Magnetic Resonance Imaging
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- čas přidán 2. 08. 2024
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Correction: At 3 mins 09 seconds it should be "it will precess in a magnetic field" not "it will spin". Sorry about that.
In this video I explain how magnetic resonance imagining works.
Background by www.123FreeVectors.com
#physics #science #education
0:00 Intro & History
0:57 Simple Explanation
2:34 Detailed Explanation
5:02 Equations and Figures
7:08 Summary
7:33 Spatial Resolution
8:11 Health Risks
9:19 Sponsor Message - Věda a technologie
Special Black Friday deal! Every purchase of a 2-year plan will get you 4 additional months free. Go to nordvpn.org/sabine and use our coupon sabine at checkout.
I already have Nord VPN it's great.. You have a great accent! Thank you for the science.
Do you know Pierre Robitaille?
Video 41 minutes earlier, pinned 1 day earlier. I bet very elite views came first
New follower here. Love your videos!!!
I wish to find someone to explain to me the mathematical explanation of the equation that Micho Kaku wrote in this Video(Lagrangian), how he got an infinity from the equation step by step and why he wrote infinitife +infinitife +.......
czcams.com/video/4Y6OT0QXIAw/video.html
Been enjoying this channel for months now but came to all previous topics as a n00b, finally I am on familiar ground (PhD in MRI) and it's still just as great and educational.
Fancy seeing you here! 😷
Great to see you here!
@@SabineHossenfelder Who, me or Dr. Francis? 😜
And how did you end upp to work as a ninja?
As an organic chemist 1H- and 13C NMR is a pretty useful analytical tool. And I have over the years made several attempts to sit down and learn the theoretical framework as well as the practical application. But it seems like I'm about as useful as a rock in this department. It does not compute. Chromatography seems to be the limit for me to figure out. So I will continue to give the analyst my sample and quietly observe when they perform their voodoo.
What a coincidence! I had my MRI scan today morning for my absence seizure illnesses. While I was having my scan, I was thinking to know more about MRI. And here my favourite physicists is explaining about MRI. Thanks a lot 😊
Kind of spooky how she manages to time all these just when we need them, isn't it?
Wah... Wah...
This is quickly becoming one of my favourite channel
Same for me
Same
It already is mine. Easily the best science channel.
Why is this so underrated? Every time I discover one of the older Sabine-videos, I 'm astonished how good they are. All the best for the team.
This nice video brings me some nostalgy, as it takes me to mid-80th and times of my thesis as a young computational physicist. While NMR spectroscopy was already a well-established tool in analytical chemistry and biology, MRI was still in its infancy and a challenge for research in many directions. Modern MRI is a beautiful chain of advanced methods which go _much beyond_ the level presented in this short introductory video. Yet creation of very strong and extremely homogeneous magnetic fields, necessary for MRI, has been a huge topic of research for several decades. So very sophisticated and highly optimized gradient coils, shim coils, rf-coils. From other indispensable components of MRI methodology, mention at least vast domain of Fast Fourier Transformation, image reconstruction from projections, strong signal suppression techniques, etc etc. Dozens and dozens of excellent physicists, chemists and engineers contributed to MRI in its modern advanced form, which revolutionized medical diagnostics. Think about them, when passing a MRI scan in a hospital...
Sabine, I have worked building test stations to simulate MRI machines to test medical implantable devices and have heard many explanations of how MRI works. So far your explanation is the simplest and best. Thanks!
A brain cancer patient, I'm all too familiar with MRI scans. This is far and away the best explanation I've found for how a scan works, thank you!
Great explanation how NMR spectroscopy works. Thanks.
I keep reading MRI studies trying to understand how exactly this works. Happy to have a physicist it explaining in plain humanese.
This is my area, I have a PhD in this. I have a some MR images o my channel
@@mrwideboy My greetings dear fellow. PhD in psychoacoustics here. (how on earth do you make this work and how do you make sense out of it???)
@@chrissidiras I takes a while! But if you know how to calculate the spin operators ita not that bad. Starting off with NMR first and seeing the FID helps to see what is going on. It then take a a little while to get you hears around K space imaging. My area is diffusion NMR
@@chrissidiras how donyou make what work? Psychoacoustics?
@@leif1075 If I get it correctly you are asking what psychoacoustics is. It's a branch of neuropsychology concering audition on the behavioral level, that is perception of sound.
