Convex Probe Endobronchial Ultrasound Research Articles

Endobronchial Ultrasound Image Simulation for Image-Guided Bronchoscopy.

Accurate disease diagnosis and staging are essential for patients suspected of having lung cancer. The state-of-the-art minimally invasive tools used by physicians to perform these operations are bronchoscopy, for navigating the lung airways, and endobronchial ultrasound (EBUS), for localizing suspect extraluminal cancer lesions. While new image-guided systems enable accurate bronchoscope navigation close to a lesion, no means exists for guiding the final EBUS localization of an extraluminal lesion. We propose an EBUS simulation method to assist with EBUS localization. The method draws on a patient's chest computed-tomography (CT) scan to model the ultrasound signal propagation through the tissue media. The method, which is suitable for simulating EBUS images for both radial-probe and convex-probe EBUS devices, entails three steps: 1) image preprocessing, which generates a 2D CT equivalent of the EBUS scan plane; 2) EBUS scan-line computation, which models ultrasound transmission to map the CT plane into a preliminary simulated EBUS image; and 3) image post-processing, which increases realism by introducing simulated EBUS imaging effects and artifacts. Results show that the method produces simulated EBUS images that strongly resemble images generated live by a real device and compares favorably to an existing ultrasound simulation method. It also produces images at a rate greater than real time (i.e., 53 frames/sec). We also demonstrate a successful integration of the method into an image-guided EBUS bronchoscopy system. The method is effective and practical for procedure planning/preview and follow-on live guidance of EBUS bronchoscopy.

Convex-probe Endobronchial Ultrasound: A Decade of Progress

Ever since the invention of the flexible bronchoscope, perhaps no other innovation in the field of interventional pulmonology has caused so much excitement the world over, as the convex probe endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA). While it took over a decade from 1992 to 2004 for the radial EBUS to evolve into the commercial convex probe EBUS scope, another exciting decade has gone by with the technology being thoroughly researched and appraised. The current evidence suggests that EBUS-TBNA can replace mediastinoscopy as the first investigation in the mediastinal staging of lung cancer. The use of EBUS-TBNA has been extended to several other areas including the diagnosis of undefined mediastinal lymphadenopathy, evaluation of intra-parenchymal lesions and others. In fact, EBUS-TBNA is the preferred modality for accessing mediastinal lesions in contact with the airways. The procedure not only has a high diagnostic efficiency (80%-90% for most indications) but is also safe compared to alternative options, such as image-guided fine needle aspiration and mediastinoscopy in the diagnosis of mediastinal lymphadenopathy. Apart from the traditional use of EBUS to perform TBNA, the last decade has seen the evolution of its transoesophageal use, development of novel EBUS-TBNA needles to obtain better histological specimens and a smaller EBUS scope. This review summarises the developments made in this field over the years since its inception.

Combination of 18F-FDG PET/CT and convex probe endobronchial ultrasound elastography for intrathoracic malignant and benign lymph nodes prediction.

BackgroundPositron emission tomography–computed tomography (PET/CT) and convex probe endobronchial ultrasound (CP-EBUS) elastography are important diagnostic methods in predicting intrathoracic lymph nodes (LNs) metastasis, but a joint analysis of the two examinations is still lacking. This study aimed to compare the diagnostic efficiency of the two methods and explore whether the combination can improve the diagnostic efficiency in differentiating intrathoracic benign LNs from malignant LNs.Materials and MethodsLNs examined by EBUS-guided transbronchial needle aspiration (EBUS-TBNA) and PET/CT from March 2018 to June 2019 in Shanghai Chest Hospital were retrospectively analyzed as the model group. Four PET/CT parameters, namely, maximal standardized uptake value mean standardized uptake value (SUVmean), SUVmean, metabolic tumor volume (MTV), and tumor lesion glycolysis (TLG); four quantitative elastography indicators (stiff area ratio, mean hue value, RGB, and mean gray value); and the elastography grading score of targeted LNs were analyzed. A prediction model was constructed subsequently and the dataset from July to November 2019 was used to validate the diagnostic capability of the model.ResultsA total of 154 LNs from 135 patients and 53 LNs from 47 patients were enrolled in the model and validation groups, respectively. Mean hue value and grading score were independent malignancy predictors of elastography, as well as SUVmax and TLG of PET/CT. In model and validation groups, the combination of PET/CT and elastography demonstrated sensitivity, specificity, positive and negative predictive values, and accuracy for malignant LNs diagnosis of 85.87%, 88.71%, 91.86%, 80.88%, and 87.01%, and 94.44%, 76.47%, 89.47%, 86.67%, and 88.68%, respectively. Moreover, elastography had better diagnostic accuracies than PET/CT in both model and validation groups (85.71% vs. 79.22%, 86.79% vs. 75.47%).ConclusionEBUS elastography demonstrated better efficiency than PET/CT and the combination of the two methods had the best diagnostic efficacy in differentiating intrathoracic benign from malignant LNs, which may be helpful for clinical application.

