| Doppler color imaging. Principles and instrumentation. | |
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MedLine Citation:
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PMID: 1497942 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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DCI acquires Doppler-shifted echoes from a cross-section of tissue scanned by an ultrasound beam. These echoes are then presented in color and superimposed on the gray-scale anatomic image of non-Doppler-shifted echoes received during the scan. The flow echoes are assigned colors according to the color map chosen. Usually red, yellow, or white indicates positive Doppler shifts (approaching flow) and blue, cyan, or white indicates negative shifts (receding flow). Green is added to indicate variance (disturbed or turbulent flow). Several pulses (the number is called the ensemble length) are needed to generate a color scan line. Linear, convex, phased, and annular arrays are used to acquire the gray-scale and color-flow information. Doppler color-flow instruments are pulsed-Doppler instruments and are subject to the same limitations, such as Doppler angle dependence and aliasing, as other Doppler instruments. Color controls include gain, TGC, map selection, variance on/off, persistence, ensemble length, color/gray priority. Nyquist limit (PRF), baseline shift, wall filter, and color window angle, location, and size. Doppler color-flow instruments generally have output intensities intermediate between those of gray-scale imaging and pulsed-Doppler duplex instruments. Although there is no known risk with the use of color-flow instruments, prudent practice dictates that they be used for medical indications and with the minimum exposure time and instrument output required to obtain the needed diagnostic information. |
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Authors:
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F W Kremkau |
Publication Detail:
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Type: Journal Article; Review |
Journal Detail:
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Title: Clinics in diagnostic ultrasound Volume: 27 ISSN: 0193-743X ISO Abbreviation: Clin Diagn Ultrasound Publication Date: 1992 |
Date Detail:
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Created Date: 1992-09-17 Completed Date: 1992-09-17 Revised Date: 2005-11-16 |
Medline Journal Info:
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Nlm Unique ID: 7904770 Medline TA: Clin Diagn Ultrasound Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 7-60 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Artifacts Color Doppler Effect Humans Regional Blood Flow Transducers Ultrasonics Ultrasonography* / instrumentation, methods |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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