Roy Joseph Cho

Lung cancer remains the leading cause of cancer-related mortality worldwide despite advances in screening, navigational bronchoscopy, and systemic therapies. Diagnostic and therapeutic limitations persist, including uncertainty regarding intraprocedural tissue adequacy during biopsy sampling and constraints of existing ablative modalities for tumors located near critical thoracic structures. This review examines two emerging technologies: Full-Field Optical Coherence Tomography-based Dynamic Cell Imaging (DCI) and monopolar biphasic Pulsed Electric Field (PEF) ablation as complementary emerging technologies that may address these gaps. The Van Gogh™ Microscopy System (CellTivity Scientific, Inc.) utilizes DCI to enable real-time visualization of cellular metabolic activity without tissue destruction, providing functional information regarding tissue viability and microstructural morphology. The Aliya^® PEF ablation system (Galvanize Therapeutics, Inc.) delivers biphasic high-voltage electrical pulses that induce non-thermal tumor cell death while preserving extracellular matrix architecture, potentially allowing treatment near sensitive thoracic structures such as airways, vasculature, and pleura. Early preclinical studies and initial clinical experience suggest that DCI can facilitate rapid intraprocedural assessment of biopsy adequacy, while PEF ablation may provide reproducible focal tumor destruction with a favorable safety profile near critical structures. Although the current evidence base remains limited to early-phase studies and feasibility trials, the convergence of real-time biologic tissue assessment with structurally preserving ablation technologies introduces the possibility of integrating diagnostic confirmation and local therapy within a single procedural workflow. This review summarizes the mechanistic rationale, emerging evidence, and potential clinical applications of these technologies and proposes a conceptual “See and Strike” framework within these two emerging technologies. The methodological limitations, workflow considerations, and future research directions required to validate this approach are also discussed. Prospective multicenter trials and long-term oncologic outcomes will be necessary before widespread clinical adoption.

Airway stenting allows restoration of airway patency however associated airway injury and mucostasis can incur significant comorbidity and mortality. We aim to compare a coated stent vs non-coated stent in both degree of airway injury and mucostasis.

Medical ultrasound has emerged as an indispensable tool within interventional pulmonology, revolutionizing diagnostic and procedural practices through its non-invasive nature and real-time visualization capabilities. By harnessing the principles of sound waves and employing a variety of transducer types, ultrasound facilitates enhanced accuracy and safety in procedures such as transthoracic needle aspiration and pleural effusion drainage, consequently leading to improved patient outcomes. Understanding the fundamentals of ultrasound physics is paramount for clinicians, as it forms the basis for interpreting imaging results and optimizing interventions. Thoracic ultrasound plays a pivotal role in diagnosing conditions like pleural effusions and pneumothorax, while also optimizing procedures such as thoracentesis and biopsy by providing precise guidance. Advanced ultrasound techniques, including endobronchial ultrasound, has transformed the evaluation and biopsy of lymph nodes, bolstered by innovative features like elastography, which contribute to increased procedural efficacy and patient safety. Peripheral ultrasound techniques, notably radial endobronchial ultrasound (rEBUS), have become essential for assessing pulmonary nodules and evaluating airway structures, offering clinicians valuable insights into disease localization and severity. Neck ultrasound serves as a crucial tool in guiding supraclavicular lymph node biopsy and percutaneous dilatational tracheostomy procedures, ensuring safe placement and minimizing associated complications. Ultrasound technology is suited for further advancement through the integration of artificial intelligence, miniaturization, and the development of portable devices. These advancements hold the promise of not only improving diagnostic accuracy but also enhancing the accessibility of ultrasound imaging in diverse healthcare settings, ultimately expanding its utility and impact on patient care. Additionally, the integration of enhanced techniques such as contrast-enhanced ultrasound and 3D imaging is anticipated to revolutionize personalized medicine by providing clinicians with a more comprehensive understanding of anatomical structures and pathological processes. The transformative potential of medical ultrasound in interventional pulmonology extends beyond mere technological advancements; it represents a paradigm shift in healthcare delivery, empowering clinicians with unprecedented capabilities to diagnose and treat pulmonary conditions with precision and efficacy. By leveraging the latest innovations in ultrasound technology, clinicians can navigate complex anatomical structures with confidence, leading to more informed decision-making and ultimately improving patient outcomes. Moreover, the portability and versatility of modern ultrasound devices enable their deployment in various clinical settings, from traditional hospital environments to remote or resource-limited areas, thereby bridging gaps in healthcare access and equity.

