Paper
3 March 2012 4D iterative reconstruction in cardiac CT
H. Bruder, R. Raupach, T. Allmendinger, J. Sunnegårdh, K. Stierstorfer, T. Flohr
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Abstract
In this paper, a 4D iterative reconstruction scheme is developed to improve noise characteristics and/or reduce radiation exposure in multi-slice cardiac CT. In our implementation, image volume datasets are reconstructed at adjacent temporal positions with respect to an optimized cardiac phase (best phase). Nonlinear regularization priors operate on a 4D cube surrounding each voxel in 4D space, reducing image noise while maintaining temporal and spatial image sharpness. The temporal resolution of image data is maintained despite the usage of temporal data that can substantially exceed the reconstruction range of the 'best phase' reconstruction. Consequently, the noise statistics is significantly improved because non-correlated image data at different temporal positions are utilized. To reduce the high computational load, the iterative regularization in 4D can be transferred into image space. Raw data based Iterative Reconstruction reducing artifacts due to the non-exactness of the backprojector is decoupled from regularization and restricted to only those projection data belonging to the 'best phase' reconstruction. Finally, the image formation is achieved by a normalized combination of the low frequency part of the raw data based Iterative Reconstruction at cardiac best phase and the high frequency part of the image based regularization image at best phase. We demonstrate the potential of noise reduction on basis of clinical cardiac CT data. As an example for cardiac dual source CT (DSCT) data a noise reduction up to 70% was achieved. Even in case of a very high and irregular heart beat with an average heart rate of 115 bpm the high temporal resolution of DSCT could be maintained.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
H. Bruder, R. Raupach, T. Allmendinger, J. Sunnegårdh, K. Stierstorfer, and T. Flohr "4D iterative reconstruction in cardiac CT", Proc. SPIE 8313, Medical Imaging 2012: Physics of Medical Imaging, 83132E (3 March 2012); https://doi.org/10.1117/12.910890
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KEYWORDS
Temporal resolution

Heart

Denoising

Image filtering

Beam propagation method

Computed tomography

Data acquisition

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