| Sampling and aliasing consequences of quarter-detector offset use in helical CT. | |
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MedLine Citation:
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PMID: 15191148 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In this paper, the sampling and aliasing consequences of employing a quarter-detector-offset (QDO) in helical computed tomography (CT) are analyzed. QDO is often used in conventional CT to reduce in-plane aliasing by eliminating data redundancies to improve radial sampling. In helical CT, these same redundancies are exploited to improve longitudinal sampling and so it might seem ill-advised to employ QDO. The relative merit of the two geometries for helical CT is studied by conducting a multidimensional sampling analysis of projection-space sampling as well as a Fourier crosstalk analysis of crosstalk among the object's Fourier basis components. Both a standard fanbeam helical CT geometry and a hypothetical parallel-beam CT geometry, which helps illuminate the more complicated fanbeam results, are analyzed. Using the sampling analysis, it was found that the use of QDO leads to very different spectral tiling than arise when not using QDO. However, due to the shape of the essential support of the projection data spectra that arises in practice, both configurations lead to very similar or identical amounts of spectral overlap. This perspective also predicts the spatially variant longitudinal aliasing that has been observed in helical CT. The crosstalk results were consistent with those of the multidimensional sampling analysis. Thus, from the standpoint of aliasing and crosstalk, no compelling difference is found between the two geometries. |
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Authors:
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Patrick J La Rivière; Xiaochuan Pan |
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Publication Detail:
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Type: Comparative Study; Evaluation Studies; Journal Article; Research Support, U.S. Gov't, P.H.S.; Validation Studies |
Journal Detail:
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Title: IEEE transactions on medical imaging Volume: 23 ISSN: 0278-0062 ISO Abbreviation: IEEE Trans Med Imaging Publication Date: 2004 Jun |
Date Detail:
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Created Date: 2004-06-11 Completed Date: 2004-09-01 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 8310780 Medline TA: IEEE Trans Med Imaging Country: United States |
Other Details:
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Languages: eng Pagination: 738-49 Citation Subset: IM |
Affiliation:
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Department of Radiology, The University of Chicago, Chicago, IL 60637, USA. pjlarivi@midway.uchicago.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Algorithms Artifacts* Head / radiography Humans Imaging, Three-Dimensional / methods* Phantoms, Imaging Radiographic Image Enhancement / methods* Radiographic Image Interpretation, Computer-Assisted / methods* Reproducibility of Results Sample Size Sensitivity and Specificity Signal Processing, Computer-Assisted* Tomography, Spiral Computed / methods* |
| Grant Support | |
ID/Acronym/Agency:
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R01CA70449/CA/NCI NIH HHS; R01EB00225/EB/NIBIB NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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