During the COVID-19 pandemic, ventilator shortages necessitated the development of new, low-cost ventilator designs. The fundamental requirements of a ventilator include precise gas delivery, rapid adjustments, durability, and user-friendliness, often achieved through solenoid valves. However, few solenoid-valve assisted low-cost ventilator (LCV) designs have been published, and gas exchange evaluation during LCV testing is lacking. This study describes the development and performance evaluation of a solenoid-valve assisted low-cost ventilator (SV-LCV) in vitro and in vivo, focusing on gas exchange and respiratory mechanics. The SV-LCV, a fully open ventilator device, was developed with comprehensive hardware and design documentation, utilizing solenoid valves for gas delivery regulation. Lung simulator testing calibrated tidal volumes at specified inspiratory and expiratory times, followed by in vivo testing in a porcine model to compare SV-LCV performance with a conventional ventilator. The SV-LCV closely matched the control ventilator’s respiratory profile and gas exchange across all test cycles. Lung simulator testing revealed direct effects of compliance and resistance changes on peak pressures and tidal volumes, with no significant changes in respiratory rate. In vivo testing demonstrated comparable gas exchange parameters between SV-LCV and conventional ventilator across all cycles. Specifically, in cycle 1, the SV-LCV showed arterial blood gas (ABG) results of pH 7.54, PCO2 34.5 mmHg, and PO2 91.7 mmHg, compared to the control ventilator’s ABG of pH 7.53, PCO2 37.1 mmHg, and PO2 134 mmHg. Cycle 2 exhibited ABG results of pH 7.53, PCO2 33.6 mmHg, and PO2 84.3 mmHg for SV-LCV, and pH 7.5, PCO2 34.2 mmHg, and PO2 93.5 mmHg for the control ventilator. Similarly, cycle 3 showed ABG results of pH 7.53, PCO2 32.1 mmHg, and PO2 127 mmHg for SV-LCV, and pH 7.5, PCO2 35.5 mmHg, and PO2 91.3 mmHg for the control ventilator. The SV-LCV provides similar gas exchange and respiratory mechanic profiles compared to a conventional ventilator. With a streamlined design and performance akin to commercially available ventilators, the SV-LCV presents a viable, readily available, and reliable short-term solution for overcoming ventilator supply shortages during crises.

Background and aim: Endobronchial biopsy (EBBX) has been reported to increase diagnostic yield for pulmonary sarcoidosis. The purpose of this study is to investigate the diagnostic yield for EBBX following endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA). Methods: We identified a cohort of patients in the University of Minnesota Sarcoidosis Registry who had EBBx and EBUS-TBNA as part of workup for abnormal chest imaging. Data regarding demographics, biopsy approach and technique were recorded. Results: Our cohort included 37 patients (53.24 +/- 9.5, Male, 22 +/- 0.57; 3.8% were African American). In these patients who had EBBX, EBUS-TBNA was performed in 100% of patients and TBBX was performed in 2 patients (5%). EBBX was positive in 9 patients (24%) and EBUS-TBNA was positive in 34 patients (92%). TBBX was diagnostic in one of two patients. EBBX was the only diagnostic tissue in 3 of the 37 patients (8%). Conclusion: The diagnostic yield of EBBX is lower than previously reported, with only 8% of EBBXs demonstrating granulomatous inflammation. However, instrumentation used for obtaining EBBX as well as the presence of visible lesions does influence the diagnostic yield. Studies with adequate power are needed before implementing changes in clinical practice. When performed alongside EBUS-TBNA, EBBX did not significantly add to the diagnostic yield in sarcoidosis unless visible lesions were observed.

Background: Stent encrustation with debris and mucostasis is a significant cause of airway injury and comorbidity, leading to ~25% of stent exchanges (1–3). Previous work from our group has shown that the experimental coating can reduce mucous adhesion in bench testing and demonstrated a signal for reducing airway injury and mucostasis in a feasibility study. Objectives: The aim of this study is to continue our inquiry in a randomized, single-blinded multi-animal trial to investigate the degree of airway injury and mucostasis using silicone stents with and without this specialized coating. Methods: We modified commercially available silicone stents with a hydrophilic polymer from Toray Industries. We conducted an in vivo survival study in 6 mainstem airways (3 coated and 3 uncoated) of 3 pigs to compare the degree of airway injury and mucostasis between coated versus noncoated stented airways. Both stents were randomized to either left or right mainstem bronchus. The pathologist was blinded to the stent type. Results: We implanted a total of six 14×15 mm silicone stents (1 per mainstem bronchi) into 3 pigs. All animals survived to termination at 4 weeks. All stents were intact; however, 1 uncoated stent migrated out. On average, all the coated stents demonstrated reduced pathology and tissue injury scores (75 vs. 68.3, respectively). The average total dried mucous weight was slightly higher in the coated stents (0.07 g vs. 0.05 g; respectively). Conclusion: Coated stents had lower airway injury compared with uncoated stents in this study. Of all the stents, 1 uncoated stent migrated out and was not included in the dried mucous weight totals. This could explain the slightly higher mucous weight in the coated stents. Nevertheless, this current study demonstrates promising results in lowering airway injury in stents incorporated with the hydrophilic coating, and future studies, including a larger number of subjects, would be needed to corroborate our findings.

