Document Detail


Multi-frequency encoding for fast color flow or quadroplex imaging.
MedLine Citation:
PMID:  18467222     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Ultrasonic color flow maps are made by estimating the velocities line by line over the region of interest. For each velocity estimate, multiple repetitions are needed. This sets a limit on the frame rate, which becomes increasingly severe when imaging deeper lying structures or when simultaneously acquiring spectrogram data for triplex imaging. This paper proposes a method for decreasing the data acquisition time by simultaneously sampling multiple lines for color flow maps, using narrow band signals with approximately disjoint spectral support. The signals are separated in the receiver by filters matched to the emitted waveforms, producing a number of data sets with different center frequencies. The autocorrelation estimator is then applied to each of the data sets. The method is presented, various side effects are considered, and the method is tested on data from a recirculating flow phantom. A mean standard deviation across the flow profile of 3.1, 2.5, and 2.1% of the peak velocity was found for bands at 5 MHz, 7 MHz, and 9 MHz, respectively. Alternatively, the method can be used for simultaneously sampling data for a color flow map and for multiple spectrograms using different spectral bands. Using three spectral bands, data for a color flow map and two independent spectrograms can be acquired at the time normally spent on acquiring data for a color flow map only. This yields an expansion of triplex imaging called multifrequency quadroplex imaging, which enables study of the flow over an arterial stenosis by simultaneously acquiring spectrograms on both sides of the stenosis, while maintaining the color flow map. The method was tested in vivo on data from the common carotid artery of a healthy male volunteer, both for fast color flow mapping and for multifrequency quadroplex imaging.
Authors:
Niels Oddershede; Fredrik Gran; Jørgen Arendt Jensen
Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  IEEE transactions on ultrasonics, ferroelectrics, and frequency control     Volume:  55     ISSN:  0885-3010     ISO Abbreviation:  IEEE Trans Ultrason Ferroelectr Freq Control     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-05-09     Completed Date:  2008-06-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882735     Medline TA:  IEEE Trans Ultrason Ferroelectr Freq Control     Country:  United States    
Other Details:
Languages:  eng     Pagination:  778-86     Citation Subset:  IM    
Affiliation:
Center for Fast Ultrasound Imaging, Technical University of Denmark, Lyngby, Denmark. no@oersted.dtu.dk
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MeSH Terms
Descriptor/Qualifier:
Adult
Algorithms*
Blood Flow Velocity / physiology*
Carotid Arteries / physiology,  ultrasonography*
Cerebrovascular Circulation / physiology*
Data Compression / methods*
Humans
Image Enhancement / methods
Male
Phantoms, Imaging
Reproducibility of Results
Rheology / methods*
Sensitivity and Specificity
Signal Processing, Computer-Assisted
Ultrasonography, Doppler, Color / methods*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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