Excellent as usual. Applied physics is so much more interesting than Dark Matter
You have a point ;)
Not, if you count even Dart Wader.
All applied physics starts out as theoretical. Personally, I can't wait for applications that come from understanding dark matter and/or energy.
Is dark matter a sinking theory?
@@greeceuranusputin
Not necessarily.
.
It can do, but e.g. classical thermodynamics started off in industry and then spread to theorists.
.
Also, I suspect any direct applications of dark matter or energy won't happen in your lifetime.
I did my PhD in NMR spectroscopy which pre-dates MRI. Spectroscopy does not apply a magnetic field gradient to locate and map the nuclei in space. It uses the fact that nearby nuclei and electrons in a molecule alter the applied magnetic field at a given nucleus by a very small amount, measured in parts per million (ppm) of the applied field. So the Larmor frequency of the nuclei also vary from place to place in the molecule by frequency differences of ppm.
This means that a graph can be drawn where peaks of different intensities appear in different places along a horizontal frequency axis. The exact frequency of a peak depends of the location of the nucleus within the molecule. Signals differentiated by frequency comprise a spectrum, like a rainbow is a spectrum of different light frequencies or colours. From these graphs, the structure of the molecule can be deduced.
These days large molecules such as proteins can be studied and also interactions with other molecules such as drugs. Instead of just a single frequency dimension graph, two or higher dimensions may be looked at.
I've had an MRI once. I was impressed by the machine and what science and R&D must've gone into those machines. Now I'm even more impressed. Thanks!
Sabine, I adore you and your sharp clarity and amazing mind.
Brilliant as usual - from a physician here 👏👏👏 thanks Sabine!
Thanks!
@@SabineHossenfelder please let me know should you need any advice when it comes to medical topics - I have a huge interest in Physics and would love to collaborate with you - I practice in the U.S. and you can easily find me on LinkedIn. Keep the great work!
I always learn new things here, understand better, and enjoy more.
1M thanks, Sabine!
you are amazing 🌸
Thanks, happy to be useful!
Thank you for bringing up this topic. This is the very fundamental subject for medical physics students or biomedical engineering students which is a very difficult one.
Nice vid Sabine! We were always working in the rotating frame in my atomic phys course so I never go to see nice full solutions like those animations you had here, and T1 & T2 were defined but didnt make as much sense as how you described them here. Thanks!
Thank you for the clear explanation of the inner working of an MRI scanner. Those machines have improved an order of magnitude (and more) in the definition of the imaging thanks to the much improved hardware and software; the very first commercial MRI used a 80286 processor! The only other way to improve definition, as you have shown with the formula, is to use a stronger permanent magnetic field; from the top of my head, cheaper or older scanners use a 1.5 T magnet, while top line machines are 3 T.
I'm a pragmatic science follower, I have taken MRI scans, but I have an unexplained hunch feeling against the exposure to such strong magnetic field for half hour at time.
Regardless of my feelings, MRI machines have advanced the medical diagnostic science in unparalleled ways, allowing otherwise impossible diagnosis.
Thanks once more, and regards from lockdown UK...
Detailed explanation Mrs.Sabine , thank you
I have meant to look into this for several years, nice clear explanation (as always). Thanks
If this applied physics video becomes a series on different topics could very well become a cult.
Very good content.
A wet dream: a collaboration with Ben Krasnow from Applied Science
Dr Hossenfelder (Sabine?), I have to say I have taken many courses which touched on this topic, from advanced chemistry to radiation biophysics and medicine... and this video was by far one of the most helpful explanations I have ever seen. You could do an entire season of these and I wouldn't miss a second of it. Keep up the good work!
I just wanted to say, this is a better, clearer (and more concise!) explanation of NMR/MRI technology and science than I received either in undergrad organic chemistry or in medical school. I need to remember to reference your video when people ask me how MRIs work. Thank you.
Maybe do PET and CAT scans next? CZcams loves PET/CAT videos.
This is the future of science education videos.
