Magnetic Trackers: Robot Control and Vasculature Imaging - Microsurgery: Advances, Simulations, and Applications - page 250

plaque, and lesion [17], and for providing planning and navigation
information for stent graft deployment as well. Conventionally,
fluoroscopic images of blood vessels are used for guiding the
process of aortic stent graft deployment; for that purpose, a dose 30
mL of contrast media is required along the surgery. However, such
technology only provides two-dimensional information of the aortic
stent graft position related to the vasculature branches, adding
dificulties to the alignment procedure and needs much contrast
media for the whole process. Three-dimensional digital subtraction
angiography (DSA) technology can provide 3D images of blood
vessels; however, it is mainly applied for neurosurgery and requires
more than 55 mL contrast media for descending aorta imaging
in addition to the 30 mL needed for 2D imaging at the beginning
and end of the treatment. Intravascular ultrasounds (IVUS) are
used to obtain two-dimensional images of the blood vessel cross
sections, providing information of lumen morphology for diagnosis
and operation [17-18]. This enables disease diagnosis with less
contrast media than 3D DSA, assessment of the interventions, and
evaluation of treatments after deploying the stent grafts. During
the deployment of stent grafts in descending aorta, the installation
of secondary branches of the stent graft consumes a considerable
amount of time if the stent graft holes are not aligned properly with
the vasculature branches (Fig. 7.21). Such time could be reduced and
the effectiveness of the treatment can be increased if the stent graft
is navigated to align its holes with the artery branches and active
catheters were employed to install the branches.
Sanz-Requena et al. made a 3D reconstruction of artery models
in [19]. This team captured IVUS images from the video recorded on
a VHS tape, and could obtain the distance between cross sections by
pulling back IVUS catheter at the speed of 0.5 mm/s and supposed the
cross section should be parallel to each other. Therefore, this method
can only get one-dimensional depth data of the catheter along blood
vessels whose curvatures are relatively small. Other researchers
have worked on data fusion of IVUS and angiography [20-22], and
they obtained the posture of IVUS tip from angiography images to
get the rough localization of IVUS images. Because of the dificulties
encountered when trying to track the position of an IVUS transducer
using angiography, Godbout et al . proposed a registration approach