Introducing MRI: Transverse Magnetization Relaxation (10 of 56)

www.einstein.yu.edu - The tenth chapter of Dr. Michael Lipton's MRI course covers Transverse Magnetization Relaxation. Dr. Lipton is associate professor radiology at Albert Einstein College of Medicine and associate director of its Gruss Magnetic Resonance Research Center.

[@jang3035]

Dr Lipton is fantastic. My prof has a lot to learn. He can't explain anything in MRI. The whole class is lost. I will recommend this video. Thanks. Dr. Lipton.

[@amirmikhchi4724]

Looking at several sources, it seems T2 is the time it takes to *drop down* to 37% (which means losing 63%)of what your initial magnetization was. The video says we *lose* 37% (which would imply we have 63% of our initial leftover).
Source: en.wikipedia.org/wiki/Spin%E2%80%93spin_relaxation
Also just for completeness, an earlier video in this series states the net magnetization vector (NMV) of spins due to external magnetic field (B0) is in the anti-parallel direction. Every other source I've looked at has said the NMV is actually in the parallel direction.

[@EinsteinCollegeofMed]

+Amir Mikhchi Dr. Lipton writes: "Thanks for your comment. You are correct that the time t2 is the time during which 63% of net mt dissipates. That is, after one time period = T2, 37% of the mt that was present initially remains. This is in fact how it is stated in my book (www.amazon.com/totally-accessible-mri-principles-applications/dp/0387488952). I am not sure what caused me to misspeak in this segment (cosmic ray, stage fright, full moon...), but in any case apologize for the confusion. I am glad to see you catch me!"

[@graedy2]

Would be nice if you could add a disclaimer to the video correcting this mistake (youtube makes it very easy to edit those in). Your videos are by far the best explanations for NMR I have seen so far but this T2 explanation error confused me a lot and will confuse everyone I reccomend those videos to. Having given lectures myself I fully understand how one sometimes just does very confusing stuff when explaining the same things for the thousands time. There is absolutelly no shame in that.

[@RudradeepMukherjee]

@@graedy2 In my humble opinion, I think T2, T1 and so on are arbitrary notations. I may call them beta1 or beta2, if I wish. Strictly speaking, Dr. Lipton is not incorrect for labeling 37% drop point as T2 if he consistently uses it in the context of his discussion.

[@ihsahnakerfeldt9280]

@Rudradeep Mukherjee Doesn't matter if he consistently uses it this way. It's still wrong. T2 is an internationally agreed upon definition and a constant that is measured for different substances and if students got out of this lecture thinking it's the time required for signal intensity to drop BY 37% as opposed to TO 37%, they'd be associating these measured constants with the wrong concept.

[@najmeh2430]

I really learned a lot from your videos thank you🙏🏻

[@user-uk1sp2tq6k]

It is a very good explanation, however it is not 100% correct.
Dr. Lipton saying that T2 is an amount of time to get to a point where transverse magnetization has lost 37% of its original value. It cannot be mathematically.
If T1 is a time to get to a point where longitudinal magnetization has returned to 63% of its original value, so that means that exactly at this point transverse magnetization has lost 63% (not 37%) of its original value and accordingly we have 37% left of that transverse original value. Whatever longitudinal returning, transverse losing and vise versa.
So, T2 is an amount of time to get to a point where transverse magnetization decay to 37% of its original value (not lost 37% of its original value).
On the graph "37%" must be on lower portion of Mt.
Thank you.
Here are correct graphs of T1 and T2
www.imaios.com/en/e-Courses/e-MRI/MRI-signal-contrast/Spin-echo-TR-TE

[@jerejh3]

thanks, this made sense

[@landrewmackinnon4888]

I was bothered by that portion as well. Glad I found this comment.

[@abdovitamins6331]

He should have saying( lost 63%) of transverse magnitization

[@whytemaamba]

wait a second, wait a second.... I don't get it

[@sathi2293]

Incorrect facts intermittently