MRI T1 Relaxation & Contrast EXPLAINED | MRI Physics Course Lecture 6

T1 Recovery… Longitudinal Recovery… Spin-Lattice Interactions… Big words small people use to make you feel powerless in MRI Physics. Well no longer because on this episode of MRI Physics Explained, we’re going to demystify these subjects in a way even a baby can understand. I can’t back that claim up because kids usually run away screaming the moment they see me. But you can try it out on your children and let me know in the comments. So let’s dive deeper into the rabbit hole and finally learn the truth behind all those spinning arrows on the latest episode of MRI Physics Explained – T1 Contrast!

CHAPTERS
00:00-01:30 Intro/Recap
01:30-03:00 T1 Refresher
03:00-06:50 The Famous Animation
06:50-09:12 Something Afoul in the Physics World
09:12-12:38 The Solution
12:38-17:55 T1 Recovery Explained
17:55-22:37 T1 Contrast
22:37-26:04 Wrap-Up/Outro

Full lecture series below:

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Twitter: @DrTEMD

#mri #radiology #physics #course #t1 #contrast #radiologytutorial #radiologycourse

[joopvanbroekhoven]

I did a PhD on magnetic resonance (ESR and NMR) in 1967. MRI did not yet exist at that time. I am long retired from industry but this marvellous series is very interesting revival for me.

[Minisynapse]

As someone with (apparently) a passion for pedagogy (I'm a phd student on psychology (neuroscience actually but formally psych)), much respect for taking this kind of an approach. You delve into the topic not from the traditional "tell it like they told you" approach, but instead you use your own journey and the difficulties on your path to isolate areas where misunderstandings and confusions occur, and avoid those issues by tackling them before they even emerge. This approach is very intelligent and kind of "pre-avoids" the crucial misunderstandings you clearly know might occur when delving into MRI physics.

As much as I respect ALL educational content creators online, those who really nail the pedagogy garner the most appreciation because there's a very clear desire to help others not suffer like you did when you were learning. That is also my drive as an educator: to help others learn what I learned but not suffer as much as I did while at it...to make it easier, more enjoyable, entertaining, fascinating, intuitive.

That's how I felt watching this too. I felt like I received very important heuristics for understanding T1 and T2 imaging and all the intricacies and points of confusion that might emerge, and I feel like you nailed the fundamentals and created a solid cognitive ground on which to stand on for your viewers. You are clearly aware HOW you comprehended MRI physics and are now sharing those lessons. Beautiful!

[takauyamurengwa]

I'm grateful for your emphasis on grasping concepts, , , I had waited long for this great episode, so worth it. Looking forward to the next one

[marcochiarini]

If all my MD professor ware like you I would definitely take seriously 100% attending. Thanks a lot!

[chrisdao]

this is amazing! I've been watching a few different videos from different content creators and I love love love your videos, i especially like how you answer all of those werid silly questions because I for one sometimes get caught up on those tiny insignificant details and here you are explaining them in such an easy way. like you just said fooorget about the 63% and last week I was trying to think about the contrast i'll see at such and such times :D lol

[rik]

I love how little this focuses on the maths, which is a great point of confusion for myself. Students will get taught that the time to repetition is related to the T1 weighting because of some parameter in a formula, but it is never actually explained what the real world effect of that would look like. Great video series!

[janeabdo]

once again amazing content, thanks for making my studying easier!

[aaqibzyt]

On my only day off in a week after long ass duties i am watching these videos to understand how beautifully MRI works cuz it is so satisfying.

Finally someone is calling out random bs definitions.

[shahadab]

Thanks a lot :) one question: is the energy produced from the protons re-aligning again with the external magnetic field is basically heat energy or an RF wave or mix of both?

[nikoulei]

Great video to clear out my confusions! Thank you!

[thepirl]

Oh interesting, I hadn't considered that the animation of the of the T1/T2 relaxation vectors coming together at the same time gave the impression that they 'completed' relaxation simutaneously. That's a good catch, I'll have to fix that animation on those slides for future talks. Brilliant series mate! Cheers

[Quazlyy]

Thank you for this amazing video series! I really helped me prepare for my MRI related Master's thesis.
One note about the 63%. It's not as arbitrary as one might think. This definition allows us to write the relaxation curve as (1-e^(-t/T1)) (I'm disregarding some scaling factors here).
If we plug in t=T1, we get 1-1/e, which is approximately 63%. The choice of the base 'e' could be seen as arbitrary, but it is quite natural in my opinion.
The same argument can be made for T2 with 37%.

[taytwimming]

Got my MRI physics exam tomorrow 😂😂😂
You‘re a life-saver!
Greetings from Germany

[jakobthomsen]

Very well explained!
BTW the 63% looks suspiciously like 1-exp(-1)

[canerozturk]

I didn't really understand one point about T1 signal. Why the second RF pulse gets us the signal from only the fully recovered portion of the longitudinal relaxation? Why doesn't it resets the situation to full transverse magnetisation? I thought the 90 degree RF pulse affected all protons in the area and excite them into transverse magnetisation.

[amlevi]

can't wait for next lecture! to bad my DWI and perfusion tecniques exam is two weeks from now! :D

[pantrywarriors]

I am a bit confused, does T1 itself contribute to the image? Does the literal physical process of T1 recovery induce a current in the coils?

[tomways]

Struggling a bit here. Could you tell me why bone has a longer net-magnetisation relaxation time than CSF? Since CSF has more water molecules, therefore higher proton numbers, why does bone take longer when it has less of everything mentioned above? Shouldn't the more protons = longer time for them to relax? Yet bone has less and takes longer? This is why I'm confused, thanks.