Aa
Is it always L'Hermitte's?
I'm curoius about this new symptom I've developed. When I tilt my head up, I get a buzzing in my upper back, right below the neck. Now I know that typically a lesion in the neck will cause this problem, but is it possible that the lesions in my upper back are to blame?
Hi there,
and thanks for sharing,
Jen I am glad that the lead up to Christmas has not fatigued you, as it sure has me!! But we are coming into our summer and I seem to suffer from Uthoffs , my symptoms are always worse when I get too hot.
Bob,
I find all that interesting, although it might go over my head a little, or maybe a lot! I researched how the MRI machine worked as I have had so many of them on T3 machines that I was curious about what they could and couldn't do, my son in law is a radiologist too, so I have quizzed his brains as well and my dear friend works in the oncology unit (she does have a fancy name) and a UNI degree but she was the one who told me about how it spins etc., sounds like a washing machine.
Jen I was never allowed to wear any jewellery when I have had mine done. We don't have a T7 machine here yet, but I would love to try it to see if it really did show these elusive lesions that I am meant to have. All our machines are T3 though, we don't have any old ones at all!
Interesting tho as I have always felt a bit hot when I have had my scan done, but I was assuming it was just me feeling hot..lol.
Merry Christmas to you both, I hope you have a very Merry Christmas and a Happy New year.
and thanks for sharing,
Jen I am glad that the lead up to Christmas has not fatigued you, as it sure has me!! But we are coming into our summer and I seem to suffer from Uthoffs , my symptoms are always worse when I get too hot.
Bob,
I find all that interesting, although it might go over my head a little, or maybe a lot! I researched how the MRI machine worked as I have had so many of them on T3 machines that I was curious about what they could and couldn't do, my son in law is a radiologist too, so I have quizzed his brains as well and my dear friend works in the oncology unit (she does have a fancy name) and a UNI degree but she was the one who told me about how it spins etc., sounds like a washing machine.
Jen I was never allowed to wear any jewellery when I have had mine done. We don't have a T7 machine here yet, but I would love to try it to see if it really did show these elusive lesions that I am meant to have. All our machines are T3 though, we don't have any old ones at all!
Interesting tho as I have always felt a bit hot when I have had my scan done, but I was assuming it was just me feeling hot..lol.
Merry Christmas to you both, I hope you have a very Merry Christmas and a Happy New year.
I had a 3T for the first time in September. Got a little hot for that first scan, but the rest were okay. The weirdest thing was that my wedding ring was 'clicking' for that first scan, too.
Still, doesn't hold a candle to the heat felt during my CT scan!
Still, doesn't hold a candle to the heat felt during my CT scan!
Geek warning - the following talks about why you feel like your getting hot in an MRI.
Just remember 7 Tesla may give better images, but it is also a kind of oven for small skinny people. The Hydrogen 1 Proton has a Larmor frequency of 42.58 MHz per Tesla, so a 1.5T MRI has a Larmor Frequency of 63.87 MHz, a 3T is 127.74 MHz and a 7T is 298.06 MHZ.
The issue here is that the SAR (Maximum Specific Absorption Rate) for MRI energy is capped at 4 watts per kilogram total body weight by the FDA. When they punch in your weight, the machine changes its "duty cycle" (the time between spinning up your molecules - the thumping) so you don't exceed the SAR. So the 7T is spinning up the water molecules even faster (4.67 times) and listening at almost 300MHz compared to the 64 MHz on 1.5T. So much shorter duty cycles or more heating.
The smaller you are, the longer the scans take. Someone has already contacted me on this forum about feeling heat in their neck during a scan. I checked the biomedical engineering database at ECRI (Emergency Care Research Institute) and this is already a well reported issue. Oh, by the way. While the 1.5T is OK for some surgical implants, the 3T is already having issues with stents, monitoring leads, some heart valves, etc. This will be a greater issue with the 7Ts. At 70,000 gauss, you can actually pick up most stainless steel alloys.
The magnetic field of the MRI vibrates the molecules a similar way the magnetron in the Microwave oven does, The magnetron uses RF to make the molecules of water in a steak vibrate at 2450MHz so things heat up much faster than in an MRI. When you set the Microwave power to 10 that is 100% duty cycle. When you set it to 2 that is 20% duty cycle.
Might be more than you wanted to know.
Bob
Just remember 7 Tesla may give better images, but it is also a kind of oven for small skinny people. The Hydrogen 1 Proton has a Larmor frequency of 42.58 MHz per Tesla, so a 1.5T MRI has a Larmor Frequency of 63.87 MHz, a 3T is 127.74 MHz and a 7T is 298.06 MHZ.
The issue here is that the SAR (Maximum Specific Absorption Rate) for MRI energy is capped at 4 watts per kilogram total body weight by the FDA. When they punch in your weight, the machine changes its "duty cycle" (the time between spinning up your molecules - the thumping) so you don't exceed the SAR. So the 7T is spinning up the water molecules even faster (4.67 times) and listening at almost 300MHz compared to the 64 MHz on 1.5T. So much shorter duty cycles or more heating.
The smaller you are, the longer the scans take. Someone has already contacted me on this forum about feeling heat in their neck during a scan. I checked the biomedical engineering database at ECRI (Emergency Care Research Institute) and this is already a well reported issue. Oh, by the way. While the 1.5T is OK for some surgical implants, the 3T is already having issues with stents, monitoring leads, some heart valves, etc. This will be a greater issue with the 7Ts. At 70,000 gauss, you can actually pick up most stainless steel alloys.