Multimodal Registration for Image-Guided EBUS Bronchoscopy.

The state-of-the-art procedure for examining the lymph nodes in a lung cancer patient involves using an endobronchial ultrasound (EBUS) bronchoscope. The EBUS bronchoscope integrates two modalities into one device: (1) videobronchoscopy, which gives video images of the airway walls; and (2) convex-probe EBUS, which gives 2D fan-shaped views of extraluminal structures situated outside the airways. During the procedure, the physician first employs videobronchoscopy to navigate the device through the airways. Next, upon reaching a given node’s approximate vicinity, the physician probes the airway walls using EBUS to localize the node. Due to the fact that lymph nodes lie beyond the airways, EBUS is essential for confirming a node’s location. Unfortunately, it is well-documented that EBUS is difficult to use. In addition, while new image-guided bronchoscopy systems provide effective guidance for videobronchoscopic navigation, they offer no assistance for guiding EBUS localization. We propose a method for registering a patient’s chest CT scan to live surgical EBUS views, thereby facilitating accurate image-guided EBUS bronchoscopy. The method entails an optimization process that registers CT-based virtual EBUS views to live EBUS probe views. Results using lung cancer patient data show that the method correctly registered 28/28 (100%) lymph nodes scanned by EBUS, with a mean registration time of 3.4 s. In addition, the mean position and direction errors of registered sites were 2.2 mm and 11.8, respectively. In addition, sensitivity studies show the method’s robustness to parameter variations. Lastly, we demonstrate the method’s use in an image-guided system designed for guiding both phases of EBUS bronchoscopy.

Preclinical evaluation of thin convex probe endobronchial ultrasound-guided transbronchial needle aspiration for intrapulmonary lesions.

BackgroundConventional flexible bronchoscopy has not achieved the high diagnostic yield for intrapulmonary lesions as seen with image-guided transthoracic biopsy. A thin convex probe endobronchial ultrasound bronchoscope (TCP-EBUS) with a 5.9-mm tip was designed to improve peripheral access over conventional EBUS bronchoscopes to facilitate real-time sampling of intrapulmonary lesions under ultrasound guidance.MethodsTCP-EBUS was inserted into the distal airways of ex-vivo human lungs to assess bronchial accessibility relative to clinically available bronchoscopes. The short- (≤1 h) and medium-term (≤10 d) safety of TCP-EBUS insertion and EBUS-guided transbronchial needle aspiration (TBNA) using a 25-gauge needle were evaluated physiologically and radiologically in live pigs. TCP-EBUS-guided TBNA feasibility was assessed in-vivo with pig intrapulmonary pseudo-tumors and ex-vivo with resected human lung cancer specimens.ResultsFor bronchial accessibility, TCP-EBUS demonstrated greater reach than the 6.6-mm convex probe endobronchial ultrasound (CP-EBUS) in all bronchi, as well as surpassed a 5.5-mm conventional bronchoscope in 63% (131/209) and a 4.8-mm conventional bronchoscope in 27% (57/209) of assessed bronchi. The median bronchial generation and the mean diameter of bronchi TCP-EBUS reached was 4 (range, 3–7) and 3.3±0.7 mm, respectively. No major complications related to TCP-EBUS-guided TBNA in distal airways were observed in the live pigs. Scattered mucosal erythema of the bronchial walls was observed immediately after TCP-EBUS insertion; this self-resolved by day 10. TCP-EBUS could successfully reach and visualize intrapulmonary targets via ultrasound, with no difficulty in needle deployment or sampling.ConclusionsTCP-EBUS has the potential to facilitate safe real-time transbronchial sampling of intrapulmonary lesions in the central and middle lung fields.

