Diploma thesis
[Subtitle] Real-Time Respiratory Motion Tracking: Roadmap Correction for Endovascular Interventions
Thesis by:
Selen Atasoy
Advisor:
Nassir Navab
Supervision by:
Martin Groher
in collaboration with
Siemens angiography and X-ray
Due date: 15.06.2007
Abstract
Over the past years endovascular interventions became gold standard for treatment
of many diseases such as cancer or blockage of blood flow. These interventions are
performed percutaneously using small instruments such as catheters. While navigating
the catheter through the blood vessels the interventional radiologist relies on
2D X-ray fluoroscopy images, which display the catheter and parts of the patient
anatomy in real-time. However, the visualization of blood vessels is only possible
for a short-period of time when contrast agent is injected. In order to overcome this
limitation 3D roadmaps, which are acquired by rotational angiography, can be overlayed
on live 2D fluoroscopy images. Thus, the amount of contrast agent can be minimized.
Moreover, the procedure time can be reduced by providing a significant help
in catheter navigation. However, in abdominal interventions this technique needs to
be extended by an appropriate respiratory motion correction. In this thesis a method
for real-time respiratory motion correction for 3D static roadmaps is proposed with
the objective of introducing corrected 3D roadmaps into clinical workflow for abdominal
interventions. The proposed method consists of two steps. First, a filtering
is applied to the 2D fluoroscopy images to enhance the catheter and reduce the noise
level. Then, a part of the catheter is tracked in the improved images using templatematching
in order to estimate the catheter motion induced by patient’s respiration.
In order to deal with possible catheter deformations, an adequate template update
strategy is proposed. Real-time implementations of these steps allow an intraoperative
application of the algorithm. The accuracy and robustness of the algorithm
are demonstrated with extensive experimental studies using both simulated image
sequences and clinical image sequences.
Resources
Literature