I LOVE YOU! seriously, I have been working in MRI for a while and no one, no one has explained FE and PE the way you have. What an amazing talent. Thank you for sharing the fruit of it with us.
I can’t thank you enough for these videos. Each time I start on a new video I think "this is where I will get lost", but somehow your explanations never fail to make me understand! I wouldn’t have made it through MRI exam preparations without these videos. Thank you so much, you are great at teaching!😊
Wow thank you this is the most amazing series! I’m an MRI tech and I’m still learning and trying to understand this on a deeper level for my work! This video series has helped me more than any other lecture or test or book I have read. You put things into perfect detail! Simple and understandable but so informative! You are a great teacher and have such a gift! Thank you for sharing you amazing knowledge on MRI with us all! I know it has helped me tremendously already!
Wow! This had made my day! I'm so glad the videos have been helpful. Thank you for taking the time to write such a lovely comment. Really appreciate it 😊
Thank God I found you! I have been struggling to understand some points that didn't make sense for years and now everything is much more clear to me! Thank you very much!!!!
Thank you so much for the great content and for finally making these topics comprehensible for everyone. Greetings from a radiology resident from Germany
This lecture series is just great work! I am a researcher, currently on a quest to fully understand the Echo planar spectroscopic imaging (EPSI) sequence we used in one of our projects. I use this series as a refresher for the basics and really enjoy watching them.
I have given you a subscription so that I can show my gratitude and that you really go to a lot of effort to explain this in detail. Many greetings from Germany🗿
I love your tutoring. Trying to take my board exam soon. YOu mentioned that take some quizzes to practice, but I have not seen the link. Where can I see them to pratice? Thank you so much and so appreciate your kind effort.
Hej Michael, thank you for a great video! I got confused with one artifact which occurs in the frequency encoding direction: Zipper artefact. Why it is located in the row not a column. Creating one straight line in the row. It should be horizontal if it feels up column (x axis direction?)
Thank you so much for these videos! Slowly getting the hang of it!. I do have a question though When talking about transforming the acquisition data from a “time data” set to a “frequency data” set, made up different frequencies along the x axis (slower to faster/ left to right)… why does the newly generated data set show that on both ends, the signal is very dark or black? Although one end represents slow frequencies and the other represents those spinning at a faster pace? It would seem they should be reflected as opposite or one and being dark and the other bright….
If we're setting the frequency encoding gradient, why do we need to work out the frequencies? Can't we work that out as we know the precessional frequency is based on the magnetic strength along the x axis ?
Hello! I found the tutorial to be great, but I am a little confused. Isn't the "inverse Fourier transform" used to convert signals from the frequency domain to the time domain? If that's the case, then shouldn't the transformation from time to frequency be called the "Fourier transform" instead of the "inverse Fourier transform"?
At 19:25 you said it's an inverse fourier transformation but what you are explaining is you are converting time based data to frequency based data. Isn't it actually a normal fourier transformation? The caption also says it's a normal fourier transformation.
Hi. I cant understand how all the pulses afects the protons. I understand the Bo and slice selection gradient (both in the same plane) but I cant understand when we apply the frecuency encoding gradient (z plane or another plane) what happens with my transverse net magnetization vector ( if with the RF pulse te net magnerization vector start to diminish and lose the coherence but de 180° re phase and the SSG [positive and negative]). All secuentialy and the what happen with the decay (wich determine the echo and the signa?l)
Does each digital cell in the generated frequency encoding row represent the aggregate signal from that x-axis point over time of does it represent what that axis contributes to the overall NMV at a given point along wave?
When gradients are applied before rf pulses or at the same time.. If at the same time the how can we match the precisional frequency with rf pulse as body is Expercing same magnetic feield ..
when the FEG is turned on and there is a difference of frequency along the x-axis, this is all happening simultaneously with the protons all rephasing/dephasing from the 180 RF pulse? It is easy to visualize it separately but difficult to visualize them happening simultaneously. I'm not sure if my question makes sense but when the FEG is turned on, it seems we do not take into account the protons that are being influenced by the 180 degree RF pulse.
