Showing papers by "Yili Fu published in 2009"

Steerable catheters in minimally invasive vascular surgery.

Abstract: Background Remote-controlled catheter navigation systems have recently been introduced into minimally invasive vascular surgery and some of them have already been applied in clinical practice. Steerable catheters with improved manoeuvrability play an important role in these innovations for conventional catheterization. Methods This review details the development of various steerable catheters, both in use clinically and under investigation. Comprehensive comparison and analysis in several key aspects are followed to reveal both the advantages and limitations of these catheters, as well as the requirements for relevant techniques. Results Steerable catheters are able to select direction in the distal end, and superior to conventional counterparts in many aspects. Differences between magnetic and active catheters mainly lie in function, safety, configuration of operating room and cost. They have similar requirements for miniaturization and slave insertion mechanisms. Conclusions Steerable catheters are rapidly evolving and still require technological refinements to extend current capabilities. Copyright © 2009 John Wiley & Sons, Ltd.

Skeleton-based active catheter navigation.

Abstract: Background The emergence of the active catheter has prompted the development of catheterization in minimally invasive surgery. However, it is still operated using only the physician's vision; information supplied by the guiding image and tracking sensors has not been fully utilized. Methods In order to supply the active catheter with more useful information for automatic navigation, we extract the skeleton of blood vessels by means of an improved distance transform method, and then present the crucial geometric information determining navigation. With the help of tracking sensors' position and pose information, two operations, advancement in the proximal end and direction selection in the distal end, are alternately implemented to insert the active catheter into a target blood vessel. Results The skeleton of the aortic arch reconstructed from slice images is extracted fast and automatically. A navigation path is generated on the skeleton by manually selecting the start and target points, and smoothed with the cubic cardinal spline curve. Crucial geometric information determining navigation is presented, as well as requirements for the catheter entering the target blood vessel. Using a shape memory alloy active catheter integrated with magnetic sensors, an experiment is carried out in a vascular model, in which the catheter is successfully inserted from the ascending aorta, via the aortic arch, into the brachiocephalic trunk. Conclusions The navigation strategy proposed in this paper is feasible and has the advantage of increasing the automation of catheterization, enhancing the manoeuvrability of the active catheter and providing the guiding image with desirable interactivity. Copyright © 2009 John Wiley & Sons, Ltd.

Computer-assisted automatic localization of the human pedunculopontine nucleus in T1-weighted MR images: a preliminary study.

Abstract: Background The pedunculopontine nucleus (PPN) is a new promising target of deep brain stimulation (DBS) for the treatment of Parkinson's disease. This study was to develop a method of computer-assisted automatic localization of the PPN in T1-weighted MR images. Methods A 3D template of a segment of the brainstem containing the PPN was constructed. A knowledge-based, hierarchical method of template-to-subject registration was proposed to register the template to the subject's data to locate the subject's PPN. Results Experiments were performed with both T1-weighted and proton density MR images acquired from 12 people. Preliminary results show that the proposed method can locate the PPN with an error of 1.83 ± 0.42 mm for its rostral pole and 1.57 ± 0.34 mm for its caudal pole. Conclusion The proposed method is automatic, robust and accurate in the localization of the PPN, which demonstrates utility for preoperative surgical planning. Copyright © 2009 John Wiley & Sons, Ltd.