Doppler Ultrasound - Science topic

it is nice subject

NO!!!! Systolic pulse can be altered in many situation, not only in hyperthyroidism. Hashimoto's thyroiditis is most frequently associated with hypothyroidism, but we must not forget that "hashitoxicosis" does occur too.

Please see attached files. I have used Scilab5.3.3 instead of Matlab. Scilab5.3.3 It is freely downloadable.The equations you can modify/ add and change once you are familiar with the code. I just plotted abs value of the signal.in pdf

Hope you find it useful

Good Luck

Cheers

Federico,

If you are interested in flow volume, yes, the systolic diameter is the significant one, as most of flow occurs during the systolic phase. Accurate absolute flow volume, however, is rarely of clinical interest: person-to-person variation, as well as the impedance of the vasculature, varies so much that there is no "correct" volume flow like 37C for temperature. What is generally clinically significant are  gross changes, e.g. no flow indicating a blockage, or high flow indicating a hemorrhage, or relative changes, e.g. change in cerebral flow while holding your breath.

Various methods have been proposed for determining the lumen. One method that is appealing to engineers, is to use a narrow beam, and then a beam wide enough to ensure full insonation of the vessel, and look at the difference in backscattered energy at the same distance (so the attenuation is the same); if you know the diameter of the narrow beam, the ratio of the wide to narrow backscatter energy times the diameter of the narrow beam gives the lumen cross-section. (To do this right you must take into account the non-uniformities of the beams, so its not so simple -- or often used.)

See David Evans's publications for real expertise in this and other areas of transcranial Doppler measurements.

Regards,

David

I would defintely recommend you visit www.MIPAR.us.

It is very powerful and intuitive 2D/3D image analysis software written by scientists/end-users and is about to be released as a free trial on December 14th. You can sign up on the site as well as submit images/datasets to test.

There are many image analysis options available, but I think you may just find MIPAR to be something special if you give it a try!

You may use X-Ray customed to rats from barintree company for detecting objects noninvasively.

Inflammation has some changes in CBC test which increase the Luekucytes (granulated).

yes

Correct! There is no angle guidance.

But AUD should be performed on the booth side it is more than important and recommanded to observe other parameters such umb. art.  and DVPI.

There is not enough evidence (as yet) that TCD is useful or gives us meaningful information. TCD is probably more useful in intra-cerebral haemorrhage but again, not enough information as yet

No difference if they are traveling at the same speed. May be the signal strngth could be different.

In my opinion DV is not helpfull as isolated Dopplerparameter. The old fashioned idea of an step to step change of UA > MCA > DV seems to be not true (Unterscheider J et al. AJOG 2013 539e1) . There are multiple combinations of changes in the Doppler Parameters and we have to check the follow up of all of them including growth, Amnion Fluid, BPP and the cerebro placental ratio.

DV is sometimes difficult to measure in a IUGR Fetus an there is a risk for a false positive "reversed flow" by measuring the liver vessels. You need training and supervison.

as far as i remember both can be considerdd as markers of local and global conditions, i caucasic population there is not much difference. In asia this may differ,

Surrogate sonographic markers of atherosclerosis.

Abbas MA, Corea F. Stroke. 2006 Jul;37(7):1644; author reply 1645. Epub 2006 Jun 1.

Jakub:

There is one other example of a change in density of a fluid causing ultrasound echoes on both B-Mode and Color Doppler Modes that I am aware of: ureteral jets. When performing an US of the bladder trigone, jets of urine entering from the ureters can be identified. This effect is even more apparent on color doppler, which is interesting as I believe that the color doppler phenomenon relies on red blood cell movement in relation to the ultrasound probe. Prior studies examining the finding of ureteral jets have theorized that a difference in density between the urine in the ureter and the urine in the bladder is responsible for the US appearance. So my guess regarding what you observed with your experiment was that the NaCl was not contaminated, but rather the interaction between different densities of saline resulted in the ultrasonographic findings.

I hope that helps

Ralph