Yes, you’re right. This is extremely difficult to visualise the processes happening simultaneously. The reaccumulation of transverse signal is occurring after the 180 degree RF pulse (generation of a spin echo). When the FEG is applied, the frequency difference along the x axis causes phase incoherence (and loss of transverse signal). This is why we generate a gradient echo at readout - hopefully the gradient echo talk will help with this. The processes are happening simultaneously 🤯 It’s a miracle we get any usable signal..
Thank you for all your amazing work and making this available! Its been very helpful in trying to understand this complicated topic for my registry exam! Do you have the question bank availble for MRI yet? I would love to do that in addition to your videos to make sure i am understanding the material properly 😊
Thanks a lot for your explanation. I think your videos are great. However I think there is a gap in your explanation: how you harmonise the "Frequency encoding Concept" , that you explain it as a modulation in frequency being them disentangled via the Fourier Transform, with the fact that the whole K-space is a space of phases. Or in other words your are sampling a signal with a high bandwidth in order to capture all the potential frequencies in the rotating frame of reference, however, the "echo" in the K=space is represented by a really small amount of samples. In my opinion, "Frequency encoding" is an unfortunate term because the k-space only encodes "spatial frequencies" present in the object/tissue. An the spatial frequencies present in the object are defined by really small bandwidth (128, 256, 512, 1024..., corresponding to the conventional matrix size). The difficulty to fully understand MRI reconstruction via K-space encodings (phase and frequency) requires to connect temporal frequencies, present in the signal, and spatial frequencies, present in the object (I saw you nice tutorial about K-space as well I could make the same comment there). The k-space encodes 2-D or 3-D "spatial frequencies" via "Phase Encoding" and "Frequency encoding". Actually, the "frequency encoding" process makes more efficient the filling the k-space than the phase encoding (phase encoding only fix one particular Ky, but frequency encoding capture all the "Kx's" of a single Ky) but, at the end of the day all is about Kx,Ky pairs representing spatial frequencies from the object defined by the contrast induced but the amount of protons and the timing of the pulse sequence. In summary, I think is easier to understand phase and frequency encoding and the k-pace from the angle of spatial frequencies present or not in the object. Anyway, thanks a lot for you really nice explanations.
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
I LOVE YOU! seriously, I have been working in MRI for a while and no one, no one has explained FE and PE the way you have. What an amazing talent. Thank you for sharing the fruit of it with us.
Thank you so much. You’re too kind 🙂
Sus
I can’t thank you enough for these videos. Each time I start on a new video I think "this is where I will get lost", but somehow your explanations never fail to make me understand! I wouldn’t have made it through MRI exam preparations without these videos. Thank you so much, you are great at teaching!😊
Wow thank you this is the most amazing series! I’m an MRI tech and I’m still learning and trying to understand this on a deeper level for my work! This video series has helped me more than any other lecture or test or book I have read. You put things into perfect detail! Simple and understandable but so informative! You are a great teacher and have such a gift! Thank you for sharing you amazing knowledge on MRI with us all! I know it has helped me tremendously already!
Wow! This had made my day! I'm so glad the videos have been helpful. Thank you for taking the time to write such a lovely comment. Really appreciate it 😊
Thank God I found you! I have been struggling to understand some points that didn't make sense for years and now everything is much more clear to me! Thank you very much!!!!
I'm so glad! Thank you for a lovely comment 🙌
thank you very much dr, this is the best and clearest mri series i've ever watched
That's so kind to say! Glad you're enjoying the series 😀
Thank you so much for the great content and for finally making these topics comprehensible for everyone. Greetings from a radiology resident from Germany
Thank you! I appreciate it! Greeting from South Africa
You explain so well that you made me want to hear "Fourrier" because I understood why it was needed. This is truly impressive
This lecture series is just great work! I am a researcher, currently on a quest to fully understand the Echo planar spectroscopic imaging (EPSI) sequence we used in one of our projects. I use this series as a refresher for the basics and really enjoy watching them.
