Respiratory Motion Compensation Using Diaphragm Tracking for Cone-Beam C-Arm CT : A Simulation and a Phantom Study

Abstract EN

Long acquisition times lead to image artifacts in thoracic C-arm CT.

Motion blur caused by respiratory motion leads to decreased image quality in many clinical applications.

We introduce an image-based method to estimate and compensate respiratory motion in C-arm CT based on diaphragm motion.

In order to estimate respiratory motion, we track the contour of the diaphragm in the projection image sequence.

Using a motion corrected triangulation approach on the diaphragm vertex, we are able to estimate a motion signal.

The estimated motion signal is used to compensate for respiratory motion in the target region, for example, heart or lungs.

First, we evaluated our approach in a simulation study using XCAT.

As ground truth data was available, a quantitative evaluation was performed.

We observed an improvement of about 14% using the structural similarity index.

In a real phantom study, using the artiCHEST phantom, we investigated the visibility of bronchial tubes in a porcine lung.

Compared to an uncompensated scan, the visibility of bronchial structures is improved drastically.

Preliminary results indicate that this kind of motion compensation can deliver a first step in reconstruction image quality improvement.

Compared to ground truth data, image quality is still considerably reduced.