Single-Cell Characterization of Pulmonary Nodules Implicates Suppression of Immunosurveillance across Early Stages of Lung Adenocarcinoma.

A greater understanding of molecular, cellular, and immunological changes during the early stages of lung adenocarcinoma development could improve diagnostic and therapeutic approaches in patients with pulmonary nodules at risk for lung cancer. To elucidate the immunopathogenesis of early lung tumorigenesis, we evaluated surgically resected pulmonary nodules representing the spectrum of early lung adenocarcinoma as well as associated normal lung tissues using single-cell RNA sequencing and validated the results by flow cytometry and multiplex immunofluorescence (MIF). Single-cell transcriptomics revealed a significant decrease in gene expression associated with cytolytic activities of tumor-infiltrating natural killer and natural killer T cells. This was accompanied by a reduction in effector T cells and an increase of CD4+ regulatory T cells (Treg) in subsolid nodules. An independent set of resected pulmonary nodules consisting of both adenocarcinomas and associated premalignant lesions corroborated the early increment of Tregs in premalignant lesions compared with the associated normal lung tissues by MIF. Gene expression analysis indicated that cancer-associated alveolar type 2 cells and fibroblasts may contribute to the deregulation of the extracellular matrix, potentially affecting immune infiltration in subsolid nodules through ligand-receptor interactions. These findings suggest that there is a suppression of immune surveillance across the spectrum of early-stage lung adenocarcinoma. SIGNIFICANCE: Analysis of a spectrum of subsolid pulmonary nodules by single-cell RNA sequencing provides insights into the immune regulation and cell-cell interactions in the tumor microenvironment during early lung tumor development.

A Novel Simulated Training Platform and Study of Performance Among Different Levels of Learners in Flexible Cystoscopy.

INTRODUCTION: The aims of this study were to test a novel simulation platform suitable for flexible cystoscopy using a standard scope, to assess the platform's proposed use as a training tool for flexible cystoscopy, and to assess the user experience through surveyed response. METHODS: Thirty-one urologists (11 novices, 20 experts) were evaluated using a novel light-based bladder model and standard flexible cystoscope. Time to complete full inspection of the simulated bladder was measured, and the scope trajectory was recorded. Participants also completed a survey of the training platform. RESULTS: Thirty participants completed a simulated inspection of a portable bladder model with a mean ± SD time for 153.1 ± 76.1 seconds. One participant failed to complete. Novice urologists (defined as those having completed less than 50 flexible cystoscopies in clinic) had a mean ± SD time of 176.9 ± 95.8 seconds, whereas with experts, this decreased to 139.3 ± 60.7 seconds. Dynamic trajectory maps identified "blind spots" within each user's cystoscopy performance. In a poststudy follow-up, 27 participants considered the tool valuable or extremely valuable for training, whereas 19 participants considered that the tool either very well or excellently replicated the clinical setting. All participants ranked the tool as very good or excellent for overall quality of training. DISCUSSION: Advances in electronic technology make portable low-cost models a potential low-cost alternative to endourology training platforms. In providing a quantifiable measure of user performance, the tool may shorten the learning curve in flexible cystoscopy and, potentially, reduce clinical errors and provide quantifiable measures for further clinical training.

Automated Catheter Navigation With Electromagnetic Image Guidance.

This paper describes a novel method of controlling an endoscopic catheter by using an automated catheter tensioning system with the objective of providing clinicians with improved manipulation capabilities within the patient. Catheters are used in many clinical procedures to provide access to the cardiopulmonary system. Control of such catheters is performed manually by the clinicians using a handle, typically actuating a single or opposing set of pull wires. Such catheters are generally actuated in a single plane, requiring the clinician to rotate the catheter handle to navigate the system. The automation system described here allows closed-loop control of a custom bronchial catheter in tandem with an electromagnetic tracking of the catheter tip and image guidance by using a 3D Slicer. An electromechanical drive train applies tension to four pull wires to steer the catheter tip, with the applied force constantly monitored through force sensing load cells. The applied tension is controlled through a PC connected joystick. An electromagnetic sensor embedded in the catheter tip enables constant real-time position tracking, whereas a working channel provides a route for endoscopic instruments. The system is demonstrated and tested in both a breathing lung model and a preclinical animal study. Navigation to predefined targets in the subject's airways by using the joystick while using virtual image guidance and electromagnetic tracking was demonstrated. Average targeting times were 29 and 10 s, respectively, for the breathing lung and live animal studies. This paper presents the first reported remote controlled bronchial working channel catheter utilizing electromagnetic tracking and has many implications for future development in endoscopic and catheter-based procedures.

