive TB culture rate would not statistically increase with a combination of tissue specimens and washing fluid. Univariate analysis revealed that TB microorganisms would be more easily cultivated when lesions had an abscess or cavity on the computed tomography (CT) image (presence vs. absence; 62.5 vs. 26.3%, p = 0.022), heterogeneous echogenicity on the EBUS finding (heterogeneous vs. homogeneous; 93.3 vs. 21.4%, p = 0.001), or a necrotic pattern via histologic study (presence vs. absence; 70.6 vs. 30.8%, p = 0.013). Heterogeneous echogenicity in the EBUS finding was the independent predictor according to the results of multivariate analysis. None of our patients encountered major adverse events or received further intensive care after EBUS-TBB.

Conclusion

Endobronchial ultrasound-guided transbronchial biopsy is safe and effective for use in diagnosing sputum smear-negative pulmonary TB. EBUS echoic feature is also a predictor of the positive TB culture rate in pulmonary TB. However, tissue culture via EBUS-TBB has little effect in improving the positive TB culture rate.

Cone-Beam Computed Tomography-Derived Augmented Fluoroscopy Improves the Diagnostic Yield of Endobronchial Ultrasound-Guided Transbronchial Biopsy for Peripheral Pulmonary Lesions

Background: Endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB) is used for the diagnosis of peripheral pulmonary lesions (PPLs), but the diagnostic yield is not adequate. Cone-beam computed tomography-derived augmented fluoroscopy (CBCT-AF) can be utilized to assess the location of PPLs and biopsy devices, and has the potential to improve the diagnostic accuracy of bronchoscopic techniques. The purpose of this study was to verify the contribution of CBCT-AF to EBUS-TBB. Methods: Patients who underwent EBUS-TBB for diagnosis of PPLs were enrolled. The navigation success rate and diagnostic yield were used to evaluate the effectiveness of CBCT-AF in EBUS-TBB. Results: In this study, 236 patients who underwent EBUS-TBB for PPL diagnosis were enrolled. One hundred fifteen patients were in CBCT-AF group and 121 were in non-AF group. The navigation success rate was significantly higher in the CBCT-AF group (96.5% vs. 86.8%, p = 0.006). The diagnostic yield was even better in the CBCT-AF group when the target lesion was small in size (68.8% vs. 0%, p = 0.026 for lesions ≤10 mm and 77.5% vs. 46.4%, p = 0.016 for lesions 10–20 mm, respectively). The diagnostic yield of the two study groups became similar when the procedures with a failure of navigation were excluded. The procedure-related complication rate was similar between the two study groups. Conclusion: CBCT-AF is safe, and effectively enhances the navigation success rate, thereby increasing the diagnostic yield of EBUS-TBB for PPLs.

Effectiveness of convolutional neural networks in the interpretation of pulmonary cytologic images in endobronchial ultrasound procedures

BACKGROUND

Rapid on-site cytologic evaluation (ROSE) helps to improve the diagnostic accuracy in endobronchial ultrasound (EBUS) procedures. However, cytologists are seldom available to perform ROSE in many institutions. Recent studies have investigated the application of deep learning in cytologic image analysis. As such, the present study analyzed lung cytologic images obtained by EBUS procedures, and employed deep-learning methods to distinguish between benign and malignant cells and to semantically segment malignant cells.

METHODS

Ninety-seven patients who underwent 104 EBUS procedures were enrolled. Four hundred and ninety-nine lung cytologic images obtained via ROSE, including 425 malignant and 74 benign, and most malignant were lung adenocarcinoma (64.3%). All the images were used to train a residual network model with 101 layers (ResNet101), with suitable hyperparameters selected to classify benign and malignant lung cytologic images. An HRNet model was also employed to mark the area of malignant cells. Automatic patch-cropping was adopted to facilitate dataset preparation.

