How MRI Works - Part 4 - The Gradient Recalled Echo (GRE)

How MRI Works - Part 4 - The Gradient Recalled Echo (GRE) MRI Sequence

Powerpoint slides from this lecture can be purchased here:

0:00 - Intro
1:07 - NMR Review
2:14 - Laboratory/Rotating Reference Frames
4:18 - The Gradient Echo
7:28 - GRE Overview
10:52 - Scanner: B0 Magnet
12:57 - Scanner: Gradient Coils
16:45 - Scanner: RF Coil
19:23 - Slice Selection
26:46 - The Signal Equation
29:17 - Frequency Encoding
32:56 - Phase Encoding
36:20 - k-Space and Gradients
44:19 - k-Space and Signal
48:30 - The Gradient Recalled Echo Sequence
52:06 - Phase vs Frequency Encoding
55:42 - Echo Planar Imaging
56:23 - GRE Exercise and Outro

[thepirl]

Error Corrections and clarifications:
1:22 - When we morph the many spins into one M vector, the animation shows M precessing about B. If the spins are in equilibrium then M would be colinear with B and no precession would be occuring, but here I animate as if our spin sample had just experienced excitation and thus M and B are not aligned allowing for precession - defnintely not clear in the video (thanks to @SCramah13!)
20:19 - Δω is not 42.578 kHz, it's 4.2578 kHz (thanks to @johnclarky4375 for catching this!)
36:06 - My labels for 'phase encoding' and 'frequency encoding' are swapped. (thanks to @timangoes for this one!)

[brucevanbeek]

I am here because my son is in MRI ! At a university.
So, to understand his passion .
I'm learning from these videos. The language and understanding of MRI.
Thank you .
🎉

[CollinKeegan]

Genuinely amazing how much commitment you have to finishing such an insanely high quality, detailed, easy to understand explanation on a relatively obscure topic. This is, across all sorts of topics, really one of the best YouTube channels I've ever seen for explaining complex topics in an understandable way.

[zyplocs]

The greatest video series I've ever seen. Your animations and eloquent explanations are out of this world! If you happen to make a follow-up, I'd love to see discussions of fMRI and BOLD analysis, since these are my areas of application. Cheers!

[Frofelfel]

Thanks ! It's fantastic you are still completing this series after years...looking forward to more from you

[someonesomeone]

omg dude you are a legend. My journey with your channel started as I was a med student interested in spin dynamics, now I am a noob radiologist and just recently starting to work with MRI, you can not imagine how happy it made to see this video in notifications. Your videos are best explanation to MRI physics anywhere on internet, I just love it!

[lordtopkek]

You Sir, are a Scholar and a Gentleman!

[valentirodonfont]

Arguably, one of the best (if not THE best) Educational Series I have ever seen in my entire + 50 life and BSc Industrial Engineering background.

Its painstaking attention to detail, the beauty and virtuosity in all the curated visuals, its deep-dive yet easy-to-understand explanations... a top-level Educational Masterpiece, in a word.

My sincerest congratulations and admiration thus to the generous and talented Artist behind this Series. Just can't wait for the next one!

[普羅米修斯-um]

this video is a fantastic for anyone interested in learning about MRI technology. Great work!

[TEMMIE-huuz]

Your series on MRI is absolutely brilliant, and this episode in particular is especially amazing considering the depth you go into whilst maintaining a clear and coherent train of thought. So happy to see you still uploading :D

[Blueyzachary]

Yooo I immediately thought of string art being like CT scanners

[MRIPhysicsEXPLAINED]

Top notch lecture, one of the best out there on K-Space and image formation!

[thelosc]

I am really looking forward to MRI part 5. All the possible topics you mentioned at the end sound fascinating!

[matejnastran]

Thank you for this wonderful series. I hope to see more from you. I loved how you didn't simply neglect the physical coil design.

[lopzag]

Incredible video, really impressed by the clarity of explanation.

[je_tai]

You are an absolute genius in vulgarization and on top of it you are extremely talented for making animations which help tremendously in the visualization and understanding of such advanced subjects. Thank you so much for continuing this series of video after the years.

[seekingtruth]

Amazing! The best video for MRI introduction on YouTube.

[vma]

Quality and detail are INSANE! Thanks so much for sharing

[Runwithmelika]

You are a legend! I just started my new job as an MRI data analyst, and I absolutely love your videos—they're amazing! I’m currently creating an onboarding document for future employees and students in our group, and your videos will be at the top of the list for everyone to learn MRI easily. Thank you, thank you so much for creating such awesome content!

[劉家宇-zf]

This is so far the best MRI lecture I have ever found. I am a first year resident in radiology and have been struggling to understand the complicated concept in MRI for a long time. These fantastic videos really helps me out! Thanks a lot dude!