22/03/2023 at 7:48 pm #48185Xue HengParticipant
Hi, Steve. Is it true that lower probe frequency has better Color Doppler sensitivity?
And what is behind this phenomenon? Thank you.
This patient had multiple myeloma, the lesion showed more Color Doppler signal with lower frenquency probe.
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22/03/2023 at 11:30 pm #48203Stephen BirdKeymaster
This case makes perfect sense to me,
If you look at the lesion you are assessing it is fairly attenuating,
If you ignore the colour Doppler and look at the B-mode characteristics the lesion is better seen with the lower frequency transducer, especially in the deeper aspect.
So if the B-mode is better with the lower frequency in the deeper parts of the lesion then the colour Doppler will also be better with lower frequency.
High frequency colour Doppler will be more sensitive in the near field, BUT lower frequency Doppler frequencies will be more sensitive at deeper depth or in more attenuative tissues.
So if you look at your case you have provided me with three different colour Doppler frequencies and the lowest frequency has won the race.
I am not surprised as the B-mode image shows it is a fairly attenuative lesion.
The high frequency colour Doppler shows excellent colour sensitivity in the near field.
The medium frequency colour Doppler shows excellent colour sensitivity in the near and medium field.
The low frequency colour Doppler shows excellent colour sensitivity right through the lesion although the pixel size is large and the spatial resolution is low.
The debate is even more complicated when you look at individual ultrasound manufacturers.
You need to know your machine !
You need to understand on your machine if colour, power, ADF, SMI, B-flow or all sorts of other algorithms are best at a particular depth.
It is very personal if you like !
So know your machine and be prepared to try lower frequency transducers if the lesion is attenuative.
Like you, you might be surprised that the best Doppler sensitivity is not where you expected to find it.
22/03/2023 at 11:52 pm #48204Xue HengParticipant
Thank you for your timely and patient answer everytime!
Steve, you really help me a lot.
23/03/2023 at 11:48 am #48219Stephen BirdKeymaster
Always a pleasure mate,
With a bit of luck I can get back to Beijing in 2024 and we can go out for a hot pot or some duck.
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