MRI Phase Encoding EXPLAINED | MRI Physics Course Lecture 4

Phase Encoding… Words that strike fear into the heart of even the most courageous of scientists, radiologists, and technologists. A topic so horrendously complex it’s best to just avoid. In fact, if you value your sanity, I’d recommend exiting this lecture and watching something more light-hearted, like cat videos. But if you’re down to get a little nerdy and crazy, we’re going to take a deep dive into this thing called phase encoding, leaving no stone unturned and by the end of it, you’ll understand exactly what it is, why we do it, and how it helps us build a picture. Welcome to MRI Physics Explained Lecture 4, Phase Encoding!

CHAPTERS:
00:00-02:48 Recap
02:48-07:06 When Only Frequency Gradient is Applied
07:06-11:00 Applying Two Gradients at the Same Time
11:00-14:25 Phase
14:25-21:29 Spatial Phase Encoding
21:29-23:41 Image Size and # of Phase Encoding Steps
23:41-27:48 How to Induce Phase Shifts
27:48-29:31 Wrap-up/Preview

Questions or suggestions for future topics? Send an email or follow Dr. TE on:
Twitter: @DrTEMD

#mri #radiology #physics #course #phase #radiologytutorial #radiologycourse

[holulu]

What is PHASE?
Imagine we are singing a song together and there are three different possible variations:

1) One of us is louder or quieter than the rest, that is a matter of Amplitude.
2) Amplitude of our voices are the same but one on us is singing faster or slower that the rest, that is a matter of Frequency.
3) Amplitude of our voices are the same (nobody is louder or quieter that the rest) and Frequency of singing are also the same (nobody is singing faster or slower the other people), but one of us is a little ahead or behind than the rest, that is a matter of PHASE (Time, but it is measured in angular degree, from zero to 360).

[Meilo]

Livesaver, i could not for the love of god figure out the phase encoding gradient like ever. After this i realised we went over phase changes back in middle school and with the help of ur vids it completed the picture for me. Will definitely recommend u to everyone studying this. ❤

[bingavtoski]

This is one of the best materials of MRI physics I have encountered. Thank you so much for your time and effort in making this.

[billyidolman]

This content is just amazing. I have spent hours upon hours watching videos on other channels and reading on websites like MRI Questions and still felt unsettled and unable to integrate the various concepts. After watching this, I feel SO MUCH better and feel I now have a solid conceptual understanding (especially understanding how the Fourier transformations help in identifying unique spatial frequencies). I wish I watched this at the start as it would have saved me such an awful headache! Thank you so much!

[MIGUELHERNANDEZ-ldfe]

Life has been good to me. This explanation has finally gotten inside my head. Excellente job doctor!

[dlo]

This was a lot to take in...I def need to watch this a couple more times for it to totally soak in. With that said this instructor is amazing

[RD]

Brilliant video describing how phase shift works, best in class.

[Mawbz]

Awesome, will be sharing this with my radiology trainee colleagues here in the UK :)
Thanks so much!

[gissellev.]

I'm taking the ARRT soon and these videos have helped me so much! I feel I finally understands the physics. Thank you for your lectures!

[stoyantodorov]

Excellent and easily apprehendable way of presenting such a complex matter, Dr. TE! Thank you very much!

[amlevi]

thank you so much for your work. To be able to explain this well you had to understand it so well yourself and then trace back the process to each logical step! impressive!

[bengoodey]

So, so, so good! Please have the T1 and T2 contrast videos asap 😊

[mateuszskrzypczyk]

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! 😎

[KokebGebremeskel]

This is truly Amazing! Thank you so much!

[DrMdAbdulHafeezMalik]

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

[Theextremepessimist]

I have to watch these videos more than once.

[aurelberger]

Thanks! Assuming we have e.g. a 100x200 pixel image in the xy-plane. Do we have to perform 100 individual measurements (with 100 different phase shifts and therefore 100 different applied gradients in the y-direction) in order to solve a 100x100 linear system of equations because we have 100 unknown amplitudes?

[globalcitizen]

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

[walaasalah]

Thanks for ur effort . Waiting for more 😅😅😅

[kt]

Like, I could get through test just by reading the class's material and memorize them, however for the life of me I couldn't figure out how the process actually works, and it bothers me greatly. Thank to your video that studying is a lot more fun for me now, since everything begins to clear up now!