Great video series! Ok, so if I understand correctly the magnetization recovery process can be described (omitting constants) by a differential equation f'(t)=1-f(t) where t is time, f'(t) is the re-magnetization rate which is proportional to 1-f(t) i.e. the difference missing to "fully magnetized", where f(t) is the current magnetization proportion (1 meaning 100% magnetized). Because the constant 1 vanishes when taking the derivative f'(t) must be -f(t) which means it must be the exponential function with negative exponent: f'(t) = -e^-t and f(t) = e^-t, because the exponential function is the only function that is its own derivative. And to account for the re-magnetization speed or respectively the re-magnetization time we introduce a scaling factor 1/T1. Which gives us the full formula 1 - e^(-t/T1). And because this function approaches 1 i.e. full re-magnetization only in the limit t -> infinity, we choose some finite time instead. With t/T1 = 0 meaning full de-magnetization the next obvious choice is to choose t/T1 = 1 i.e. t = T1 which gives us 1-e^-1 = 1-0.37 = 0.63 approximately. Phew, I think I got the math part 🙂

Thanks

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

Great video.. you made it super interesting to learn, thank you!

STRONG WORK. Thank you

It was easiest explanation I have encountered till now ,Plz post more videos

Thank you y

LINK TO CLINICAL FLOW CHART 👇👇👇 radiofreedia.org/approach-to-abnormal-restricted-diffusion/

Local AM radio stations operate between 540 and 1700 kHz, not 68 MHz. FM radio stations operate between 88 and 108 MHz which is slightly higher than your example of a 1.5T magnetic field.

Waiting for more videos.Excellent explanation.

This is truly Amazing! Thank you so much!

that was good

Question: how were we able to localize in the Z-X plane before when we were also using gradient magnetic fields in both these axes?

As an MRI Field Service Engineer, it is my job to ensure that all the intricate MRI Physics are functioning properly every day. I'm grateful for the "MRI Physics EXPLAINED" channel on KZbin, now I can direct people with questions to this resource. Your efforts are much appreciated, please continue to create valuable content.

Hello, Great job👍💯. I have developed a new methodoloy to do Wavelet Transform, Uncertainty Principle Graph, X-rays..... I have wrote about it. These theories you can use in Quantum Physics: And with these theories I haved solved Prime Numbers and Riemann's Hypotesis. It applies to MRI... kzbin.info/www/bejne/pZO0oYWwpamsiKMsi=Fb0fiSavner-XHER kzbin.info/www/bejne/e2q3d6Vnh7Gge6Msi=b4FTZxePO7kChF8- kzbin.info/www/bejne/jpWbh2yJiZaFesksi=hEZSejrw5V6Yk-mB kzbin.info/www/bejne/pmG9lGylo7CEZrMsi=nb0yLS3_CoLnRS6L kzbin.info/www/bejne/aXbFp6ymn5pqbacsi=7iiGMVKOcnQlXiIo www.amazon.com/s?k=jos%C3%A9+mauricio+orellana+d%C3%ADaz&crid=9Y4AJXKYABD3&sprefix=Jos%C3%A9+maur%2Caps%2C294&ref=nb_sb_ss_ts-doa-p_1_9

LINK TO CLINICAL FLOW CHART 👇👇👇 radiofreedia.org/approach-to-abnormal-restricted-diffusion/

Thank you, I appreciate your pedagogy and humor!!🧠😂💯 KEEP IT GOING!!!

Why is it called "planar"?

Great job 👏

You're a genius! thank you so much

lol ceo jocks

Hospital finances are important for the CEO LOL your hilarious 🤣 😂

Thank you so much, can you lecture on the parameters: fov, matrix and tr that influence time?

Great. Thank you!

Hello from Kazan, Russia! Big thanks for your videos!!!

Amazing!!! Best MRI lectures on KZbin!

Your lectures are the best on KZbin yet. Thanks a million!

🎉🎉🎉 thanks. It's very understandable. Could we have video about Steady state, Mister?

Your videos are awesome!!

Thanks so much. 🎉 I have some stuck with this kind of knowledge. I have been reading many lectures about MRI. Could I ask you some question, Mister? 1. Some of people said that: The flip angle is determined by proportion of spin state "up and down" after exciting pulse. Is that correct? 2. After 90 RF pulse, a number of spin up will be equal to spin down. The spins which is resonated will be in phase. It is explained by quantumn machenics. But it seems to confuse me. Maybe is there something force them to be in phase? Also I don't know why 180 RF pulse cause it too. Somewhere in the internet, they explained understandably in the vector frame that the fast spin will catch up the lag spin and despend on the direction you put 180 pulse in. But when i try to apply it into the picture of spin-state, it makes me impossible to understand. 3. About 180 RF pulse in spin echo, after 90 exciting pulse, the transverse magnetization will gain conherence a little bit then dephasing with T2* decay. When we do a series of another 180 RF pulse, we have some coherence peaks. However, they gradually descrease magnitude and when we connect these peaks, we have T2 Decay. What make these peaks become smaller and smaller after 180 RF pulses. 4. After 90 RF pulse, we add a RF 180F Pulse. Now the vector B1 maybe >180? Is that mean the more spin up state becomes spin down? Could you do me a favor? 😭 I stuck with these problems a few days.

Probably one of the best mr teachers out there. Thanks so much dude.

Excellent

lettice

Amazing lecture. Thanks so much!!!

Hell yeah, been waiting for a DWI video 🙏

You have made understanding MR Physics so easy! Your sense of humour is icing on the cake. Feeling confident taking the ARRT after watching your videos. Thank you so much!

My only regret is not starting my MRI training later so that I have all your videos to watch. You're a legend!

I have watched several videos and read material from various sources on phase encoding. Your content has been the easiest to comprehend which otherwise is a challenging topic. The other sources either don't go into much detail or they go too much into the weeds. You have kept it simple with good animation and even the math has been simplified so it is easy to understand. I commend and appreciate your efforts, your knowledge and presentation skills. Quick question - do you plan on doing a presentation on Receive Bandwidth, sampling time, relation to frequency FOV, Nyquist theorm etc. Oh, and K space too :D

Thanks for this! I noticed at 6:23 in video you discussing spinning after RF pulse, wouldn't they be "wobbling" around a vector pointed in the y-xis? As opposed to circling all the way around like that? Sorry probably dumb question

I'm working my way through these lectures and it's insane to me we still haven't arrived at k-space yet. My teacher started working with k-space at lecture 1 about 1D MRI...

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!

Nice really helpful

It's a shame that channel like this, get this many views, while "educational" videos in this subject get way more. Finally understood the situation fully before Medical Imaging Techniques retake exams. Keep up the good work doc! 😎

Okay so question. If we do frequency encoding with a gradient like this. When we go to measure our FT’es signals like at 7:36. We are looking for a difference in amplitude as our contrast. Ideally this difference in amplitude comes from T1 or T2 depending on what sequence we have set up. But here the difference in amplitude is also coming from the fact that we are measuring waves with two different frequencies at the same time point. I.E at 7:36 we are measuring the peak of Fat but not the peak of CSF. So our contrast is slightly influenced by how strong our Gx gradient is.

Slice thickness = frequency range Good.

Amazing 🎉😮

Been waiting for this, thank you!