TY - JOUR A1 - Fahrig, Rebecca A1 - Dixon, Robert A1 - Payne, Thomas A1 - Morin, Richard L. A1 - Ganguly, Arundhuti A1 - Strobel, Robert T1 - Dose and Image Quality for a Cone-Beam C-arm CT System JF - Medical Physics N2 - We assess dose and image quality of a state-of-the-art angiographic C-arm system (Axiom Artis dTA, Siemens Medical Solutions, Forchheim, Germany) for three-dimensional neuro-imaging at various dose levels and tube voltages and an associated measurement method. Unlike conventional CT, the beam length covers the entire phantom, hence, the concept of computed tomography dose index (CTDI) is not the metric of choice, and one can revert to conventional dosimetry methods by directly measuring the dose at various points using a small ion chamber. This method allows us to define and compute a new dose metric that is appropriate for a direct comparison with the familiar CTDIw of conventional CT. A perception study involving the CATPHAN 600 indicates that one can expect to see at least the 9 mm inset with 0.5% nominal contrast at the recommended head-scan dose (60 mGy) when using tube voltages ranging from 70 kVp to 125 kVp. When analyzing the impact of tube voltage on image quality at a fixed dose, we found that lower tube voltages gave improved low contrast detectability for small-diameter objects. The relationships between kVp, image noise, dose, and contrast perception are discussed. Y1 - 2006 U6 - https://doi.org/10.1118/1.2370508 VL - 33 IS - 12 SP - 4541 EP - 4550 ER - TY - JOUR A1 - Sze, Daniel Y. A1 - Strobel, Norbert A1 - Fahrig, Rebecca A1 - Moore, Teri A1 - Busque, Stephan A1 - Frisoli, Joan K. T1 - Transjugular intrahepatic portosystemic shunt creation in a polycystic liver facilitated by hybrid cross-sectional/angiographic imaging JF - Journal of Vascular and Interventional Radiology (JVIR) N2 - Polycystic liver disease (PCLD) has long been considered to represent a contraindication to transjugular intrahepatic portosystemic shunt (TIPS) creation, primarily because of the risk of hemorrhage. Three-dimensional (3D) navigation within the enlarged and potentially disorienting parenchyma can now be performed during the procedure with the development of C-arm cone-beam computed tomography, which relies on the same equipment already used for angiography. Such a hybrid 3D reconstruction-enabled angiography system was used for safe image guidance of a TIPS procedure in a patient with PCLD. This technology has the potential to expedite any image-guided procedure that requires 3D navigation. Y1 - 2006 U6 - https://doi.org/10.1097/01.rvi.0000208984.17697.58 VL - 17 IS - 4 SP - 711 EP - 715 ER - TY - JOUR A1 - Bourier, Felix A1 - Fahrig, Rebecca A1 - Wang, Paul A1 - Santangeli, Pasquale A1 - Kurzidim, Klaus A1 - Strobel, Norbert A1 - Moore, Teri A1 - Hinkel, Cameron A1 - Al-Ahmad, Amin T1 - Accuracy assessment of catheter guidance technology in electrophysiology procedures: a comparison of a new 3D-based fluoroscopy navigation system to current electroanatomic mapping system JF - Journal of Cardiovascular Electrophysiology N2 - Background: With increasing complexity in electrophysiology (EP) procedures, the use of electroanatomic mapping systems (EAMS) as a supplement to fluoroscopy has become common practice. This is the first study that evaluates spatial and point localization accuracy for 2 current EAMS, CARTO3(®) (Biosense Webster, Diamond Bar, CA, USA) and EnSite Velocity(®) (St. Jude Medical Inc., St. Paul, MN, USA), and for a novel overlay guidance (OG) software (Siemens AG, Forchheim, Germany) in a phantom experiment. Methods and results: A C-arm CT scan was performed on an acrylic phantom containing holes and location markers. Spatial accuracy was assessed for each system using distance measurements involving known markers inside the phantom and properly placed catheters. Anatomical maps of the phantom were acquired by each EAMS, whereas the 3D-based OG software superimposed an overlay image of the phantom, segmented from the C-arm CT data set, onto biplane fluoroscopy. Registration processes and landmark measurements quantitatively assessed the spatial accuracy of each technology with respect to the ground truth phantom. Point localization performance was 0.49 ± 0.25 mm in OG, 0.46 ± 0.17 mm in CARTO3(®) and 0.79 ± 0.83 mm in EnSite(®) . The registration offset between virtual visualization and reality was 1.10 ± 0.52 mm in OG, 1.62 ± 0.77 mm in CARTO3(®) and 2.02 ± 1.21 mm in EnSite(®) . The offset to phantom C-arm CT landmark measurements was 0.30 ± 0.26 mm in OG, 0.24 ± 0.21 mm in CARTO3(®) and 1.32 ± 0.98 mm in EnSite(®) . Conclusions: Each of the evaluated EP guidance systems showed a high level of accuracy; the observed offsets between the virtual 3D visualization and the real phantom were below a clinically relevant threshold of 3 mm. Y1 - 2013 U6 - https://doi.org/10.1111/jce.12264 VL - 25 IS - 1 SP - 74 EP - 83 ER - 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 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Albarqouni, Shadi A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Learning-based X-ray image denoising utilizing model-based image simulations T2 - International Conference on Medical Image Computing and Computer-Assisted Intervention - MICCAI 2019, 22nd International Conference Shenzhen, China, October 13-17, 2019 Proceedings, Part VI Y1 - 2019 U6 - https://doi.org/10.1007/978-3-030-32226-7_61 SP - 549 EP - 557 PB - Springer International Publishing CY - Cham ER - TY - CHAP A1 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - DiNitto, Julie A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Model-based motion artifact correction in digital subtraction angiography using optical-flow 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_31 SP - 146 EP - 151 PB - Springer Fachmedien CY - Wiesbaden 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 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Robust learning-based x-ray image denoising—potential pitfalls, their analysis and solutions JF - Biomedical Physics & Engineering Express Y1 - 2022 U6 - https://doi.org/10.1088/2057-1976/ac3489 VL - 8 IS - 3 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 - Hariharan, Sai Gokul A1 - Strobel, Norbert A1 - Kaethner, Christian A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Data-driven estimation of noise variance stabilization parameters for low-dose x-ray images JF - Physics in Medicine and Biology Y1 - 2020 U6 - https://doi.org/10.1088/1361-6560/abbc82 VL - 65 IS - 22 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 -