Background: Electromagnetic navigation bronchoscopy (ENB) and robotic-assisted bronchoscopy (RAB) systems are used for pulmonary lesion sampling, and utilize a pre-procedural CT scan where an airway, or “bronchus sign”, is used to map a pathway to the target lesion. However, up to 40% of pre-procedural CT’s lack a “bronchus sign” partially due to surrounding emphysema or limitation in CT resolution. Recognizing that the branches of the pulmonary artery, lymphatics, and airways are often present together as the bronchovascular bundle, we postulate that a branch of the pulmonary artery (“artery sign”) could be used for pathway mapping during navigation bronchoscopy when a “bronchus sign” is absent. Herein we describe the navigation success and safety of using the “artery sign” to create a pathway for pulmonary lesion sampling. Methods: We reviewed data on consecutive cases in which the “artery sign” was used for pre-procedural planning for conventional ENB (superDimension™, Medtronic) and RAB (Monarch™, Johnson & Johnson). Patients who underwent these procedures from July 2020 until July 2021 at the University of Minnesota Medical Center and from June 2018 until December 2019 at the University of Chicago Medical Center were included in this analysis (IRB #19-0011 for the University of Chicago and IRB #00013135 for the University of Minnesota). The primary outcome was navigation success, defined as successfully maneuvering the bronchoscope to the target lesion based on feedback from the navigation system. Secondary outcomes included navigation success based on radial EBUS imaging, pneumothorax, and bleeding rates. Results: A total of 30 patients were enrolled in this analysis. The median diameter of the lesions was 17 mm. The median distance of the lesion from the pleura was 5 mm. Eleven lesions were solid, 15 were pure ground glass, and 4 were mixed. All cases were planned successfully using the “artery sign” on either the superDimension™ ENB (n = 15) or the Monarch™ RAB (n = 15). Navigation to the target was successful for 29 lesions (96.7%) based on feedback from the navigation system (virtual target). Radial EBUS image was acquired in 27 cases (90%) [eccentric view in 13 (43.33%) and concentric view in 14 patients (46.66%)], while in 3 cases (10%) no r-EBUS view was obtained. Pneumothorax occurred in one case (3%). Significant airway bleeding was reported in one case (3%). Conclusions: We describe the concept of using the “artery sign” as an alternative for planning EMN and RAB procedures when “bronchus sign” is absent. The navigation success based on virtual target or r-EBUS imaging is high and safety of sampling of such lesions compares favorably with prior reports. Prospective studies are needed to assess the impact of the “artery sign” on diagnostic yield.

Purpose: Balloon-expandable stents are commonly used for the treatment of tracheobronchial strictures. We routinely perform targeted overdilation of these stents 1– 2mm on initial deployment to prevent stent migration or allow foreshortening to target airway caliber; however, specific data on the effect of targeted overdilation is unknown. Patients and Methods: We used three iCAST stents (6× 22mm, 7× 22mm, and 10× 38mm) to perform the study. We had two sets of each size to average our results. Targeted overdilation was accomplished with Merit Elation balloons. Results: The 6 × 22 and 7 × 22 stent OD increased from 6 to 11.4mm and 7 to 11.6mm. The 10 × 38 stent demonstrated minimal OD change with overdilation (OD change of 10.4 to 12.2mm). All stents demonstrated significant foreshortening with overdilation (20.2 to 5.65mm, 19.4 to 6mm, and 30.9 to 10.2mm for 6 × 22, 7 × 22, and 10 × 38, respectively). The breakpoint was seen at near twice the stated stent OD (13.5mm, 15mm, and 15mm with 6 × 22, 7 × 22 and 10 × 38, respectively). Conclusion: We have demonstrated that iCAST stents can increase their OD with subsequent foreshortening during targeted overdilation. This data can help facilitate decisions when selecting a particular iCAST stent for a specific airway application. Additionally, we have highlighted that balloon inflation diameter does not correspond to the actual stent OD during deployment. We believe that this data offers practical information for end-users of this stent type and additional data will be needed to corroborate our findings.

Background: There is a paucity of real-time imaging modalities available for the bronchoscopic biopsy of peripheral lung nodules. We aim to demonstrate the feasibility of the O-arm imaging system to guide real-time biopsies of peripheral lung nodules during electromagnetic navigation bronchoscopy. Methods: A retrospective review was performed at 2 academic medical centers utilizing O-arm guidance. Results: The average nodule size was 2.1×2.0 cm and were mostly solid (66%) with a positive bronchus sign (83%). O-arm imaging confirmed tool-in-lesion in all cases. The diagnostic yield was 33%. Four cases were nondiagnostic of the 6 cases performed. In these cases, necrotic tissue was the most common (75%) and showed resolution following subsequent imaging. The average 3-dimensional (3D) spin time was 23.5 seconds. The average number of 3D spins performed per case was 4.33. The average effective dose per 3D spin was 3.73 mSv. Conclusion: We have demonstrated the O-arm’s feasibility with electromagnetic navigation bronchoscopy for peripheral lung nodules. The O-arm was able to confirm tool-in-lesion in all cases which added confidence to the biopsy. Four high-resolution 3D spins per case may limit the total computed tomography effective dose. We also noted that both metal and radiation scatter were minimal when appropriate radiation safety standards were met. Although additional experience and data will be required to verify the O-arm approach for routine use, our initial experience is promising.