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Re: Physics of Ultrasound From: Terry J DuBose (tjdubose@juno.com) Tue Oct 2 07:53:20 2001 Messages sorted by: [ date ][ thread ][ subject ][ author ] Next message: udaya kumar: "Re: Physics of Ultrasound" Previous message: Wolfgang Moroder, MD: "Physics of Ultrasound" Maybe in reply to: Wolfgang Moroder, MD: "Physics of Ultrasound" Next in thread: Wolfgang Moroder, MD: "Re: Physics of Ultrasound" Reply: Wolfgang Moroder, MD: "Re: Physics of Ultrasound" Dr. Moroder, what you describe sounds like a phenomenon known as "streaming", or a "force effect". Adrian Anthony describes it in DuBose, FETAL SONOGRAPHY, Chapter 3: Biological Effects and Safety. He states: " These radiation forces, categorized with names such as the alternating force, radiation torque, acoustic streaming, Stokes force, the Oseen force and the Bernoulli force, can occur in liquid-like media." It is due to the acoustic pressure, impedances, and proprogation through the medium. I would think eddying in fluids due to heat would mean the heated particles would rise, rather than moving away from the transducer... assuming the transducer is not below the liquid. As for the content, a hemorrhagic endometrioma (which you suggested) at some stage of becoming a "chocolate cyst" might have the appropriate viscosity and particulate matter to demonstrate this. This is interesting, I have read about the phenomena, but have never personally witnessed it. If you could either submit a brief digitized video clip, or a color image showing the "blush" I would very much like to see it.... Thanks, Terry J DuBose, M.S., RDMS, APS ------------------------------------------------ On Tue, 2 Oct 2001 02:01:18 -0500 womorode@tin.it (Wolfgang Moroder, MD) ------------------------------------------------ writes: ------------------------------------------------ > Scanning a 9 cm large pelvic cyst with a diffuse fine moderatly echogenic content (endometriosis?) I observed, for the first time, a phenomenon of the small particles moving constantly away from the 7 MHz TV probe. I could even measure the speed impressed which was aroud 0.3 cm/s. With color it was more evident with a "blush" showing that the particles were accelerated by the approach of the probe. Now, my question is if it is the heat or the mechanical action of the ultrasound which impresses the movement to the particles? What kind of content (particles) could show such a phenomenon and finally if this could have some diagnostic value for the nature ot the cyst? > -- > Wolfgang Moroder, MD > Prenatal Unit > Bolzano General Hospital Italy Next message: udaya kumar: "Re: Physics of Ultrasound" Previous message: Wolfgang Moroder, MD: "Physics of Ultrasound" Maybe in reply to: Wolfgang Moroder, MD: "Physics of Ultrasound" Next in thread: Wolfgang Moroder, MD: "Re: Physics of Ultrasound" Reply: Wolfgang Moroder, MD: "Re: Physics of Ultrasound"

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