Biomaterial Database

Sizing emboli in blood using pulse Doppler ultrasound--II: Effects of beam refraction. 1996

M A Moehring, and J A Ritcey, and A Ishimaru

Institute of Applied Physiology and Medicine, Seattle, WA 98122, USA. moehring@nwlink.com

A theoretical and numerical study of the acoustic field intensity within a curved flow conduit having 1) diameter similar to the wavelength of the interrogating frequency and 2) speed of sound mismatch with the surrounding medium is presented. The field intensity is shown to vary significantly and in a monotonic fashion across the flow conduit. The resulting insonation of emboli transiting through the Doppler sample volume is explored with a Monte Carlo study of the behavior of the embolus to blood power ratio (EBR). The numerical simulation findings are shown to be in good agreement with previously reported experimental results. A method is explored for estimating embolus diameter when this refraction artifact is present, and shown to yield excellent results when applied to experimental data. Further work toward clinical application of these results is discussed.

UI	MeSH Term	Description	Entries
D007089	Image Enhancement	Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.	Image Quality Enhancement,Enhancement, Image,Enhancement, Image Quality,Enhancements, Image,Enhancements, Image Quality,Image Enhancements,Image Quality Enhancements,Quality Enhancement, Image,Quality Enhancements, Image
D007091	Image Processing, Computer-Assisted	A technique of inputting two-dimensional or three-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.	Biomedical Image Processing,Computer-Assisted Image Processing,Digital Image Processing,Image Analysis, Computer-Assisted,Image Reconstruction,Medical Image Processing,Analysis, Computer-Assisted Image,Computer-Assisted Image Analysis,Computer Assisted Image Analysis,Computer Assisted Image Processing,Computer-Assisted Image Analyses,Image Analyses, Computer-Assisted,Image Analysis, Computer Assisted,Image Processing, Biomedical,Image Processing, Computer Assisted,Image Processing, Digital,Image Processing, Medical,Image Processings, Medical,Image Reconstructions,Medical Image Processings,Processing, Biomedical Image,Processing, Digital Image,Processing, Medical Image,Processings, Digital Image,Processings, Medical Image,Reconstruction, Image,Reconstructions, Image
D008955	Models, Cardiovascular	Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.	Cardiovascular Model,Cardiovascular Models,Model, Cardiovascular
D009010	Monte Carlo Method	In statistics, a technique for numerically approximating the solution of a mathematical problem by studying the distribution of some random variable, often generated by a computer. The name alludes to the randomness characteristic of the games of chance played at the gambling casinos in Monte Carlo. (From Random House Unabridged Dictionary, 2d ed, 1993)	Method, Monte Carlo
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D004617	Embolism	Blocking of a blood vessel by an embolus which can be a blood clot or other undissolved material in the blood stream.	Embolus,Embolisms
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012212	Rheology	The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.	Flowmetry,Velocimetry,Velocimetries
D018617	Ultrasonography, Doppler, Pulsed	Ultrasonography applying the Doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return.	Doppler Ultrasonography, Pulsed,Ultrasonography, Pulsed Doppler,Doppler Pulsed Ultrasonography,Pulsed Doppler Ultrasonography,Pulsed Ultrasonography, Doppler,Ultrasonography, Doppler Pulsed
D019047	Phantoms, Imaging	Devices or objects in various imaging techniques used to visualize or enhance visualization by simulating conditions encountered in the procedure. Phantoms are used very often in procedures employing or measuring x-irradiation or radioactive material to evaluate performance. Phantoms often have properties similar to human tissue. Water demonstrates absorbing properties similar to normal tissue, hence water-filled phantoms are used to map radiation levels. Phantoms are used also as teaching aids to simulate real conditions with x-ray or ultrasonic machines. (From Iturralde, Dictionary and Handbook of Nuclear Medicine and Clinical Imaging, 1990)	Phantoms, Radiographic,Phantoms, Radiologic,Radiographic Phantoms,Radiologic Phantoms,Phantom, Radiographic,Phantom, Radiologic,Radiographic Phantom,Radiologic Phantom,Imaging Phantom,Imaging Phantoms,Phantom, Imaging