Buxin Chen1, Zheng Zhang1, Dan Xia1, Emil Y Sidky1, Xiaochuan Pan1,2. 1. Department of Radiology, The University of Chicago, Chicago, IL, USA. 2. Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, IL, USA.
Abstract
BACKGROUND: Interest exists in dual-energy computed tomography (DECT) imaging with scanning arcs of limited-angular ranges (LARs) for reducing scan time and radiation dose, and for enabling scan configurations of C-arm CT that can avoid possible collision between the rotating X-ray tube/detector and the imaged subject. OBJECTIVE: In this work, we investigate image reconstruction for a type of configurations of practical DECT interest, referred to as the two-orthogonal-arc configuration, in which low- and high-kVp data are collected over two non-overlapping arcs of equal LAR α, ranging from 30° to 90°, separated by 90°. The configuration can readily be implemented, e.g., on CT with dual sources separated by 90° or with the slow-kVp-switching technique. METHODS: The directional-total-variation (DTV) algorithm developed previously for image reconstruction in conventional, single-energy CT is tailored to enable image reconstruction in DECT with two-orthogonal-arc configurations. RESULTS: Performing visual inspection and quantitative analysis of monochromatic images obtained and effective atomic numbers estimated, we observe that the monochromatic images of the DTV algorithm from LAR data are with substantially reduced LAR artifacts, which are observed otherwise in those of existing algorithms, and thus visually correlate reasonably well, in terms of metrics PCC and nMI, with their reference images obtained from full-angular-range data. In addition, effective atomic numbers estimated from LAR data of DECT with two-orthogonal-arc configurations are in reasonable agreement, with relative errors up to ∼ 10%, with those estimated from full-angular-range data in DECT. CONCLUSIONS: The results acquired in the work may yield insights into the design of LAR configurations of practical dual-energy application relevance in diagnostic CT or C-arm CT imaging.
BACKGROUND: Interest exists in dual-energy computed tomography (DECT) imaging with scanning arcs of limited-angular ranges (LARs) for reducing scan time and radiation dose, and for enabling scan configurations of C-arm CT that can avoid possible collision between the rotating X-ray tube/detector and the imaged subject. OBJECTIVE: In this work, we investigate image reconstruction for a type of configurations of practical DECT interest, referred to as the two-orthogonal-arc configuration, in which low- and high-kVp data are collected over two non-overlapping arcs of equal LAR α, ranging from 30° to 90°, separated by 90°. The configuration can readily be implemented, e.g., on CT with dual sources separated by 90° or with the slow-kVp-switching technique. METHODS: The directional-total-variation (DTV) algorithm developed previously for image reconstruction in conventional, single-energy CT is tailored to enable image reconstruction in DECT with two-orthogonal-arc configurations. RESULTS: Performing visual inspection and quantitative analysis of monochromatic images obtained and effective atomic numbers estimated, we observe that the monochromatic images of the DTV algorithm from LAR data are with substantially reduced LAR artifacts, which are observed otherwise in those of existing algorithms, and thus visually correlate reasonably well, in terms of metrics PCC and nMI, with their reference images obtained from full-angular-range data. In addition, effective atomic numbers estimated from LAR data of DECT with two-orthogonal-arc configurations are in reasonable agreement, with relative errors up to ∼ 10%, with those estimated from full-angular-range data in DECT. CONCLUSIONS: The results acquired in the work may yield insights into the design of LAR configurations of practical dual-energy application relevance in diagnostic CT or C-arm CT imaging.
Entities:
Keywords:
DECT; directional total variation; limited-angular range; two-orthogonal-arc
Authors: Thomas G Flohr; Cynthia H McCollough; Herbert Bruder; Martin Petersilka; Klaus Gruber; Christoph Süss; Michael Grasruck; Karl Stierstorfer; Bernhard Krauss; Rainer Raupach; Andrew N Primak; Axel Küttner; Stefan Achenbach; Christoph Becker; Andreas Kopp; Bernd M Ohnesorge Journal: Eur Radiol Date: 2005-12-10 Impact factor: 5.315
Authors: Junguo Bian; Jeffrey H Siewerdsen; Xiao Han; Emil Y Sidky; Jerry L Prince; Charles A Pelizzari; Xiaochuan Pan Journal: Phys Med Biol Date: 2010-10-20 Impact factor: 3.609