MRI - CONCATENATIONS - BACK TO BASIC

Рет қаралды 12,722

Күн бұрын

Concatenations can be difficult to understand, but yet another important parameter. This parameter is not only for the image quality, but also for the scan time reduction. I hope this video will give you a better understanding of what it is.
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Пікірлер: 65

@moneeb343 Жыл бұрын

These "Back To Basic" series are so so sooooo good! Thank you!

@DrunkenViet Жыл бұрын

thank you for this! as a newbie tech, your explanations are simple and clear. Please keep coming up with more content. I'd love to see a video on phase encoding and FOV phase concepts.

@iansze2652 Жыл бұрын

It's always best practice when you require more slices for coverage, ALWAYS do a final check of your parameters to ensure your weightings are still within range (i.e. T1, T2, PD), as adding slices will always affect TR times.

@Lethmyr_ Жыл бұрын

Thanks :) Could you do a video about turbo factor? How to use it efficiently and optimal TFs for different sequences? T1, T2, STIR, PD?

@dr.magnet9033 Жыл бұрын

thank you, before this video I did not know how to use these parameters correctly.

@vivianetoledovts Жыл бұрын

Wow! That’s really great! Thank you! I didn’t know about the “crosstalk” artifacts.

@Pimon8188 Жыл бұрын

Again a great video! And very important to also talk about the basics. Thanks so much for this valuable content!

@anniesshenanigans3815 Жыл бұрын

I definitely use it. I didn't know about the zero gap !! Thanks!!

@MRI197 Жыл бұрын

This was very helpful thank you!! Keeping putting out these videos please love watching them to learn and refresh the important stuff!!

@fraanmendieta Жыл бұрын

great video! i will try it at work this week and see how it goes

@leggyReid4c 10 ай бұрын

Here taking notes. Thank you , thank you.

@LilCash217 Жыл бұрын

Can you make a video on TR values for each sequence on 3t. Etc the min and max tr for pdfs, t1,t2…. Thank you

@mina2306 Жыл бұрын

Very useful video , tnx.

@philiplledo2510 Жыл бұрын

Very informative. Thanks

@hunnymun1 5 ай бұрын

I used cancet. when I scan t1 post contrast study many times. When there is SAR issue, TR increases like over than 1000, then I needed to decreased TR to keep the TR contrast for t1 images by increasing cancetenation. but thanks for the idea bet relationship bet. cancat and gap factor. 👍

@Nguyen_MRI 5 ай бұрын

thanks for your input :)

@bassamalameri8804 Жыл бұрын

ماشاء الله تبارك الله ♥

@SonaRezadoust 9 ай бұрын

i use concatenation when i have very long breath hold in abdominal examinations

@Nguyen_MRI 9 ай бұрын

Yes good choice.

@SUJITHARADTECH-wo2od Жыл бұрын

What is the difference between averages and concatenation?

@mihaimoldo Жыл бұрын

Great video Bac. You get used to concats pretty early on if you read anything about TR , however I didn't consider to use it when doing 0 gap sequences , even though it makes sense and you would think it's a solution to cross talk readily at hand, I never checked if the sequence has 1 concat or 2. You've given us a new simple trick to use in our daily routine . Thanks ! Btw some books refer to the 0 slice gap as cross excitation and reserve the cross talk artifact for multi slice groups overlapping such as the Lumbar Axials where the slice group cross each other . Same artifact ofc but in practice cross excitation is usually very subtle while cross talk is a black band easily detected . Maybe it's a pedantic distinction but I find it useful in practice .

@Nguyen_MRI Жыл бұрын

Yeah very much agreed. ☺️

@mihaimoldo Жыл бұрын

@@Nguyen_MRI forgot to add one bonus of using more than 1 concat in Siemens at least is that you can see in Inline Display Tab half of the images acquired , when 1 concat is done, this allows you to check if the pacient is moving before the sequence is completed in total . For example , if your sequence is 4 min and has 2 concatenations , after 1 concat is done you can see at the minute 2 mark half of the images acquired , so if the pacient moves considerably you can stop the sequence and not waste 2 more minutes for nothing .

@Nguyen_MRI Жыл бұрын

@@mihaimoldo yeah a big bonus. But sometimes it just doesn’t show. I’m not sure why it does and another it doesn’t. 🧐

@mihaimoldo Жыл бұрын

@@Nguyen_MRI most likely a software bug.

@Nguyen_MRI Жыл бұрын

@@mihaimoldo I keep wishing so but I’ve seen this across old to newest software 😂. It’s awesome when it works though.

@Nguyen_MRI Жыл бұрын

Is this a parameter you have in mind in your daily work?

@brahimmb5495 Жыл бұрын

Yes thanks 🙏

@dvalled18 Жыл бұрын

Of course! And also the turbo factor is another important parameter to adjust the TR and the acquisition time...

@mirelamihaila1884 Жыл бұрын

Hey. I found your videos so helpfull especially those back tot basic, could you please do a video about the Pd, T1, T2 ranges. Thank you și much!

