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Dept. of Computer Sc. » Pattern Recognition » Our Team » Rohkohl, Christopher » Projects » Image-Based Gating
Dr.-Ing. Christopher RohkohlAlumnus of the Pattern Recognition Lab of the Friedrich-Alexander-Universität Erlangen-NürnbergThe vision of my work is to develop methods that open up the possibility to visualize highly dynamic (moving) vital parts of the human body as the heart. This provides one key towards the development of novel diagnostic tools and medical treatment procedures. Research Project: Image-Based GatingMethod Overview
Applying the concept of retrospective electrocardiogram gating (ECG) to the acquisition of
multiple, ECG-triggered rotational acquisitions using a C-arm system allows the 3D+t reconstruction of the
heart. The process of retrospective gating is a crucial component of 3-D reconstruction. The gold-standard
in gating is still ECG based. However, the ECG signal does not directly reflect the mechanical situation of
the heart. Therefore an alternative gating method, based on the acquired projection data is required. Our
goal is to provide an image-based gating (IBG) method without ECG such that already acquired projection
data from a multi-sweep acquisition can still be used for reconstruction. We formulate the gating problem as a
shortest-path optimization problem. All acquired projection images build a directed graph and the path costs are
defined by projection image similarities that are based on image metrics to measure the heart phase similarity.
The optimization is additionally regularized to prefer solutions where the path segment of consecutive selected
projections acquired along a particular forward or backward C-arm sweep is short. This regularization depends
on an estimated average heart rate that is also estimated using an image-based method. First promising results
using in-vivo data are presented and compared to standard ECG gating.
Results
Publications
Cardiac C-arm CT: image-based gating In: Hsieh, J.; Samei, E. (Eds.) Medical Imaging 2008: Physics of Medical Imaging. Proceedings of the SPIE. (Medical Imaging 2008: Physics of Medical Imaging. Proceedings of the SPIE. San Diego 16.-21.02.2008) 2008, pp. online (BiBTeX) |