Endpoint localization in guide wire tracking during endovascular interventions.
OBJECTIVE
A method is presented to track guide wires during endovascular interventions under X-ray fluoroscopy. Accurate guide wire tracking can be used to improve guide wire visualization in the low quality fluoroscopic images, and to estimate the position of the guide wire in world coordinates for navigation purposes.


METHODS
A two-step procedure is used to track the guide wire in subsequent frames. First, the position of the guide wire is obtained by fitting a spline to the image. Subsequently, the spline is iteratively moved toward the tip of the guide wire for accurate tip localization. For both steps, a feature image is used in which line-like structures are enhanced. The method is validated using a reference standard, obtained by manual tracings of three observers.


RESULTS
The method is evaluated on 20 image sequences, 10 sequences with a J-tipped guide wire and 10 with a straight guide wire. The tracking success was 96% for J-tipped and 100% for straight guide wires, whereas accurate endpoint localization could be performed in 91.3% and 94.4% of the frames respectively, with a tip localization error of less than 1.5 mm.


CONCLUSIONS
Accurate endpoint localization can be performed for both J-tipped and straight guide wires and therefore the presented tracking method can be used for navigation purposes.
Baert
Shirley A M
SA
Image Sciences Institute, University Medical Center Utrecht, Room E 01.334, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
van Walsum
Theo
T
Niessen
Wiro J
WJ
D000465:Algorithms; D000792:Angiography; D001808:Blood Vessels; D002404:Catheterization; D005471:Fluoroscopy; D006801:Humans; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015641:Radiography, Interventional; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014656:Vascular Surgical Procedures / Q000379:methods