| Spatially varying longitudinal aliasing and resolution in spiral computed tomography. | |
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MedLine Citation:
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PMID: 10619247 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Spiral computed tomography (CT) has revolutionized conventional CT as a truly three-dimensional imaging modality. A number of studies aimed at evaluating the longitudinal resolution in spiral CT have been presented, but the spatially varying nature of the longitudinal resolution in spiral CT has been largely left undiscussed. In this paper, we investigate the longitudinal resolution in spiral CT as affected by the spatially varying longitudinal aliasing. We propose the treatment of aliasing as a signal dependent, additive noise, and define a new image quality parameter, the contrast-to-aliased-noise ratio (CNaR), that relates to possible image degradation or loss of resolution caused by aliasing. We performed CT simulations and actual phantom scans using a resolution phantom consisting of sequences of spherical beads of different diameters, extending along the longitudinal axis. Our results show that the off-isocenter longitudinal resolution differs significantly from the longitudinal resolution at the isocenter and that the CNaR decreases with distance from the isocenter, and is a function of pitch and the helical interpolation algorithm used. The longitudinal resolution was observed to worsen with decreasing CNaR. We conclude that the longitudinal resolution in spiral CT is spatially varying, and can be characterized by the CNaR measured at the transaxial location of interest. |
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Authors:
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S Y Yen; G D Rubin; S Napel |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Medical physics Volume: 26 ISSN: 0094-2405 ISO Abbreviation: Med Phys Publication Date: 1999 Dec |
Date Detail:
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Created Date: 2000-03-13 Completed Date: 2000-03-13 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0425746 Medline TA: Med Phys Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 2617-25 Citation Subset: IM |
Affiliation:
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Department of Electrical Engineering, Information Systems Laboratory, Stanford University, California 94305, USA. shin@s-word.stanford.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Computer Simulation Models, Statistical Phantoms, Imaging Tomography, X-Ray Computed / methods* |
| Grant Support | |
ID/Acronym/Agency:
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1R01-HL50305-01/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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