The magnetic field of the MRI vibrates the molecules a similar way the magnetron in the Microwave oven does, The magnetron uses RF to make the molecules of water in a steak vibrate at 2450MHz so things heat up much faster than in an MRI. When you set the Microwave power to 10 that is 100% duty cycle. When you set it to 2 that is 20% duty cycle.
Might be more than you wanted to know.
Bob
Thanks, sweetie! I agree 100% - the neuro doesn't have to see the lesion on the MRI to know something's there. Other than that, I'm doing fine - feeling healthy and not too fatigued.
Hi Jen,
I would tell your neuro.
And even if your MRI is "normal" it does not mean you don't have a lesion there.
Words of wisdom by my neuro.
T7 MRI are showing lesions that T3 are not, so therefore it is still quite reasonable that T3 machines and even T7 are not showing all the lesions that are really there. MRI is a tool to help diagnose and eliminate other diseases but should not take the place of a good patient history and examination and can be used in conjunction with these things. It was explained to me in this way, we can look at Mars with a telescope and not see everything but it does not mean that the things are not there, we just don't have the technology yet to image our spinal cords and see everything, I know it's there because your symptoms and your history and your examination are showing and telling me that you have a lesion in your cervical. I would much rather him say that than fob me off and tell me I am insane when I am clearly not!! (well under debate) :-)
I have a doctor who trusts his own ability enough to diagnose me after undergoing all the rule outs and lots of testing on a clear MRI. He also reckons this is why I get my migraines too, said that migraines can go hand in hand with a cervical lesion.
Good luck with your visit, keep us posted, sorry to hear you are getting worse right on Christmas time.
Cheers,
Udkas.
I would tell your neuro.
And even if your MRI is "normal" it does not mean you don't have a lesion there.
Words of wisdom by my neuro.
T7 MRI are showing lesions that T3 are not, so therefore it is still quite reasonable that T3 machines and even T7 are not showing all the lesions that are really there. MRI is a tool to help diagnose and eliminate other diseases but should not take the place of a good patient history and examination and can be used in conjunction with these things. It was explained to me in this way, we can look at Mars with a telescope and not see everything but it does not mean that the things are not there, we just don't have the technology yet to image our spinal cords and see everything, I know it's there because your symptoms and your history and your examination are showing and telling me that you have a lesion in your cervical. I would much rather him say that than fob me off and tell me I am insane when I am clearly not!! (well under debate) :-)
I have a doctor who trusts his own ability enough to diagnose me after undergoing all the rule outs and lots of testing on a clear MRI. He also reckons this is why I get my migraines too, said that migraines can go hand in hand with a cervical lesion.
Good luck with your visit, keep us posted, sorry to hear you are getting worse right on Christmas time.
Cheers,
Udkas.
Thanks, Udkas! Hmm.... well, I do have mild degenerative neck whatsis, so I guess that could be a cause of it. But I don't think the 'old lady neck' would account for that reaction. Guess I've got something else for the neuro!
I have Lhermittes and the way my neuro explained it to me I think it is only from a lesion in your cervical (neck), apparently you can get Lhermittes without having MS it can occur from injury etc. but it is usually to the cervical.
In my case he reckons I have a lesion but you can't seem to see it, but I sure do get the lhermittes when I flex my neck..., I get like an electrical current zapping thru my spine, almost like touching an electric fence it tingles down thru my neck and downwards to my big toe..lol it kind of shoots quickly.
Flexing down only, creates this with me.
As you know Jen I am diagnosed with a normal MRI m(TM) but my Neuro is I think confident enough to diagnose me on my symptoms and his findings. He said Lhermetts means cervical lesion.
CHeers,
Udkas
In my case he reckons I have a lesion but you can't seem to see it, but I sure do get the lhermittes when I flex my neck..., I get like an electrical current zapping thru my spine, almost like touching an electric fence it tingles down thru my neck and downwards to my big toe..lol it kind of shoots quickly.
Flexing down only, creates this with me.
As you know Jen I am diagnosed with a normal MRI m(TM) but my Neuro is I think confident enough to diagnose me on my symptoms and his findings. He said Lhermetts means cervical lesion.
CHeers,
Udkas
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Good question Jen, sorry cant answer the question though, funny i cant put my chin on my neck at the moment, the right side of my neck goes into spasms, I didn't know that lol
I dont think i've ever had buzzing even when I could do it, the electric shock feeling other people mention is not something i've experienced either, so can't say i relate. The buzz i know, i can't say i've ever felt it when i tilt my head down, i do feel something odd and my fingers go numb pretty quickly but my fingers go numb just lifting my arm so its not the same thing that your talking about, sorry.
Wooops tilt up and i fall backwards, forgot that would happen, dont they say curiosity killed the cat lol
I'm sure someone has the answer though not much is happening on the forum at the moment so it may take awhile.
Cheers.........JJ
I dont think i've ever had buzzing even when I could do it, the electric shock feeling other people mention is not something i've experienced either, so can't say i relate. The buzz i know, i can't say i've ever felt it when i tilt my head down, i do feel something odd and my fingers go numb pretty quickly but my fingers go numb just lifting my arm so its not the same thing that your talking about, sorry.
Wooops tilt up and i fall backwards, forgot that would happen, dont they say curiosity killed the cat lol
I'm sure someone has the answer though not much is happening on the forum at the moment so it may take awhile.
Cheers.........JJ
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