Pre-clinical validation of virtual bronchoscopy using 3D Slicer.

PURPOSE: Lung cancer still represents the leading cause of cancer-related death, and the long-term survival rate remains low. Computed tomography (CT) is currently the most common imaging modality for lung diseases recognition. The purpose of this work was to develop a simple and easily accessible virtual bronchoscopy system to be coupled with a customized electromagnetic (EM) tracking system for navigation in the lung and which requires as little user interaction as possible, while maintaining high usability. METHODS: The proposed method has been implemented as an extension to the open-source platform, 3D Slicer. It creates a virtual reconstruction of the airways starting from CT images for virtual navigation. It provides tools for pre-procedural planning and virtual navigation, and it has been optimized for use in combination with a [Formula: see text] of freedom EM tracking sensor. Performance of the algorithm has been evaluated in ex vivo and in vivo testing. RESULTS: During ex vivo testing, nine volunteer physicians tested the implemented algorithm to navigate three separate targets placed inside a breathing pig lung model. In general, the system proved easy to use and accurate in replicating the clinical setting and seemed to help choose the correct path without any previous experience or image analysis. Two separate animal studies confirmed technical feasibility and usability of the system. CONCLUSIONS: This work describes an easily accessible virtual bronchoscopy system for navigation in the lung. The system provides the user with a complete set of tools that facilitate navigation towards user-selected regions of interest. Results from ex vivo and in vivo studies showed that the system opens the way for potential future work with virtual navigation for safe and reliable airway disease diagnosis.

Loss of flexion during bronchoscopy: a physical experiment and case study of commercially available systems.

During routine endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) procedures, especially with biopsy of lymph nodes in or around the left upper lobe, frequent reports have noted the loss of ultrasound image and needle angulation leading to an inability to biopsy nodes visualised by EBUS. The aim of this research was to investigate and compare this loss of angulation with commercially available scopes. Bench-top experiments and a clinical case study demonstrated the varying loss of scope angulation, flexibility and manoeuvrability with different scopes and biopsy instruments leading to procedural implications. Improvements in both the EBUS scope and needle characteristics are required to overcome this limitation which has implications in bronchoscope navigation and the diagnostic yield of EBUS-TBNA.

Evaluation of Endoscopically Deployed Radiopaque Tumor Models in Bronchoscopy.

BACKGROUND: Radiopaque markers and soft tissue models have been used extensively in clinical applications to target cancerous lesions and to calibrate and characterize imaging systems. However, the development of radiopaque, soft tissue models for pulmonary lesions is yet to be optimized. Such a material may improve endoscopic training techniques and also be useful to evaluate bronchoscopy navigation systems by the targeting and sampling of tumor models with computed tomography. METHODS: This study investigates a modified agarose-based model and a novel contrast-infused tripe model to create clinically relevant pulmonary tumor models. An iodine-enhanced agarose model presents an injectable solution with high image contrast under computed tomography capable of reaching distal bronchial airways. The tripe solution presents a cheap and easily deployed method to quickly establish a fiducial marker that may be used during bronchial imaging system training and evaluation. RESULTS: The iodine-enriched agarose model demonstrates desirable mechanical characteristics ex vivo, but has a number of limitations when administered in a live setting. The tripe solution presents a far more effective in vivo pulmonary tumor model and offers an effective radiopaque marker. However, the size of the tripe tumor samples required for effective insertion limits its ability to reach more distal airways. An iterative testing process was used to optimize the model composition, culminating in live animal investigations (n=3). CONCLUSION: Both contrast-infused agarose and tripe models present a promising analog to a pulmonary lesion and may act as a radiopaque marker for bronchoscopic training and biopsy evaluation.

Navigational Bronchoscopy for Early Lung Cancer: A Road to Therapy.

