Document Detail


High-frequency attenuation and backscatter measurements of rat blood between 30 and 60 MHz.
MedLine Citation:
PMID:  20844333     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
There has recently been a great deal of interest in noninvasive high-frequency ultrasound imaging of small animals such as rats due to their being the preferred animal model for gene therapy and cancer research. Improving the interpretation of the obtained images and furthering the development of the imaging devices require a detailed knowledge of the ultrasound attenuation and backscattering of biological tissue (e.g. blood) at high frequencies. In the present study, the attenuation and backscattering coefficients of the rat red blood cell (RBC) suspensions and whole blood with hematocrits ranging from 6% to 40% were measured between 30 and 60 MHz using a modified substitution approach. The acoustic parameters of porcine blood under the same conditions were also measured in order to compare differences in the blood properties between these two animals. For porcine blood, both whole blood and RBC suspension were stirred at a rotation speed of 200 rpm. Three different rotation speeds of 100, 200 and 300 rpm were carried out for rat blood experiments. The attenuation coefficients of both rat and porcine blood were found to increase linearly with frequency and hematocrit (the values of coefficients of determination (r(2)) are around 0.82-0.97 for all cases). The average attenuation coefficient of rat whole blood with a hematocrit of 40% increased from 0.26 Nepers mm(-1) at 30 MHz to 0.47 Nepers mm(-1) at 60 MHz. The maximum backscattering coefficients of both rat and porcine RBC suspensions were between 10% and 15% hematocrits at all frequencies. The fourth-power dependence of backscatter on frequency was approximately valid for rat RBC suspensions with hematocrits between 6% and 40%. However, the frequency dependence of the backscatter estimate deviates from a fourth-power law for porcine RBC suspension with hematocrit higher than 20%. The backscattering coefficient plateaued for hematocrits higher than 15% in porcine blood, but for rat blood it was maximal around a hematocrit of 20% at the same rotation speed, and shifted to a hematocrit of 10% at a higher speed. The backscattering properties of rat RBCs in plasma are similar to those of RBCs in saline at a higher rotation speed. The differences in attenuation and backscattering between rat and porcine blood may be attributed to RBCs' being smaller and the RBC aggregation level being lower for rat blood than for porcine blood.
Authors:
Chih-Chung Huang
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-09-16
Journal Detail:
Title:  Physics in medicine and biology     Volume:  55     ISSN:  1361-6560     ISO Abbreviation:  Phys Med Biol     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-22     Completed Date:  2011-01-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  5801-15     Citation Subset:  IM    
Affiliation:
Department of Electrical Engineering, Fu Jen Catholic University, Taipei, Taiwan, Republic of China. j648816n@ms23.hinet.net
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood / ultrasonography*
Erythrocyte Aggregation
Erythrocytes / cytology,  ultrasonography
Female
Hematocrit
Rats
Rotation
Species Specificity
Swine
Ultrasonics / instrumentation,  methods*

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


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