You are the best man. A life saver. Keep up the great work.
I am radiology resident from Pakistan.
Thank you. Appreciate it. Greeting from South Africa 🇿🇦
I have given you a subscription so that I can show my gratitude and that you really go to a lot of effort to explain this in detail. Many greetings from Germany🗿
Really waiting for CT videos to be released 😊
The effort and the quality put in this masterpiece is mind blowing😲
I can't explain how much I love you !! Feels great to finally understand this T_T
I share all your videos with my classmates Thank you so very much ❤
These videos are really well done! thank you for providing such quality content for free :)
Thank you so much for your Videos. I think by far you create the best radiology-related content.
Wow, thank you. That's very kind of you!
This stuff is awesome! You have such a talent for explaining things
I love your tutoring. Trying to take my board exam soon. YOu mentioned that take some quizzes to practice, but I have not seen the link. Where can I see them to pratice? Thank you so much and so appreciate your kind effort.
This section was a bit difficult ... watched the video 8 times to understand it properly 😅...
Thanks Michael 👏
Thank you so much. It's very easy to understand the topic. You are amazing 😊
Thanks Dr, love your videos and admire your knowledge and great explanation.
Excellent lecture! 😊
Love you brother
Hej Michael, thank you for a great video! I got confused with one artifact which occurs in the frequency encoding direction: Zipper artefact. Why it is located in the row not a column. Creating one straight line in the row. It should be horizontal if it feels up column (x axis direction?)
Thank you so much for these videos! Slowly getting the hang of it!. I do have a question though
When talking about transforming the acquisition data from a “time data” set to a “frequency data” set, made up different frequencies along the x axis (slower to faster/ left to right)… why does the newly generated data set show that on both ends, the signal is very dark or black? Although one end represents slow frequencies and the other represents those spinning at a faster pace? It would seem they should be reflected as opposite or one and being dark and the other bright….
you are just simply amazing... ❤❤
Thanks
Thank you 🙏🏻 appreciate your support!
REALY AMAZING, Can you please help us to explaining the other different sequences like GRADIENT, SWS, MRA, etc
Thank you! Starting pulse sequences next week 🙂
vielen dank @@radiologytutorials
If we're setting the frequency encoding gradient, why do we need to work out the frequencies? Can't we work that out as we know the precessional frequency is based on the magnetic strength along the x axis ?
Hello! I found the tutorial to be great, but I am a little confused. Isn't the "inverse Fourier transform" used to convert signals from the frequency domain to the time domain? If that's the case, then shouldn't the transformation from time to frequency be called the "Fourier transform" instead of the "inverse Fourier transform"?
I agree with you. This is a Discrete Fourier Transform and not an inverse FT
Save my final! thanks so much
Amazing lecture
Thank you 🤗
Thank you so much for making my life easier what would i do with out this series
At 19:25 you said it's an inverse fourier transformation but what you are explaining is you are converting time based data to frequency based data. Isn't it actually a normal fourier transformation? The caption also says it's a normal fourier transformation.
The inverse Fourier Transform is used in image processing, where it is used to convert images from the frequency domain to the spatial domain
@@tysonbrown543 inverse fourier transform and fourier transform are essentially the same operation
Hi. I cant understand how all the pulses afects the protons. I understand the Bo and slice selection gradient (both in the same plane) but I cant understand when we apply the frecuency encoding gradient (z plane or another plane) what happens with my transverse net magnetization vector ( if with the RF pulse te net magnerization vector start to diminish and lose the coherence but de 180° re phase and the SSG [positive and negative]). All secuentialy and the what happen with the decay (wich determine the echo and the signa?l)
Does each digital cell in the generated frequency encoding row represent the aggregate signal from that x-axis point over time of does it represent what that axis contributes to the overall NMV at a given point along wave?