Peripheral lung nodules remain challenging for accurate localization and diagnosis. Once identified, there are many strategies for diagnosis with heterogeneous risk benefit analysis. Traditional strategies such as conventional bronchoscopy have poor performance in locating and acquiring the required tissue. Similarly, while computerized-assisted transthoracic needle biopsy is currently the favored diagnostic procedure, it is associated with complications such as pneumothorax and hemorrhage. Video-assisted thoracoscopic and open surgical biopsies are invasive, require general anesthesia and are therefore not a first-line approach. New techniques such as ultrathin bronchoscopy and image-based guidance technologies are evolving to improve the diagnosis of peripheral lung lesions. Virtual bronchoscopy and electromagnetic navigation systems are novel technologies based on assisted-computerized tomography images that guide the bronchoscopist toward the target peripheral lesion. This article provides a comprehensive review of these emerging technologies.

Electropermanent magnetic anchoring for surgery and endoscopy.

The use of magnets for anchoring of instrumentation in minimally invasive surgery and endoscopy has become of increased interest in recent years. Permanent magnets have significant advantages over electromagnets for these applications; larger anchoring and retraction force for comparable size and volume without the need for any external power supply. However, permanent magnets represent a potential hazard in the operating field where inadvertent attraction to surgical instrumentation is often undesirable. The current work proposes an interesting hybrid approach which marries the high forces of permanent magnets with the control of electromagnetic technology including the ability to turn the magnet OFF when necessary. This is achieved through the use of an electropermanent magnet, which is designed for surgical retraction across the abdominal and gastric walls. Our electropermanent magnet, which is hand-held and does not require continuous power, is designed with a center lumen which may be used for trocar or needle insertion. The device in this application has been demonstrated successfully in the porcine model where coupling between an intraluminal ring magnet and our electropermanent magnet facilitated guided insertion of an 18 Fr Tuohy needle for guidewire placement. Subsequent investigations have demonstrated the ability to control the coupling distance of the system alleviating shortcomings with current methods of magnetic coupling due to variation in transabdominal wall thicknesses. With further refinement, the magnet may find application in the anchoring of endoscopic and surgical instrumentation for minimally invasive interventions in the gastrointestinal tract.

Design, development and evaluation of an inflatable retractor for atraumatic retraction in laparoscopic colectomy.

Laparoscopic colectomy is the gold standard in the treatment of malignant tumours arising in the mucosa of the colon wall. The procedure is performed under general endotracheal anaesthesia and involves establishing a pneumoperitoneum with the patient in the Trendelenburg position. However this position can cause anaesthetic difficulties due to excess blood flow to the head and neck, increased pressure on the diaphragm and increased venous pressure. In the absence of steep head-down positioning, the bowels fall or "spill" into the operating field, obstructing the surgical space. The primary goal of this work is to design an atraumatic laparoscopic retractor to minimise the Trendelenburg position whilst effectively retracting the bowels from the operating field. This work details the design, evaluation and optimisation of a novel, hand held, inflatable, laparoscopic retractor, through physical experimentation, computer simulation, and pre-clinical animal investigation. The optimised design for the inflatable retractor performs in line with simulated expectations, and was successfully tested for safety and technical feasibility in vivo in a porcine model, where the bowels were effectively removed from the operating space whilst the model remained in the supine position. These initial results represent a promising approach for the mitigation of the Trendelenburg position, whilst effectively retracting the bowels during laparoscopic colectomy, using this atraumatic, inflatable retractor.

Evaluation of a novel tracking system in a breathing lung model.

We present the evaluation of an electromagnetic position tracking system for use with virtual bronchoscopy systems. Our system utilises a planar magnetic coil array and commercially available search coil sensors. Experimental results show the EM tracking accuracy to be in the range of 11.5mm, which is comparable to both commercial and research systems. The use of a bench-top breathing lung model is used to verify system operation in the in vitro setting. A novel fiducial-free registration method is implemented to reduce errors resulting from inaccurate landmark identification commonly associated with point-based registration. After registration, there is good agreement between the measured position of the sensor probe during endoscopic navigation and the lung airways as visualised in a 3D model of the phantom.