Big things come in small packages—Clinical use of endobronchial ultrasound

Endobronchial ultrasound (EBUS) revolutionized bronchoscopy. It first became available for clinical use in 1999 as a mechanical radial probe and was initially used to define airway wall anatomy, but was supplanted by convex probe EBUS bronchoscopes in 2002–now the preferred initial approach for evaluation of mediastinal pathology. Radial EBUS has since proven invaluable for evaluating the peripheral lung and aiding biopsy guidance despite the limitations in ultrasound (US) propagation through air filled structures. Centrally, airways pass through the mediastinum in direct contact with the esophagus, heart, great vessels, and lymph nodes, making the mediastinum amenable to direct US imaging. However, beyond the lung hila, the airways are largely surrounded by air, generally preventing production of usable US images by halting penetration and reverberation of sound waves. The tissue mass that makes up the terminal airway walls, however, does propagate ultrasound waves before encountering reflective air. The ratio of tissue to air varies according to anatomic location and physiologic/disease state; identifying patterns in the varying ratio of tissue to air within the lungs allows the ability to distinguish normal from abnormal lung. This presentation will describe the clinical use of EBUS in modern bronchoscopy.

Cryo-Biopsy versus 19G needle versus 22G needle with EBUS-TBNA endoscopy.

Introduction: We have been using cryo-biopsy for endobronchial lesions for lung cancer diagnosis and debulking. Cryo-biopsy is also known to be an excellent tool for diagnosis of lung interstitial disease. Recently cryo-biopsy with the 1.1mm probe was used for lymphnode biopsy.Patients and Methods: 311 patients participated with lymphadenopathy and at least one lung lesion. The following tools were used for diagnosis; 22G Mediglobe Sonotip, 22G Medigolbe, 21G Olympus, 19G Olympus and 1.1mm cryo probe ERBE CRYO 2 system (3 seconds froze). A PENTAX Convex-probe EBUS was used for biopsy guidance.Results: Cell-blocks slices had a higher number in the 19G needle group (19G> Cryo Probe>22G Mediglobe Sonotip >21G Olympus >22G Mediglobe).Conclusion: Cryo biopsy of the lymphnodes is safe with the 1.1mm cryo probe. Further studies are needed in order to evaluate new probes and the technique specifications.

An evolving role for endobronchial ultrasonography in the intensive care unit.

Endobronchial ultrasound (EBUS) bronchoscopy is an established minimally-invasive modality for visualization, characterization, and guidance of sampling of paratracheal and parabronchial structures and tissues. In the intensive care unit (ICU), rapidly obtaining an accurate diagnosis is paramount to the management of critically ill patients. In some instances, diagnosing and confirming terminal illness in a critically ill patient provides needed closure for patients and their loved ones. Currently available data on feasibility, safety, and yield of EBUS bronchoscopy in critically ill patients is based on single center experiences. These data suggest that in select ICU patients convex and radial probe-EBUS bronchoscopy can serve as useful tools in the evaluation of mediastinal lymphadenopathy, central airway obstruction, pulmonary embolism, and peripheral lung lesions. Barriers to the use of EBUS bronchoscopy in the ICU include: (I) requirement for dedicated equipment, prolonged procedure time, and bronchoscopy team expertise that may not be available; (II) applicability to a limited number of patients and conditions in the ICU; and (III) technical difficulty related to the relatively large outer diameter of the convex probe-EBUS bronchoscope and an increased risk for adverse cardiopulmonary consequences due to intermittent obstruction of the artificial airway. While the prospects for EBUS bronchoscopy in critically ill patients appear promising, judicious patient selection in combination with bronchoscopy team expertise are of utmost importance when considering performance of EBUS bronchoscopy in the ICU setting.

