N. Ayache, S. Ourselin, A. Maeder (Eds.): MICCAI 2007, Part II, LNCS 4792, pp. 636–643, 2007.
© Springer-Verlag Berlin Heidelberg 2007
Rotational Roadmapping: A New Image-Based
Navigation Technique for the Interventional Room
Markus Kukuk1,2 and Sandy Napel2
1 Siemens Medical Solutions, Forchheim, Germany
2 Stanford University, Department of Radiology, USA
Abstract. For decades, conventional 2D-roadmaping has been the method of
choice for image-based guidewire navigation during endovascular procedures.
Only recently have 3D-roadmapping techniques become available that are
based on the acquisition and reconstruction of a 3D image of the vascular tree.
In this paper, we present a new image-based navigation technique called RoRo
(Rotational Roadmapping) that eliminates the guess-work inherent to the con-
ventional 2D method, but does not require a 3D image. Our preliminary clinical
results show that there are situations in which RoRo is preferred over the exist-
ing two methods, thus demonstrating potential for filling a clinical niche and
complementing the spectrum of available navigation tools.
The number and breadth of minimally invasive, image-guided therapies is ever in-
creasing. Of particular interest are endovascular procedures, which allow minimally
invasive access to all areas of the human body through the vascular system as, for ex-
ample angioplasty, vascular stenting, embolization, chemoembolization, thrombolysis
and TIPS (Transjugular Intrahepatic Portosystemic Shunt). These procedures are typi-
cally performed in an interventional room using C-arm based X-ray imaging (see Fig.
1), together with the selective injection of contrast material for blood vessel opacifica-
tion. Common to all endovascular procedures is the navigation of a guidewire or
catheter through the vasculature to a target site. Depending on the degree of tortu-
ousity and structural complexity of the vascular tree, especially in diseased vascula-
ture, guidance (image- or sensor-based ) is often required for targeted steering.
Essentially unchanged from its first introduction in the early 1980s, a technique
called 2D-roadmapping  has long become clinical routine for image-based
guidewire navigation. The basic idea is to acquire an image of the vasculature of in-
terest and to store it as a “roadmap” image. Then, the guidewire or other instrument as
shown under live fluoroscopy is continuously superimposed onto the roadmap image,
thus visualizing the instrument with respect to the vasculature. For acquiring the
roadmap image, the interventionalist estimates how to position the C-arm for finding
a suitable working view, which is considered ideal if it shows the vessel bifurcation to
be negotiated perpendicular to the viewing direction, thus eliminating self occlusion.
However, the vessel tree is visible only after the injection of contrast media, which
Rotational Roadmapping 643
4 Discussion and Conclusion
RoRo effectively eliminates the main limitation of the 2D roadmapping technique, by
allowing the interventionalist to visually select the best working view. In addition,
RoRo provides depth perception through stereoscopic viewing, allowing the assess-
ment of vessel trajectories in 3D. While the 3D roadmapping technique appears to be
the method of choice in cases where a high quality 3D image can be acquired, in
clinical practice this is a challenging task, since several factors have to be taken into
account: cardiac and respiratory motion, bolus timing, filling artifacts, acquisition
speed, washout rate, acquisition range and the presence of metal artifacts. Each of
these factors can greatly compromise image quality and therefore the use of the image
for roadmap navigation. Unfortunately, their presence and extent is often realized
only after image acquisition, when the contrast material and radiation has already
been administered. Until now, in such cases, the interventionalist is forced to fall back
to the 2D roadmapping technique.
In contrast, we propose a roadmapping technique that is robust, flexible and
contrast media efficient with respect to image acquisition. “Robust,” because road-
mapping is done directly on the 2D projection images without performing image re-
construction, and “flexible,” because acquisition parameters can be adapted. For
example, a fast 2s acquisition can be performed, covering 72˚, while the fastest 3D
acquisition is currently 5s. At the same time, image quality can be optimized by per-
forming a 3s acquisition at a 2k matrix size and 0.15mm pixel size, covering 45˚.
RoRo can be considered “contrast media efficient” since it requires an amount of con-
trast equivalent to the acquisition of only 2-4 conventional 2D roadmaps.
RoRo can be used directly, if a 3D acquisition is not considered, or as a fall-back
method by using the projections that resulted in a reconstruction of insufficient image
quality. RoRo has the potential of filling the gap between the 2D and 3D roadmapping
techniques. More clinical studies are currently under way to explore applications in
neuro and body imaging.
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