WarpEM: Dynamic Time Warping for Accurate Catheter Registration in
  EM-guided Procedures
Ardit Ramadani Peter Ewert Heribert Schunkert Nassir Navab
Accurate catheter tracking is crucial during minimally invasive endovascular
procedures (MIEP), and electromagnetic (EM) tracking is a widely used
technology that serves this purpose. However, registration between preoperative
images and the EM tracking system is often challenging. Existing registration
methods typically require manual interactions, which can be time-consuming,
increase the risk of errors and change the procedural workflow. Although
several registration methods are available for catheter tracking, such as
marker-based and path-based approaches, their limitations can impact the
accuracy of the resulting tracking solution, consequently, the outcome of the
medical procedure.
  This paper introduces a novel automated catheter registration method for
EM-guided MIEP. The method utilizes 3D signal temporal analysis, such as
Dynamic Time Warping (DTW) algorithms, to improve registration accuracy and
reliability compared to existing methods. DTW can accurately warp and match
EM-tracked paths to the vessel's centerline, making it particularly suitable
for registration. The introduced registration method is evaluated for accuracy
in a vascular phantom using a marker-based registration as the ground truth.
The results indicate that the DTW method yields accurate and reliable
registration outcomes, with a mean error of $2.22$mm. The introduced
registration method presents several advantages over state-of-the-art methods,
such as high registration accuracy, no initialization required, and increased
automation.