Re: Physics of Ultrasound
From: Wolfgang Moroder, MD (womorode@tin.it)
Wed Oct 3 04:25:00 2001
Thank you Terry for the valuable information, unfortunately I cannot
send you a clip and the color picture somehow disappeared. The patient
is scheduled for surgery and I'll scan her again, send you a pic and the
histology. Regards Wolfgang.
At Tue, 2 Oct 2001, Terry J DuBose wrote:
>
>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
--
Wolfgang Moroder, MD
Prenatal Unit
Bolzano General Hospital Italy
|
|