Thanks Sabrine! Your channel is trully a unique gem of knowledge that is -accessible- to those who seek but not fully equiped yet nevetherless reaching ;)
I’ve had and MRI done and by the time I was done I had multiple superpowers, I can now manipulate matter and the effects of gravity. I’m imprisoned at a government facility and have been here for months, I’m only able to send this message out through my superpowers, gotta go! They’re onto me
Great video! Always wondered how mri machines worked, now I’m a little bit closer to understanding them. Thank you very much Sabine!!!
that was cool , love the diagram aid for the explination, thanks for doing these vids.
Fascinating as usual. I have to admit though, I like it better when you're calling out things that do not make sense to you. :) Thanks for all the fantastic videos.
My favorite channel. When people says "they say" I think of Sabine.
Great use of visualization, Dr. Hossenfelder! The rainbow-coloured spin diagram was especially helpful to visualize the two different aspects of the spin restoration.
Thanks so much for this video. It really demystified NMRI for me.
The thing that impresses me as much as Sabine's intelligence is her incredible wardrobe! Thanks again for your excellent videos, Sabine! And thanks for your honesty when discussing Physics and Physicists.
Infinite respect for all the scientists, doctors, engineers and other practitioners who understand, develop and implement these technologies.
I am a cancer patient who stands a pretty good chance of survival thanks to your hard work and dedication.
Thank you, Thank You, THANK YOU!!! YOU ARE MY HEROES!!!
They are no heroes with their many crimes against humanity.
Best channel I discovered recently!
I've had to learn how to read MRIs as a layperson for my clients who have been traumatically injured. Many doctors and radiologists over the years taught me tidbits on what to look for. But this video helped explain a lot about how the cells vibrate or "spin". This video explains a lot. Thank you.
Im just watching this for my masters lab course and it really helps, thanks! :)
Applied physics is very interesting. It's good you devoted a little time to it. Nice video.
Thank you Sabine. Medical Physics was my field upon graduating 40 years ago and I have returned to it in recent years. I do wish and hope that more young physicists will turn to this fascinating and useful field.
Thank you for the excellent selection of topics, your clear and lucid explanations, and, above all, promotion of scientific temper!
Great video Sabine! You explain everything so well! Great outfit as usual!
Very good explained. Two of my teachers of experimental physics tryed to explain me MRI without any succeed. I would like all of the german teachers being like Sabine.
The only woman I know of who really does know everything!
Oh, lots of things I don't know. And I'm glad that is the case because otherwise life would be extremely boring!
@@SabineHossenfelder one of the skills gained from a doctorate or high level research is knowing where to look for information and how to filter out the noise and extract the main concepts and conclusions.
Another important attribute to possess is the ability to ask the right questions. The life of Socrates was based on this
@@SabineHossenfelder The real problem, huge problem, for all people in the world, is when the experts do not know ... the true foundations of their own expertise.
And when these true foundations are discovered by somebody, even greater problem arises: the greatest experts, and/or the most notorious (publicly exposed) experts, do not want to know that, and do everything what they can to sabotage the efforts that these truths become known to public. Actually, they do not need to do much to sabotage that: it is sufficient that they just ignore that.
Sad behavior. Malicious behavior. The bahavior of ... narcopaths:
soulmateinhell.blogspot.com/2016/02/the-most-dangerous-kind-of-narcopath.html
qr.ae/pNn9xf "The pillars of society ...".
Unfortunately, there's nothing new about that:
cs.uwaterloo.ca/~shallit/Papers/stages.pdf
en.wikipedia.org/wiki/Planck%27s_principle
That what you do not know, and what you definitely should know, what you definitely have to know, and what you were definitely able to discovere on your own, is here:
independent.academia.edu/ZDimi%C4%87
Freely available for everybody, just like the air we breathe ...
"All truths are easy to understand once they are discovered; the point is to discover them." - Galileo Galilei
And, in order to discover them, one just needs to be ... not-NPD person, and not taught/guided by NPD person(s).
So you know lots of men who know everything?
She is a very learned person and bright, but she would be the first to tell you how little she actually knows
This was truly outstanding. Love your videos and look forward to each new one.👏
Congratulation for that episode. Overall, very well explained what MRI is, from a man who worked almost 40 years in the MRI Industry.
Awesome video! The derivation of differential equations by physicists (in general) is amazing.
Thank you for this very helpful explanation. As a Geophysicist, I use Proton Precession Magnetometer, PPM for short, and that is really helpful for discarding external total field perturbations because of the very tiny Earth magnetic field to be measure. Congratulations for adding sponsors to your videos 👏
Sabine, thanks for another very lucid explanation of a subject, this time it was magnetic resonance imaging. Keep up the great work. Best wishes. Uldis
Thanks!
