A method for the determination of the 3D orientations and positions of catheters from single-plane x-ray images
The three-dimensional (3D) orientation and position of an object, i.e., a configuration of points, can be determined by use of the single projection technique (SPT) from a single projection image, given the relative 3D positions of the points and initial estimates of the orientation and position. The accuracy of the SPT for the case of L-shaped catheters was evaluated in simulation studies. Catheter models were generated, oriented and positioned, and then projected onto an image plane to generate projection images. Gaussian-distributed noise was added to the image positions. The 3D orientations and positions of the catheters were determined using the SPT, which iteratively aligns the model points with their respective image positions. Studies indicate that the orientation and position of a catheter of diameter 0.18 cm can be determined to within 1.6° and 0.8 cm, respectively. These results are comparable to those obtained with a J-shaped catheter indicating that the technique is generally applicable independent of catheter shape. Studies indicate that the SPT may provide the basis for the automated determination of the orientations of catheters in vivo from single-plane projection images. This automated method may facilitate interventional procedures by eliminating the need for imaging the vasculature at various angulations of the gantry, and may, thereby, reduce procedure times, complications, and radiation dose. In the future, the information provided by the SPT may be employed by 3D vessel reconstruction techniques to extend conventional roadmapping techniques from 2D to 3D.