Endobronchial Ultrasound Improves the Diagnosis of the Tracheobronchial Invasion of Advanced Esophageal Cancer.

Accurate diagnosis of the tracheobronchial invasion of advanced esophageal cancer is essential to select appropriate treatment and improve prognosis; however, it is difficult using the conventional modalities. This study aimed to clarify the diagnostic usefulness of convex probe endobronchial ultrasound (CP-EBUS) for the diagnosis of the tracheobronchial invasion of advanced esophageal cancer. We conducted a cadaveric study to clarify the changes in ultrasonic and histopathologic findings in the esophageal tumor and tracheal invasion models. Additionally, we examined CP-EBUS for patients with advanced thoracic esophageal cancer in whom tracheobronchial invasion was suspected on contrast-enhanced computed tomography (CE-CT) scan. We retrospectivity evaluated the diagnosis of CP-EBUS, comparing the pathological findings and treatment outcomes. Cadaveric esophageal tumor and tracheal invasion models showed the disappearance of the third layer observed with CP-EBUS and histologically proven interruption of the adventitia. This indicated that the third layer corresponded with the tracheal adventitia. We examined 40 patients with advanced thoracic esophageal cancer in whom tracheobronchial invasion was suspected. The precise diagnosis was pathologically confirmed in 9 of 14 patients diagnosed with cT3 who underwent radical surgery. 20 of 26 cases diagnosed with cT4b received definitive chemoradiotherapy, and 4 cases received salvage surgery and pathologically confirmed precise diagnosis. CP-EBUS is extremely useful for diagnosing the tracheobronchial invasion of advanced esophageal cancer. It could be an effective modality for determining treatment strategies in cases with a marginal surgical indication.

Recent advances in convex probe endobronchial ultrasound: a narrative review.

Convex probe endobronchial ultrasound (CP-EBUS) has been widely used in the lymph node staging and restaging of lung tumors and the diagnosis of mediastinal diseases. Recent years have seen continuous progress in this technology. For diagnosis, elastography technology can preliminarily distinguish between benign and malignant lesions, so that reduce the number of punctures. CP-EBUS can also be used as an endoscopic ultrasound (EUS) to guide needle aspirations of liver lesions, retroperitoneal lymph nodes and left adrenal gland (LAG) lesions sometimes. Some advances help diagnosing more accurately and effectively, such as the intranodal forceps biopsy (IFB), the new type of 22G needle, the rapid on-site evaluation (ROSE) and the cancer gene methylation, etc. In addition, special advances are being made in diagnosis using artificial intelligence (AI). For treatment, CP-EBUS has yielded novel research results when applied to transbronchial needle injection (TBNI) and radioactive seed implantation in clinical cases, and blocking of the cardiac plexus in animal studies. The next-generation CP-EBUS is also ready for use in the clinic and the technology will be improving continuously. Through this review, we hope to educate clinicians on the latest uses of CP-EBUS and open up further research ideas for readers interested in this technology.

Deep learning with convex probe endobronchial ultrasound multimodal imaging: A validated tool for automated intrathoracic lymph nodes diagnosis.

Background and Objectives:Along with the rapid improvement of imaging technology, convex probe endobronchial ultrasound (CP-EBUS) sonographic features play an increasingly important role in the diagnosis of intrathoracic lymph nodes (LNs). Conventional qualitative and quantitative methods for EBUS multimodal imaging are time-consuming and rely heavily on the experience of endoscopists. With the development of deep-learning (DL) models, there is great promise in the diagnostic field of medical imaging.Materials and Methods:We developed DL models to retrospectively analyze CP-EBUS images of 294 LNs from 267 patients collected between July 2018 and May 2019. The DL models were trained on 245 LNs to differentiate benign and malignant LNs using both unimodal and multimodal CP-EBUS images and independently evaluated on the remaining 49 LNs to validate their diagnostic efficiency. The human comparator group consisting of three experts and three trainees reviewed the same test set as the DL models.Results:The multimodal DL framework achieves an accuracy of 88.57% (95% confidence interval [CI] [86.91%–90.24%]) and area under the curve (AUC) of 0.9547 (95% CI [0.9451–0.9643]) using the three modes of CP-EBUS imaging in comparison to the accuracy of 80.82% (95% CI [77.42%–84.21%]) and AUC of 0.8696 (95% CI [0.8369–0.9023]) by experts. Statistical comparison of their average receiver operating curves shows a statistically significant difference (P < 0.001). Moreover, the multimodal DL framework is more consistent than experts (kappa values 0.7605 vs. 0.5800).Conclusions:The DL models based on CP-EBUS imaging demonstrated an accurate automated tool for diagnosis of the intrathoracic LNs with higher diagnostic efficiency and consistency compared with experts.