@@SabineHossenfelder Sabine, your my current science hero and I just wish there were more honest ones like you who help budding scientists move beyond traditional mythological physic's theories. Your the best!
Nice, clear and concise explanation👍
Just to say, NMR machines are also used in in Organic Chemistry Research labs all the time. NMR is probably the most important technique available for deciphering the structure of newly synthesised molecules😃👍
Thank you so much for these many wonderful videos. I have watched them all and shown them to my friends. One small thing: NMR and MRI involve RF magnetic fields that are generated and detected in the near-field. There really are no electromagnetic waves involved.
Makes me wonder what you know about electromagnetism.
Hint search for an electromagnetic spectrum image.
it's a start.
Ah, you are right of course. Sorry for the somewhat sloppy use of terminology.
@@a.randomjack6661 At distances under a single wavelength (near field), the EM wave is not well formed yet.
Thanks for the understandable explanation.
Excellent as usual. I enjoy all of your content. Thank you.
I am reading your book and I can hear your voice while I am reading it. 🤭 The way you share information with us made me to get interest again in science. Thanks for doubting.
A friend once told me that it had to do with the particles' spin... I was very intrigued by that at the time but I couldn't really understand it by then. It's great to have you shed some light on this subject and get to learn more about it in such detail. At first I thought that the explanation was that everything had to be related to its quantum effects since all matter is made of atoms", which is just dumb and reductive. Now I can see it more clearly (hopefully) and I understand that it's just like a lab reading of the collapsed state of the electrons' spin, induced by the a very strong magnetic field... Thanks for the great explanation, that was spot on!
Thank you again Professor, I actually understood what MRI is. Thanks.
Short and wonderful!
That is Wonderful I always wondered how they work
I had one on my brain in September. Got another one on my neck soon.
I've got a copy of my head MRI on my laptop. It's fascinating to look at for so many reasons.
About 9 years back, I had undergond MRI scan of spine. But, even the technicians who did it could not explain how the images were generated. Many thanks for this instructive and informative viewo.
So interesting as always. Thank you.
@Sabine Hossenfelder, I really must thank you for this video! I had always assumed that my 2nd cousin (once removed) Felix Bloch won his Nobel Prize in Physics for his work at the Stanford Linear Accelerator! This is probably because all I knew about him was that he was working there when we moved to California in the early 60s and that he was a famous Physicist. SLAC was located a few miles from my High School (and my mother never failed to point it out when we passed, asking me "What happened to me, already, that I was getting a C- in Algebra when we had a Nobel Prize winner in the family?"). I'm really happy that I watched this video today and heard his name for the first time in over 40 years. I now know a lot more about him and how he contributed to so many areas of Physics, with results that have really impacted our lives (like MRI, semiconductors, quantum computing and so much more). Thanks!
Good short explanation. Now I'd like to see more detail on how the quarks line up to make the spins of the hadrons, and how the spin precession works with spin quantization.
Another very interesting video. I was recently trying to refresh my memory about calculus when I came across your differential equations video. Now I have a new favorite science channel AND a new favorite music channel. Thanks!
regaridng differential equations see. www.technologyreview.com/2020/10/30/1011435/ai-fourier-neural-network-cracks-navier-stokes-and-partial-differential-equations/?fbclid=IwAR3AK_LZJAQCk9T8oB6FoRLeILFvK2l4nmDDCU75iDt4j57HFLBb4s_bJqk
SABINE has become a LIVING BILBOARD!!! Congratulations, Sabine. You're making progress ...
I admire and fascinated by his brilliant knowledge, a lady who has vast knowledge of physics and chemistry.. Thank you very much for the scientific info.
Sabine, back in the early 70's one of my chemistry profs did a lot of NMR work. One time he forgot to take a wrench out of his back pocked before turning on the magnet. Good thing a student assistant was around to turn it off since his ass was stuck to the machine! Fun times.
MR works with the constant magnetic field. The reason to apply sinusoidal magnetic field is to detect the resonance Larmor frequency. Thanks a lot for preparing this video.
I hope this channel blows the eff up
Excellent explanation Dr. Hossenfelder, thank you..!!
