Based on a phantom study with a realistic coronary vessel phantom, we investigated if motion compensated cardiac CT reconstruction can improve best phase image quality with respect to motion artifacts and patency of coronary vessel lumen. Basically, tracking based methods (with and without improvement of temporal resolution) deriving the motion fields by a registration-like procedure are compared to optimization based methods optimizing objective functions while minimizing artifact levels (e.g. Motion Artifact Metric Optimization (MAM) Reconstruction). Using the MAM technique, the motion field is iteratively calculated with a steepest descent update equation minimizing a motion artifact metric. We evaluated patency of the vessel lumen, the normalized cross correlation (NCC) of the respective reconstruction data with the ground truth data and a best phase improvement index correlating the motion compensated reconstruction data to the non-compensated FDK-based reconstruction data. It will be shown that the MAM technique is superior to the tracking methods. The latter proved to be more or less susceptible to template matching and, or erroneous template size. The value of MAM is also demonstrated evaluating clinical data. In particular it is beneficial for patients with high heart rates as well as for dose optimized scan protocols because it does not need over-radiation.

Date Published: 6 March 2013
PDF: 12 pages
Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 86681T (6 March 2013); doi: 10.1117/12.2006323

Published in SPIE Proceedings Vol. 8668:
Medical Imaging 2013: Physics of Medical Imaging
Robert M. Nishikawa; Bruce R. Whiting; Christoph Hoeschen, Editor(s)