Wowww.... thankyou so much sir!!!!
When gradients are applied before rf pulses or at the same time.. If at the same time the how can we match the precisional frequency with rf pulse as body is Expercing same magnetic feield ..
Thank You! 👏👏👏👏
when the FEG is turned on and there is a difference of frequency along the x-axis, this is all happening simultaneously with the protons all rephasing/dephasing from the 180 RF pulse? It is easy to visualize it separately but difficult to visualize them happening simultaneously.
I'm not sure if my question makes sense but when the FEG is turned on, it seems we do not take into account the protons that are being influenced by the 180 degree RF pulse.
Yes, you’re right. This is extremely difficult to visualise the processes happening simultaneously. The reaccumulation of transverse signal is occurring after the 180 degree RF pulse (generation of a spin echo). When the FEG is applied, the frequency difference along the x axis causes phase incoherence (and loss of transverse signal). This is why we generate a gradient echo at readout - hopefully the gradient echo talk will help with this. The processes are happening simultaneously 🤯 It’s a miracle we get any usable signal..
Amazing❤
Thank you! Next video drops tomorrow 🙂
Thank you for all your amazing work and making this available! Its been very helpful in trying to understand this complicated topic for my registry exam! Do you have the question bank availble for MRI yet? I would love to do that in addition to your videos to make sure i am understanding the material properly 😊
So glad I could be helpful! Busy working on the question bank right now - hoping it'll be available soon 🤞
The frequency encoding direction is not always on the x-axis it can change from x or y depending on your scanner correct?
Correct. You can chose the frequency and phase encoding directions. Just use the label x axis by convention 👍🏼
Thanks a lot for your explanation. I think your videos are great. However I think there is a gap in your explanation: how you harmonise the "Frequency encoding Concept" , that you explain it as a modulation in frequency being them disentangled via the Fourier Transform, with the fact that the whole K-space is a space of phases. Or in other words your are sampling a signal with a high bandwidth in order to capture all the potential frequencies in the rotating frame of reference, however, the "echo" in the K=space is represented by a really small amount of samples. In my opinion, "Frequency encoding" is an unfortunate term because the k-space only encodes "spatial frequencies" present in the object/tissue. An the spatial frequencies present in the object are defined by really small bandwidth (128, 256, 512, 1024..., corresponding to the conventional matrix size). The difficulty to fully understand MRI reconstruction via K-space encodings (phase and frequency) requires to connect temporal frequencies, present in the signal, and spatial frequencies, present in the object (I saw you nice tutorial about K-space as well I could make the same comment there). The k-space encodes 2-D or 3-D "spatial frequencies" via "Phase Encoding" and "Frequency encoding". Actually, the "frequency encoding" process makes more efficient the filling the k-space than the phase encoding (phase encoding only fix one particular Ky, but frequency encoding capture all the "Kx's" of a single Ky) but, at the end of the day all is about Kx,Ky pairs representing spatial frequencies from the object defined by the contrast induced but the amount of protons and the timing of the pulse sequence. In summary, I think is easier to understand phase and frequency encoding and the k-pace from the angle of spatial frequencies present or not in the object. Anyway, thanks a lot for you really nice explanations.
Thank you doctor 😊
Most welcome! ☺️
Please make videos on ct physics, i request
Thank you Sir.
You are most welcome Dr Zubia
my brain exploded
great dr
Thank you 🙏🏻
Thankyou sir🙏🙏
It’s my pleasure Sohail 🙏🏻
❤️🔥❤️🔥
💝💝
🥰🥰
Thanks Dr, love your videos and admire your knowledge and great explanation.
Thanks Dr, love your videos and admire your knowledge and great explanation.
Thanks Dr, love your videos and admire your knowledge and great explanation.
Thanks Dr, love your videos and admire your knowledge and great explanation.
Thanks Dr, love your videos and admire your knowledge and great explanation.