RESULTS

Malignant cells were successfully classified by ResNet101 with 98.8% classification accuracy, 98.8% sensitivity, and 98.8% specificity in patch-based classification; 95.5% classification accuracy in image-based classification; and 92.9% classification accuracy in patient-based classification. Malignant cell area was successfully marked by HRNet with a mean intersection over union of 89.2%. The automatic cropping method enabled the system to complete diagnosis within 1 s.

CONCLUSIONS

This is the first study to combine lung cytologic image deep-learning classification with semantic segmentation. The model was optimized for high accuracy and the automatic cropping facilitates the clinical application of our model. The success in both lung cytologic images classification and semantic segmentation on our dataset shows a promising result for clinical application in the future.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Rapid on-site cytologic evaluation by pulmonologist improved diagnostic accuracy of endobronchial ultrasound-guided transbronchial biopsy

BACKGROUND/PURPOSE

Rapid on-site cytologic evaluation (ROSE) has been shown to improve the diagnostic accuracy of endobronchial ultrasound-guided transbronchial biopsy (EBUS-TBB). However, ROSE by a cytopathologist or cytotechnologist is not always available during the procedure. The purposes of this study were to verify that a pulmonologist, after receiving training in cytology, could accurately assess an EBUS-TBB specimen on-site, and to evaluate the contribution of ROSE to EBUS-TBB.

METHODS

A retrospective chart review of patients who underwent EBUS-TBB for diagnosis of peripheral pulmonary lesions (PPLs) from January 2014 to June 2017 was performed. PPLs without a malignant diagnosis were excluded. The ROSE result determined by a pulmonologist was compared to the formal imprint cytologic report and pathologic report. The diagnostic accuracy of EBUS-TBB was also compared between those with and without ROSE.

RESULTS

Two hundred ninety-three patients who underwent 336 EBUS-TBB procedures for PPL diagnosis and were found to have proven malignancy were enrolled. Eighty-six procedures were performed with ROSE. With the formal imprint cytologic diagnosis as the standard, ROSE had 96.9% sensitivity, 68.2% specificity, 89.9% positive predictive value (PPV), 88.2% negative predictive value (NPV), and 89.5% diagnostic accuracy. With the formal pathologic result as the standard, ROSE had 88.2% sensitivity, 80% specificity, 97.1% PPV, 47.1% NPV, and 87.2% diagnostic accuracy, respectively. The diagnostic accuracy was significantly higher when ROSE was performed during EBUS-TBB (88.4% vs 68.0%, P < 0.001).

CONCLUSION

A trained pulmonologist can interpret adequately cytologic smears on-site and effectively improve the accuracy of EBUS-TBB in the diagnosis of PPLs.

Factors Related to the Diagnostic Yield of Flexible Bronchoscopy without Guidance in Bronchoscopically Invisible Peripheral Lung Lesions

BACKGROUND

We aimed to analyze the factors predicting the diagnostic performance of flexible bronchoscopy without guidance in peripheral lung lesions that are endoscopically invisible.

METHODS

This was a retrospective study conducted in St. Paul's Hospital, The Catholic University of Korea, between January 2007 and March 2013. We included all patients who received bronchoscopy during this period. The analyzed variables were age, sex, the etiology of the lesion, lesion size, distance from the pleura, and presence of the bronchus sign. We used multiple logistic regression analysis to identify the significant independent factors associated with diagnostic yield.

RESULTS

We included 151 patients in this study. The overall diagnostic yield was 58.3%. The sensitivity was 43.2% for malignant disease and 78.1% for benign disease. The benign lung lesions (p<0.001), lesion size (p=0.015), presence of the exposed type of bronchus sign (p<0.001), and presence of cavitary lung lesions (p=0.005) were factors influencing the yield of flexible bronchoscopy by univariate analysis. In a multivariate logistic regression analysis, the exposed type of bronchus sign and benign lung lesions were independent predicting factors (odds ratio [OR]: 27.95; 95% confidence interval [CI], 7.56-103.32; p<0.001 and OR, 4.91; 95% CI, 1.76-13.72; p=0.002).

CONCLUSION

The presence of the exposed type of bronchus sign and benign lung lesions are determining factors of the diagnostic yield in flexible bronchoscopy in evaluating peripheral lesions that are not endoscopically visible.