@aruizglz Жыл бұрын

Debería traducir al español. Gracias

@selimakko9811 Жыл бұрын

👍🏻

@sajidali-pq6ws Жыл бұрын

Hi Bac... Great video as usual.... My question is Siemens Magnetom-c open MRI dixon swap method please...

@Ifeanyi736 7 ай бұрын

Great video! Can you describe in a nutshell how the distant factor affect or causes cross talk.? I didn't get that part properly. Thanks

@Nguyen_MRI 7 ай бұрын

mriquestions.com/cross-talk.html

@orcaartist Жыл бұрын

I also increase concats when dealing with some breath-hold sequences as it will drop the breath-hold time but increase the scan time. Can you please do a video covering distance factor and cross talk? That’s new to me.

@Nguyen_MRI Жыл бұрын

Hi. Here you go. kzfaq.info/get/bejne/iNaXjcSJxtmad30.html

@alisuleiman3069 Жыл бұрын

I would to Thank you a lot for your help But can I ask you how to you use the respiratory trigger correctly on siemens Cause I can't active it by physico

@Nguyen_MRI Жыл бұрын

It depends on sequences. Some are possible others not.

@weweali6 Жыл бұрын

Hi sir how are u thanks for your nice videos plz in which software version can we find DRB in Siemens mri Thanks

@Nguyen_MRI Жыл бұрын

More info here: www.siemens-healthineers.com/no/magnetic-resonance-imaging/options-and-upgrades/clinical-applications/deep-resolve-boost

@weweali6 Жыл бұрын

Very thank sir

@bboydoctor Жыл бұрын

Hi Bac, the cross talk artifact should be minimized, even with one concatenation and no distance factor, by choosing the interleaved excitation mode. Can you confirm that?

@Nguyen_MRI Жыл бұрын

hi marco, very interesting question you ask here. the sequences are done with interleaved excitation mode. what is your experience regarding this relationship of distance factor - concats - crosstalk?

@bboydoctor Жыл бұрын

Actually I never tried to compare sequences to check if cross talk causes a reduction of the average signal because if we excite even slices first and then the odd ones, I don't see how the artifact can occur. But if you tell me that in your experiment you used the interleaved mode the it means that it does occur anyway. One thing that I pay attention to when I don't use distant factor is to use a normal or low SAR RF pulse type to have a sharper slice profile.

@Nguyen_MRI Жыл бұрын

@@bboydoctor interesting. 👍

@samuelpistis Жыл бұрын

I agree. Selectively exciting even slice profiles before odd ones solves the conundrum.

@reemsuwan7483 Жыл бұрын

Hi .can you please give us about adabatic pulse

@Nguyen_MRI Жыл бұрын

mriquestions.com/adiabatic-pulses.html

@23232Bing Жыл бұрын

Do you use a concatenations of 2 in STIR sequences? I heard that the lower the TR the better the suppression it would be.

@Nguyen_MRI Жыл бұрын

I use the same approach for stir. However, lower the tr for better fat suppression is new to me. I carefully control the TI for optimal fat suppression though. Interesting.

@mihaimoldo Жыл бұрын

Doesn't make any sense since your TI time is directly related to the TR. There's also a freeze suppress tissue option next the TI so it automatically changes the TI if you change the TR. STIR by definition has homogeneous fat suppression due to numerous 180° inversion pulses, thats why it was the first fat suppression technique used in the first lower fields MRIs, sadly it's susceptibile to motion and pulsation artifacts . But in newer machines especially higher fields like 3T , normal Fat sat or Dixon is preferred due to being faster and less SAR (especially important at 3T) technique .

@23232Bing Жыл бұрын

@@mihaimoldo I only used the freeze option in flair. I have never heard this for stir.

@mihaimoldo Жыл бұрын

@@23232Bing yeah it's rarely used in STIR . in FLAIR however is used because the TR is lower than the TR necessary for the liquid true T1 time , since the calculation is 5x T1 of the tissue for IR, that would make it in reality 15000 TR, when in most it's kept at 9000 due to time constraints . However lowering the TR in STIR for a better suppression makes no sense . Making it higher than the minimum required is what many do, the higher the TR the more signal , but ofc higher acquisition time . That's why in siemens a T2 spine STIR has higher TR than the minimum required for those nr of slices.

@Nguyen_MRI Жыл бұрын

It’s a bit funny because stir is one of the oldest fat suppression technique, the very first thing you read and learn. it seems easy to understand, but yet it keep surprising me through the years. 😂👍. Nevertheless, old but still powerful for certain things.

@aleiatar Жыл бұрын

Hi Bac, great video as usual! I have a question about the TR in T1 sequences... In your opinion which is the TR range of a T1 on a 3T. I used to put the limit at 800ms and 900ms in case of a fat sat.

@Nguyen_MRI Жыл бұрын

Same here as you do.