TIPS placement in swine, guided by electromagnetic real-time needle tip localization displayed on previously acquired 3-D CT.

PURPOSE: To determine the feasibility of guiding a transjugular intrahepatic portosystemic shunt (TIPS) procedure with an electromagnetic real-time needle tip position sensor coupled to previously acquired 3-dimensional (3-D) computed tomography (CT) images. METHODS: An electromagnetic position sensor was placed at the tip of a Colapinto needle. The real-time position and orientation of the needle tip was then displayed on previously acquired 3-D CT images which were registered with the five swine. Portal vein puncture was then attempted in all animals. RESULTS: The computer calculated accuracy of the position sensor was on average 3 mm. Four of five portal vein punctures were successful. In the successes, only one or two attempts were necessary and success was achieved in minutes. CONCLUSION: A real-time position sensor attached to the tip of a Colapinto needle and coupled to previously acquired 3-D CT images may potentially aid in entering the portal vein during the TIPS procedure.

Image-guided surgery of the skull base using a novel miniature position sensor.

Image-guided navigational systems have been a useful adjunct for minimally invasive surgery of the skull base. A novel miniature position sensor has been developed that uses a low magnetic field for real-time tracking of surgical instruments. The 1.7-mm-diameter sensor attached to the position and orientation system (Magellan(R), Biosense, Inc., Johnson and Johnson Co., Baldwin Park, CA) was deployed through various surgical instruments or used in a hand-held fashion with a malleable shaft probe. We report on our experience using this electromagnetic system in a series of lesions of the sella and clivus. After patient/image registration, the system was consistently accurate to within 2 mm. We have found this system to be particularly advantageous in endoscopic surgery of cystic lesions of the skull base, where access is limited and anatomy may be distorted. In three patients, this device obviated the need for an extensive external surgical approach. Case histories are presented, which illustrate the specific advantages this miniature system provides during skull base surgery.

Real-time bronchoscope tip localization enables three-dimensional CT image guidance for transbronchial needle aspiration in swine.

STUDY OBJECTIVE: To determine the feasibility of using real-time bronchoscope position technology coupled with previously acquired three-dimensional CT data to enhance transbronchial needle aspiration (TBNA). DESIGN: Eight swine were given percutaneously created target lesions for TBNA. A miniature position sensor was placed at the tip of a bronchoscope, and real-time position information during bronchoscopy was presented on a monitor simultaneously displaying previously acquired three-dimensional CT data. INTERVENTIONS: TBNA of target lesions and submucosal ink-spot injection of computer-generated targets. MEASUREMENTS AND RESULTS: TBNA specimens revealed successful aspiration of target material. Distances between ink marks made at computer-generated tracheal targets varied, on average (+/- SD), 4.2 mm +/- 2.6 mm from predetermined computer-distance coordinates. CONCLUSION: Real-time bronchoscope position technology coupled with previously acquired CT images may aid with TBNA of nonvisible extrabronchial lesions.