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.
As the importance and prevalence of electromagnetic tracking in medical and industrial applications increases, the need for customized sensor design has escalated. This work focuses on AC-based electromagnetic tracking systems where off-the-shelf inductive sensors may not be optimal for many medical instruments or tracking applications. We present a repeatable approach for the design, optimisation and implementation of air-core and ferrite-core inductive sensors suitable for AC-based electromagnetic tracking. Coil-based sensors were designed and tested to investigate the effect of the usual coil parameters such as turn count, geometry and core material on sensor tracking accuracy and precision. Our methodologies were experimentally validated using the Anser EMT system which enabled rapid experimental deployment. Experimental performance is reported compared to off-the-shelf sensors. Static tracking errors of less than 2mm were achieved and close correlation with theoretical design sensitivity and precision was observed. This work may represent a valuable tool in the design of bespoke sensors for electromagnetic tracking where customize sensitivity and form factor are critical.
25 August 2015 in International Journal of Computer Assisted Radiology and Surgery
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.
20 March 2019 in IEEE Transactions on Instrumentation and Measurement