Endobronchial ultrasound plus fluoroscopy-guided biopsy compared to fluoroscopy-guided transbronchial biopsy for obtaining samples of peripheral pulmonary lesions: A systematic review and meta-analysis

BACKGROUND:

We report a meta-analysis of recent studies comparing the diagnostic yields of endobronchial ultrasonography plus fluoroscopically-guided transbronchial biopsy (EBUS + TBB) with that of conventional fluoroscopically-guided TBB for peripheral pulmonary lesions (PPLs).

METHODS:

We searched Medline, the Cochrane Library, PubMed, and Google Scholar through 31 March 2013 using the keywords: lung neoplasm, pulmonary lesions, diagnosis, endobronchial ultrasound, fluoroscopy, and fluoroscopic.

RESULTS:

Four studies were included in the study with a total of 461 patients, 222 in the EBUS + TBB group and 239 in the TBB only group. The meta-analysis revealed that the group with EBUS + TBB was more favored in terms of positive diagnostic yield than the group diagnosed with only conventional TBB (odds ratio [OR] = 2.211, 95% confidence interval [CI] = 1.422–3.438, P < 0.001). Subgroup analysis based on lesion size found that smaller PPLs had higher accuracy (OR = 4.502, 95% CI = 2.002–10.126, P < 0.001) than PPLs of large size (OR = 1.849, 95% CI = 1.033–3.311, P = 0.039).

CONCLUSION:

Obtaining TBB samples for histopathological diagnosis is enhanced by the addition of EBUS to conventional fluoroscopic guidance; this is, especially important for patients with small peripheral lung lesions who benefit greatly from early diagnosis.

Shifted focus of bronchoalveolar lavage in patients with suspected thoracic malignancy: an analysis of 224 patients

BACKGROUND

Bronchoscopies are extensively adopted for diagnosing and staging thoracic malignancies, but studies are missing as how to keep the process streamlined and more efficient. To evaluate current role of bronchoalveolar lavage (BAL) for cancer and possible infection diagnosis when practicing comprehensive bronchoscopy for patients suspected with thoracic malignancy, and provide foundation for possible practice modification.

METHODS

We retrospectively analyzed a prospectively kept database of immunocompetent patients undergoing bronchoscopy for suspected non-hematologic malignancies. Clinical, radiographic data, bronchoscopic sampling techniques and diagnostic results were recorded. Initially undiagnostic patients were followed up for 2 years for a definitive diagnosis.

RESULTS

Of 224 patients included, 179 (79.9%) were confirmed with active thoracic malignancies. BAL diagnostic yield of cancer based on different radiographic characters of target lesion are as follow: isolated lymphadenopathies 0%, central lesions 45.5%, peripheral masses (diameter ≥3 cm) 21.4%, peripheral large nodules (2≤ diameter <3 cm) 15.8%, and peripheral small nodules (diameter <2 cm) 7.1%, while composite bronchoscopy achieved diagnostic yield of 93.3%, 95.5%, 91.7%, 76.9%, and 66.7% in corresponding lesion types. No cancer was diagnosed solely by BAL-cytology. Proportions of patients with positive BAL culture did not differ significantly between patients with and without pre-test suspicion for infections (P=0.199). In multivariable analysis, infections were associated with age ≥75 (OR 3.0; 95% CI: 1.29-7.06), chronic obstructive pulmonary disease (COPD) (OR 2.7; 95% CI: 1.14-6.26) and diabetes mellitus (DM) (OR 4.5; 95% CI: 1.90-10.44).

CONCLUSIONS

Omitting BAL cytology in settings of comprehensive bronchoscopy may not compromise cancer diagnosis. For patients primarily suspected with thoracic malignancy, performing BAL culture only based on clinical suspicion could miss important infectious etiology.