Endobronchial Ultrasound Transbronchial Needle Aspiration for the Diagnosis of Paratracheal and Peribronchial Central Parenchymal Lesions.

Obtaining qualitative, sufficient material for the diagnosis of malignancies in cases with normal endoscopic findings in patients with suspected lung cancer and hilar and mediastinal lymphadenopathy is challenging. Endobronchial ultrasound (EBUS) was used to control a transbronchial needle biopsy (ТBNA) for the first time in our country. From 2015 to 2018, TBNA with a convex probe EBUS was performed on 57 patients [41 men, 16 women, mean age 56.10 (range 37-77 years)] with mediastinal lesions found on CT scan. We used the Hitachi Aloka - ProSound Alpha 7 and BF-UC180F (Olympus) 21G and 22G needles Ultrasound System. In 22 of the cases, we performed a biopsy of hilum lesions (9 on the left and 13 on the right), in 13 - of subcarinal lesions, and in 4 - of lesions located on the right paratracheal lymphatic chain. EBUS-TBNA confirmed lung cancer in 48 patients (84.2%). In 33 of them, it was non-small cell lung cancer: spinocellular in 13 cases and adenocarcinoma in 17 cases; three cases were without accurate verification. Small cell lung cancer was found in 15 cases. In two cases, the biopsies were negative for tumor (3.5%), and in seven - non-specific inflammatory process (12.3%). This study confirms the high diagnostic success rate of EBUS-TBNA reported in similar studies developed on a daily routine basis without adhering to a specific protocol. EBUS-TBNA is an interventional procedure with high sensitivity in diagnosing hilar and mediastinal lesions in negative conventional bronchoscopy and thus is useful in patients with paratracheal and peribronchial lesions. The results could be improved with training and experience.

SAFETY OF LARYNGEAL MASK AIRWAY USE WITH GENERAL ANASTHESIA DURING INTERVENTIONAL BRONCHOSCOPIC PROCEDURES

SESSION TITLE: Procedures Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: General anesthesia can be used with more advanced bronchoscopy procedures to help with patient tolerance and outcomes for procedures that may be more prolonged . The use of endotracheal tubes prevents complete evaluation of the trachea and upper airway for some procedures, while a laryngeal mask airway (LMA) can help provide a protected airway for deeper sedation and anesthesia and improve upper airway visualization. The purpose of our study is to evaluate the safety, efficacy profile, and outcomes of using LMA for upper airway management during interventional bronchoscopy procedures under general anesthesia. METHODS: We performed a retrospective, single center chart review, analyzing data from 295 patients undergoing bronchoscopic procedures between August 2017-October 2018. Of the 290 patients who had general anesthesia for their procedures, 117 patients (41%) had an LMA placed during their procedures. Almost all those procedures were convex probe EBUS bronchoscopies. RESULTS: Our patient population was 46% male; 48% white, 52 % were African-American and 1% were Hispanic . The median age was 68 years-old and average BMI mean was 28. Many patients have multiple medical comorbidities, with ASA -2 in 21 % , ASA-3 in 67% , and ASA-4 in 12% of the patients. Procedure times averaged 71 minutes in LMA group, and 81 minutes in non-LMA group. Seven (6 %) patients had their LMA changed to ETT to complete their procedures due to inadequate ventilation. There were no cardiac complications (acute coronary syndrome, decompensated heart failure) following anesthesia. One patient had hypoxic respiratory failure that required hospital admission for 1 day. One patient had post procedure nausea. Transient intra-procedural hypotension did happen in 13 patients (15%) that resolved by the end of the procedure with use of IVF fluid and small dose of IV vasopressors. CONCLUSIONS: In general, there were no difficulties with airway maintenance during the procedures. All of the procedures were able to be completed without interruption or delay and recovered without significant incident. LMA is a safe device to use during general anesthesia with interventional bronchoscopies procedures even with advanced ASA scores. CLINICAL IMPLICATIONS: During Interventional bronchoscopic procedures ( especially convex probe EBUS), LMA uses provide safe and feasible method to manage the upper airway during general anesthesia. DISCLOSURES: No relevant relationships by Ammar Alqaid, source=Web Response No relevant relationships by Rishi Arora, source=Web Response No relevant relationships by David Chambers, source=Web Response No relevant relationships by Allen Elster, source=Web Response No relevant relationships by Paul Fisher, source=Web Response Site Investigator for EMPROVE relationship with Olympus-Spiration Please note: $1001 - $5000 Added 06/15/2020 by Robert Holladay, source=Web Response, value=Grant/Research Support Site Investigator for DAS 181 relationship with Ansun pharmaceutical Please note: $1001 - $5000 Added 06/15/2020 by Robert Holladay, source=Web Response, value=Grant/Research Support No relevant relationships by Aditya Sithamraju, source=Web Response

