| Accurate geometric calibration in stepping-table digital subtraction angiography. | |
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MedLine Citation:
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PMID: 17875596 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Accurate measurements of vessel dimensions are desirable in many clinical applications. This work uses the known relative motion between X-ray source and the patient in stepping-table digital subtraction angiography (DSA) to provide an accurate geometric calibration for quantitative measurements. The method results in a calibration factor that converts the size of the object measured in pixels on the image to its size in millimetres. The main sources of error relate to: (i) the assessment of relative displacement of a structure in a series of images; (ii) patient motion throughout data acquisition; and (iii) image distortion. Error was evaluated both with a test object consisting of a large grid of ball bearings (2x2 cm spaced) and, in vivo, in five renal DSA examinations performed with identical catheters of known diameter. The calibration factor was calculated with 0.1% accuracy for the test object and at least 2% accuracy in vivo, even with breath holding and pulsatile motion. This demonstrates that the calculation of the calibration factor can be very accurate, and that the method we propose is capable of the submillimetre accuracy required for clinical studies if used in conjunction with an accurate measurement of the vessel size in pixels. In conclusion, accurate geometric measurements can be performed in stepping-table DSA, without the need for external reference objects. |
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Authors:
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M A Schmidt; S L Nayak; A-M Belli; A J Britten |
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Publication Detail:
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Type: Evaluation Studies; Journal Article Date: 2007-09-17 |
Journal Detail:
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Title: The British journal of radiology Volume: 80 ISSN: 1748-880X ISO Abbreviation: Br J Radiol Publication Date: 2007 Oct |
Date Detail:
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Created Date: 2007-10-25 Completed Date: 2007-11-26 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0373125 Medline TA: Br J Radiol Country: England |
Other Details:
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Languages: eng Pagination: 835-40 Citation Subset: AIM; IM |
Affiliation:
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Department of Medical Physics, St George's Hospital, London SW17 0QT, UK. maria.schmidt@stgeorges.nhs.uk |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Angiography, Digital Subtraction
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standards* Calibration Humans Radiographic Image Enhancement Radiographic Image Interpretation, Computer-Assisted / standards Reproducibility of Results Sensitivity and Specificity |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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