TY - JOUR A1 - Maier, Andreas A1 - Wigstrom, Lars A1 - Hofmann, Hannes G A1 - Hornegger, Joachim A1 - Zhu, Lei A1 - Strobel, Norbert A1 - Fahrig, Rebecca T1 - Three-dimensional anisotropic adaptive filtering of projection data for noise reduction in cone beam CT JF - Medical Physic N2 - Purpose: The combination of quickly rotating C-arm gantry with digital flat panel has enabled the acquisition of three-dimensional data (3D) in the interventional suite. However, image quality is still somewhat limited since the hardware has not been optimized for CT imaging. Adaptive anisotropic filtering has the ability to improve image quality by reducing the noise level and therewith the radiation dose without introducing noticeable blurring. By applying the filtering prior to 3D reconstruction, noise-induced streak artifacts are reduced as compared to processing in the image domain. Methods: 3D anisotropic adaptive filtering was used to process an ensemble of 2D x-ray views acquired along a circular trajectory around an object. After arranging the input data into a 3D space (2D projections + angle), the orientation of structures was estimated using a set of differently oriented filters. The resulting tensor representation of local orientation was utilized to control the anisotropic filtering. Low-pass filtering is applied only along structures to maintain high spatial frequency components perpendicular to these. The evaluation of the proposed algorithm includes numerical simulations, phantom experiments, and in-vivo data which were acquired using an AXIOM Artis dTA C-arm system (Siemens AG, Healthcare Sector, Forchheim, Germany). Spatial resolution and noise levels were compared with and without adaptive filtering. A human observer study was carried out to evaluate low-contrast detectability. Results: The adaptive anisotropic filtering algorithm was found to significantly improve low-contrast detectability by reducing the noise level by half (reduction of the standard deviation in certain areas from 74 to 30 HU). Virtually no degradation of high contrast spatial resolution was observed in the modulation transfer function (MTF) analysis. Although the algorithm is computationally intensive, hardware acceleration using Nvidia's CUDA Interface provided an 8.9-fold speed-up of the processing (from 1336 to 150 s). Conclusions: Adaptive anisotropic filtering has the potential to substantially improve image quality and/or reduce the radiation dose required for obtaining 3D image data using cone beam CT. Y1 - 2011 U6 - https://doi.org/10.1118/1.3633901 VL - 38 IS - 11 SP - 5896 EP - 5909 ER - TY - CHAP A1 - Roser, Philipp A1 - Zhong, Xia A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Simultaneous estimation of X-ray back-scatter and forward-scatter using multi-task learning T2 - Medical Image Computing and Computer Assisted Intervention–MICCAI 2020: 23rd International Conference, Lima, Peru, October 4–8, 2020, Proceedings, Part II 23 Y1 - 2020 UR - https://link.springer.com/chapter/10.1007/978-3-030-59713-9_20 U6 - https://doi.org/10.1007/978-3-030-59713-9_20 SP - 199 EP - 208 PB - Springer International Publishing ER - TY - CHAP A1 - Zhong, Xia A1 - Roser, Philipp A1 - Bayer, Siming A1 - Ravikumar, Nishant A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Horz, Tim A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Pediatric Patient Surface Model Atlas Generation and X-Ray Skin Dose Estimation T2 - Bildverarbeitung für die Medizin 2019: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 17. bis 19. März 2019 in Lübeck Y1 - 2019 U6 - https://doi.org/10.1007/978-3-658-25326-4_27 SP - 122 EP - 127 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Deep scatter splines: Learning-based medical X-ray scatter estimation using B-splines T2 - The 6th International Conference on Image Formation in X-Ray Computed Tompgraphy Y1 - 2020 UR - https://arxiv.org/pdf/2005.03470.pdf ER - TY - JOUR A1 - Zhong, Xia A1 - Amrehn, Mario A1 - Ravikumar, Nishant A1 - Chen, Shuqing A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Deep action learning enables robust 3D segmentation of body organs in various CT and MRI images JF - Scientific Reports Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-82370-6 VL - 11 IS - 1 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Stimpel, Bernhard A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Fully-automatic CT data preparation for interventional X-ray skin dose simulation JF - Bildverarbeitung für die Medizin 2020: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 15. bis 17. März 2020 in Berlin Y1 - 2020 U6 - https://doi.org/10.1007/978-3-658-29267-6_26 SP - 125 EP - 130 PB - Springer Fachmedien CY - Wiesbaden ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Ochs, Philipp A1 - Stepina, Elizaveta A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - XDose: toward online cross-validation of experimental and computational X-ray dose estimation JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2020 U6 - https://doi.org/10.1007/s11548-020-02298-6 VL - 16 IS - 2 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Felsner, Lina A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - X-ray Scatter Estimation Using Deep Splines JF - IEEE Transactions on Medical Imaging Y1 - 2021 UR - https://arxiv.org/pdf/2101.09177.pdf VL - 40 IS - 9 SP - 2272 EP - 2283 ER - TY - JOUR A1 - Zhong, Xia A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - A machine learning pipeline for internal anatomical landmark embedding based on a patient surface model JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2019 U6 - https://doi.org/10.1007/s11548-018-1871-y VL - 14 IS - 1 SP - 53 EP - 61 ER -