Risk/caution of vitamin D insufficiency for quarantined athletes returning to play after COVID-19

Flexible bronchoscopy plays a major role in the diagnosis and staging of lung cancer. One of the most important advances in this field is the development of endobronchial ultrasound (EBUS),...

Mediastinal ve hiler lenfadenopatilerde endobronşiyal ultrason eşliğinde kullanılan power Doppler modunun benign ve malign lenf nodu ayırımına katkısı

Aim: The aim of this study was to investigate the contribution of power Doppler mode used in the differentiation of malignant and benign lymph nodes in patients with mediastinal and hilar lymphadenopathies undergoing diagnostic fine needle aspiration under the guidance of convex probe endoscopic ultrasound (EBUS).Material and Methods: Medical files of patients who underwent EBUS between March 2018 and February 2019 were retrospectively analyzed. A total of 143 lymph nodes of 85 patients were included in the study. The demographic characteristics of the patients with a definite diagnosis and EBUS radiological and sonographic characteristics of the sampled lymph nodes were recorded. As a result of the evaluation of mediastinal lymph nodes with EBUS, the sensitivity, specificity, negative and positive predictive values were calculated for power Doppler mode in the detection of malignant lymph nodes.Results: Of a total of 85 patients, 62 (73%) were males and 23 (27%) were females with a mean age of 62±10.4 (range, 37 to 80) years. In the vascular pattern evaluation, 87 (60.8%) lymph nodes were negative and 56 (39.2%) were positive for malignancy. Comparing final diagnoses and vascular pattern analysis results revealed a statistically significant difference between benign and malignant lymph nodes in favor of power Doppler mode under the guidance of EBUS (p &amp;lt;0.01).Conclusion: Convex probe EBUS can identify the first lymph node to be sampled based on sonographic characteristics of lymph nodes and allow simultaneous imaging and transbronchial fine needle aspiration procedures. Therefore, it may shorten the procedural time and reduce the amount of anesthesia to be used.

Convex probe endobronchial ultrasound: historical, contemporary, and cutting-edge applications.

The use of convex-probe endobronchial ultrasound (CP-EBUS) has revolutionized bronchoscopy. It has provided the option of a relatively safe, minimally invasive approach for the assessment of various intrathoracic diseases. In current practice, its most dramatic impact has been on the diagnosing and staging of lung cancer. It has served as an invaluable tool that has replaced mediastinoscopy in a variety of clinical scenarios. Many pulmonologists and thoracic surgeons consider CP-EBUS the most significant milestone in bronchoscopy after the development of the flexible bronchoscope itself. In this review, we summarize the historical aspects, current indications, technical approach, and future direction of CP-EBUS.