Comparison of diagnostic performances among bronchoscopic sampling techniques in the diagnosis of peripheral pulmonary lesions

BACKGROUND

There are many sampling techniques dedicated to radial endobronchial ultrasound (R-EBUS) guided flexible bronchoscopy (FB). However, data regarding the diagnostic performances among bronchoscopic sampling techniques is limited. This study was conducted to compare the diagnostic yields among bronchoscopic sampling techniques in the diagnosis of peripheral pulmonary lesions (PPLs).

METHODS

A prospective study was conducted on 112 patients who were diagnosed with PPLs and underwent R-EBUS-guided FB between Oct 2012 and Sep 2014. Sampling techniques-including transbronchial biopsy (TBB), brushing cell block, brushing smear, rinsed fluid of brushing, and bronchoalveolar lavage (BAL)-were evaluated for the diagnosis.

RESULTS

The mean diameter of the PPLs was 23.5±9.5 mm. The final diagnoses included 76 malignancies and 36 benign lesions. The overall diagnostic yield of R-EBUS-guided bronchoscopy was 80.4%; TBB gave the highest yield among the 112 specimens: 70.5%, 34.8%, 62.5%, 50.0% and 42.0% for TBB, brushing cell block, brushing smear, rinsed brushing fluid, and BAL fluid (BALF), respectively (P<0.001). TBB provided high diagnostic yield irrespective of the size and etiology of the PPLs. The combination of TBB and brushing smear achieved the maximum diagnostic yield. Of 31 infectious PPLs, BALF culture gave additional microbiological information in 20 cases.

CONCLUSIONS

TBB provided the highest diagnostic yield; however, to achieve the highest diagnostic performance, TBB, brushing smear and BAL techniques should be performed together.

Endobronchial ultrasound for the diagnosis of peripheral pulmonary lesions. A controlled study with fluoroscopy

INTRODUCTION

Fluoroscopy-guided bronchoscopy is usually performed for the diagnosis of peripheral pulmonary lesions (PPL), but the diagnostic yield varies widely among studies. Endobronchial ultrasound (EBUS) can increase the diagnostic yield of bronchoscopic diagnosis of PPL.

OBJECTIVE

To compare the diagnostic yield of fluoroscopy-guided bronchoscopy and EBUS with fluoroscopy-guided bronchoscopy in the study of PPL.

METHODS

All patients who underwent bronchoscopy to study PPL from January 2009 to December 2012 were prospectively included. 145 consecutive patients were randomly distributed in two groups: EBUS and fluoroscopy (50 patients, 71.3 ± 8.2 years) or fluoroscopy alone (95 patients, 68 ± 10.5 years). The mean diameter of the lesions was 41.97 ± 19.22 mm. Cytological brushing and transbronchial biopsies were obtained. All procedures were performed under fluoroscopic guidance with intravenous conscious sedation. EBUS was performed using an endoscopic ultrasound system equipped with a 20-MHz radial miniprobe introduced via a guide-sheath. Bronchoscopist, cytologist, study protocol, techniques and tools were the same throughout the whole study.

RESULTS

129 (89%) patients had malignant disease. A diagnosis with bronchoscopy was established in 105 (72.4%) patients. EBUS plus fluoroscopy obtained a diagnostic yield in 78% of patients and fluoroscopy alone in 69.5% (non-significant). In contrast, for lesions smaller than 30 mm, EBUS plus fluoroscopy guidance provided significantly greater diagnostic performance than fluoroscopy alone (90 vs. 52%; P=.05).

CONCLUSIONS

Bronchoscopy under EBUS plus fluoroscopy guidance is a technique that has become useful for the diagnostic of LPPs, especially those smaller than 30 mm in diameter.

Newer modalities in the work-up of peripheral pulmonary nodules

Technological advances in recent years have translated into the availability of newer modalities to establish the cause of peripheral pulmonary nodules (PPN). Even though the verdict is still out on the ideal diagnostic modality, there is no doubt that the bronchoscope is becoming a popular tool in the armamentarium of physicians who deal with PPN. This article focuses on newer bronchoscopic modalities being studied for the work-up of PPN. The authors also summarize the value of established diagnostic modalities to provide a balanced perspective.