And this is one of the reasons why i want to be a medical physicist. Thank you Sabine.
I resonate to your image Sabine.
When we played with NMR in college physics (in the early 1970's), the sample size was under 10cc. Fast-forward 40 years, and the sample size is me!
Loving these videos, they're just easy enough that lay people can understand and still make us push slightly harder to seek out more (only just though!), also nice clothes; keep that up you look fantastic!
I had one of these, and a PET scan, that scared me more because of the matter-antimatter annihilation. They told me my brain was completely normal and I felt a bit disappointed
lol Right. I hate it when doctors can't find out what's wrong with you. "But, what about these symptoms?" Eventually, they kinda shrug their shoulders.
In particle physics, we have a lot of decommissioned solenoids. These could be used for really open MRIs at high fields. The magnet from the Argonne 12ft Bubble chamber now sits in unused in a SLAC PEP interaction region since the B-factory was retired.
This is a good account of how magnetic resonance works. But that seems to be just a part of the workings of an MRI scanner, with detection and computational imaging challenges left unexplored.
This video had my head spin!
What a wondrous explanation of a very complex fenomen.
May I suposse one day you will explain the machine who detects positrons emitted by our bodies?
The time i spent on this video is Really worthy.
Yay!! this time i could understand almost everything (apart of those strings of weird characters).
The inventor of NMRI Edward Mills Purcell was the Senior Staff Physicist at Area 51 for decades! ..and headed the CIA's "Project Rainbow"!
I'd LOVE to see a video on that!
Thanks for the explanation. I been asking myself how it works for a while. (Just at awkward times with no access to a computer to look it up)
I've had a couple of MRIs done. I was surprised at how loud it was. It sounded like very large solid metal blocks crashing together. I wondered how the machine stayed together. I was told that there actually aren't any moving parts!! What???
The sound I was hearing was caused by the effect on my ears from the rapid change of the very powerful magnetic field. I'm not sure why my brain "heard" it but wow!! It was loud.
(later) Okay, I looked it up. The rapid change of magnetic field causes the gradient coils (used to generate the magnetic field) in the machine to vibrate.
There's also ESR. With NMR a frequency modulated field makes a sinc function map. Spinning a sample in a field can make an fm modulation depending on spin speed. If you can reduce electron orbital occupation of catalytic orbits then chemical catalysis rates can be controlled by fields.
Why couldn't you have been my teacher? You explain everything in such a way that makes it much more interesting. This from a guy that would find all this boring if anyone else was presenting it. And you sing to! Amazing! ❤️
very cool i always wondered how mri machines work -- its fascinating and a lot of fun to think about -- and yes you explained it very clearly for us non-physicists i understood it -- this was perfect for a quick break from work today -- danke dr. hossenfelder!
And that's how modern Dubstep was born.
ha ;)
Put a wonk on it
Isidor Rabi discovered NMR in the 30s. Also most nuclei do not align or anti align with the applied field, the polarization is only about 1 ppm
I love your explanation
Very nice explanation
Interesting. Thanks
A very clear and complete 👌💯explanation of the physics of NMRI.
♫ You spin me right round, baby right round, like a nucleus, baby right round, round, round... ♫
Could you do more videos about technology we use in physics, such as calculus of variations, gradient/curl/divergence, tensors, QFT ...?
Better explanation than my Neurologist gives me. I have to get one periodically for a syrinx at the C2 level, and yes, I often wonder if it will cause damage at the cellular level, like mutate me or something.
Sabine, I have seen your arguments against building yet another collider at CERN and was impressed.
I recently saw, on a different channel, suggestions that building fusion reactors to generate electricity is a similar waste of public funds. Would be interested to see your take on this, if you can make the time to treat it with your usual thoroughness.
Thanks.
I am a MRI consultant.. the physics is glorious and the math even moreso.... It doesn't spin, it precesses just like the earth.
I never really understood before how NMR could be used to get images. Thanks!
I read about the invention of MRI's last year, quite interesting. And how the main force behind its creation really got no credit for all his work and progress. I teach this a little in one of my classes, glad I got the stuff I need to be right on, well, right.
But you missed one of the most important things under "8.11 Health risks" . Those awful scary loud noises! What are they and what causes them, I think we should be told ;) ... Thanks for another great video, always make breakfast so much more stimulating.