EUS-B-FNA FOR LEFT ADRENAL LESIONS IN NON-SMALL CELL LUNG CANCER PATIENTS: REPORT OF CASES AND LITERATURE REVIEW

The left adrenal gland (LAG) is a common metastatic site in patients with non-small-cell lung cancer. In practice, staging mainly relies on radiologic studies and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Recently, a new technique using convex probe-endobronchial ultrasound (CP-EBUS) scope through the esophagus (EUS-B) has been introduced. A complete mediastinal staging and a reach for upper-abdominal structures in a single session naturally attract attention. However, scientific data are not sufficient to clearly judge the role of this technique in the cytological diagnosis of left adrenal lesions. Therefore, we present cases in which our patients have undergone EUS-B for LAG lesions to increase the data in the literature with regard to accessibility, diagnostic performance, and rate of complications.

ES07.03 Radial Endosonography

Flexible bronchoscopy, with its attendant procedures, is a valuable tool for diagnosis and staging of patients with suspected lung cancer. The development of endobronchial ultrasound (EBUS) has extended the view of the bronchoscopist beyond the bronchial wall. Two types of EBUS exist. The curved linear (convex) probe EBUS and the radial probe EBUS. The convex ultrasound transducer is located at the tip of a flexible bronchoscope (linear scanning EBUS) and allows real-time sampling. This technique is mainly used for mediastinal nodal staging and assessment of centrally located lung tumours when lung cancer is known or suspected. The radial EBUS probe houses a rotating ultrasound transducer at the distal end which produces a high-resolution radial (360˚) ultrasound image of the airway wall and surrounding structures. This probe is inserted through the biopsy channel of a standard bronchoscope. In a lung cancer setting, this technique is used for evaluation of the depth of tumour invasion in the central airways enabling differentiation between early and invasive lung cancer and detection of peripheral pulmonary lesions (PPLs). Radial EBUS does not permit sampling in real-time such that sequential sampling with separate equipment is necessary. The current focus of this abstract is the role of radial EBUS for PPLs. With the increased use of chest CT-scans, the frequency of incidentally found PPLs has increased as well. Guidelines advise to evaluate and manage individuals with pulmonary nodules by estimating the probability of malignancy. The goal is to diagnose a malignancy promptly for timely treatment and to avoid invasive procedures and surgery in patients with benign lesions. Approaches to establish a tissue diagnosis include imaging-guided transthoracic and bronchoscopic sampling techniques. The sensitivity of traditional flexible bronchoscopy – with or without fluoroscopic guidance – for peripheral lesions in patients suspected of having lung cancer is suboptimal and is affected most by the size of the lesion (<2cm 34%; >2cm 63%).(1) For PPLs, the sensitivity of transthoracic needle aspiration (TTNA) is greater than that of bronchoscopy. In this setting, TTNA has an approximately 90% chance of providing confirmation of a diagnosis. However, CT-guided percutaneous TTNA has a considerable risk of pneumothorax.(1) This has led to the development of new modalities as radial EBUS, virtual bronchoscopy, electromagnetic navigation bronchoscopy and ultrathin bronchoscopes. In 2002, radial EBUS was first used to guide transbronchial lung biopsy (TBLB).(2) Numerous papers has been published since, reporting varying diagnostic performances of radial EBUS. Three systematic reviews and meta-analyses report a sensitivity of radial EBUS for diagnosis of peripheral lesions of 70% to 73%. Although there is considerable heterogeneity in lesion size, prevalence of malignancy, variable use of additional image guiding technology and reference standard in included studies.(3-5) The diagnostic yield of radial EBUS is significantly higher for lesion > 2 cm in size, malignant in nature and those associated with a bronchus sign on CT scan.(3-5) The diagnostic yield is also higher when the radial EBUS probe is in the center of the lesion opposed to being adjacent to it.(3) The diagnostic yield of radial EBUS does not exceed CT-guided percutaneous needle biopsy / aspiration. The major advantage of radial EBUS over a transthoracic approach is its safety profile (overall pneumothorax rate of just 1.0%)(4) and the ability to combine with staging procedures. In conclusion, to diagnose PPLs (not visible by bronchoscopy) radial EBUS is a safe and has a reasonably high diagnostic yield. Main limitations of the technique include operator dependence and the need for sequential sampling as radial EBUS does not allow real-time sampling. 1. Rivera MP, Mehta AC, Wahidi MM. Establishing the diagnosis of lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest. 2013;143(5 Suppl):e142S-e65S. 2. Herth FJ, Ernst A, Becker HD. Endobronchial ultrasound-guided transbronchial lung biopsy in solitary pulmonary nodules and peripheral lesions. The European respiratory journal. 2002;20(4):972- 3. Ali MS, Trick W, Mba BI, Mohananey D, Sethi J, Musani AI. Radial endobronchial ultrasound for the diagnosis of peripheral pulmonary lesions: A systematic review and meta-analysis. Respirology (Carlton, Vic). 2017;22(3):443-53. 4. Steinfort DP, Khor YH, Manser RL, Irving LB. Radial probe endobronchial ultrasound for the diagnosis of peripheral lung cancer: systematic review and meta-analysis. The European respiratory journal. 2011;37(4):902-10. 5. Wang Memoli JS, Nietert PJ, Silvestri GA. Meta-analysis of guided bronchoscopy for the evaluation of the pulmonary nodule. Chest. 2012;142(2):385-93. Radial endosonography, diagnosis, lung cancer

Role of Convex Probe Endobronchial Ultrasound in the Diagnosis and Treatment of Nonmalignant Diseases.

Here we present a comprehensive review of the literature concerning the utility of convex probe endobronchial ultrasound (CP-EBUS) in the diagnosis and treatment of nonmalignant conditions and discuss the associated complications. CP-EBUS has been conventionally used for the staging of lung cancer and sampling of mediastinal and hilar nodes. However, its application is not limited to malignant conditions, and it is gaining acceptance as a diagnostic modality of choice for nonmalignant conditions such as tuberculosis, sarcoidosis, pulmonary embolism, thyroid lesions, and cysts. Moreover, its therapeutic value allows for extended applications such as mediastinal and thyroid cyst drainage, fiducial marker placement for radiation therapy, and transbronchial needle injection. The noninvasiveness, low complication rate, high diagnostic yield, and satisfactory sensitivity and specificity values are the main attributes that lend credence to the use of CP-EBUS as a standalone primary diagnostic and therapeutic tool in pulmonary medicine in the foreseeable future.

Transbronchial evaluation of peripheral pulmonary lesions using ultrasonic spectrum analysis in lung cancer patients.

Analysis of the endobronchial ultrasound (EBUS) radiofrequency spectrum has been used for convex-probe EBUS technology. Quantitative imaging analysis is also warranted for guided bronchoscopy using radial-probe EBUS (RP-EBUS) targeting peripheral pulmonary lesions (PPL). This study aimed to determine the feasibility of radiofrequency spectrum analysis for distinguishing malignant and benign PPL during diagnostic bronchoscopy. Raw RP-EBUS images with radiofrequency data, including backscatter signals, were prospectively recorded. The ultrasonic spectral parameters, such as intercept, midband-fit and slope within the region of interest, were retrospectively computed by linear regression analysis and compared with the final diagnosis. A total of 71 PPL, including 45 malignant and 26 benign lesions, were analysed. Malignant PPL showed a significantly lower intercept (P < 0.0001), lower midband-fit (P < 0.0001) and higher slope (P = 0.014) than benign PPL. Analyses of the area under the curve of receiver operating characteristic plots demonstrated that the intercept showed the best diagnostic performance among three parameters (0.87, 0.77 and 0.69 for intercept, midband-fit and slope, respectively). The sensitivity, specificity, accuracy, positive likelihood and negative likelihood were 75.6%, 96.2%, 83.1%, 19.6 and 0.25 for the intercept; 88.9%, 57.7%, 77.5%, 2.1 and 0.19 for the midband-fit; and 68.9%, 73.1%, 70.4%, 2.6 and 0.43 for the slope. Spectrum analysis of EBUS radiofrequency can be used as a novel non-invasive predictor of malignant or benign PPL. Analysis of the 'intercept' of the targeted lesion may provide useful supporting data for real-time sampling from PPL during diagnostic bronchoscopy.