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Demylenating versus ischemic lesions?
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Demylenating versus ischemic lesions?

Does anyone know what criteria radiologists make a determination regarding the nature of lesions in the brain or spine as being caused by demylination or ischemia?  Ann mentioned in her post that her lesions were reported as possible demylination, yet I see others with similar findings stating ischemia.  How do they know the difference?  Does it have to do with where they find the lesions in the brain, for example?  Just curious - Inquiring minds...Thanks.

Julie
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572651_tn?1333939396


Julie,
I found this journal article that sort of helps ... LOL
If I am reading it correctly, the way the MRI magnet signals bounce off and are absorbed by the lesions helps them to determine what type they are.  The ones caused by lack of blood flow (ischemic)  show magnetization at a much higher rate than lesions caused by demyelination.  How does that sound for an answer?  If I have read this wrong, someone out there please correct me.

My best,
Laura

http://www.ajnr.org/cgi/content/abstract/17/6/1051

Measure of magnetization transfer in multiple sclerosis demyelinating plaques, white matter ischemic lesions, and edema


PURPOSE: To define the percentage of magnetization transfer of multiple sclerosis (MS) plaques, ischemic white matter lesions, and vasogenic edema to determine whether this measurement can help differentiate these entities. METHODS: Findings were compared in 25 patients with proved MS, 20 patients with white matter ischemic lesions, and 72 patients with white matter edema (caused by tumors, infections, or acute/subacute infarctions) in the periventricular system, centrum semiovale, and subcortical white matter. Magnetization transfer was performed using an on-resonance binomial pulse. The percentage of magnetization transfer of the normal white matter was also calculated. RESULTS: Magnetization transfer was significantly higher in white matter ischemic lesions (range, 31% to 38%; mean, 34% +/- 0.6%) than in demyelinating plaques of MS (range, 19% to 28%; mean, 22.5% +/- 1%) and in edema (range, 29% to 37%; mean, 30.2% +/- 0.4%). No statistical difference in percentage of magnetization transfer was found among lesions in the periventricular system (34% +/- 0.6%), centrum semiovale (35% +/- 0.5%), or subcortical white matter (33% +/- 0.6%), or in vasogenic edema associated with tumors, infections, or infarction. CONCLUSION: Differences in magnetization transfer suggest less change of demyelination in white matter ischemic lesions than in MS plaques and are significantly different in this respect from similar MS plaques. Magnetization transfer of edema was less than that of normal white matter or fell between ischemic abnormalities and MS plaques. Percentages of magnetization transfer below the mid-20% range is highly suggestive of demyelination. Vasogenic edema, our surrogate for increased water content of white matter, caused a decrease in the percentage of magnetization transfer.


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Your quick research skills never cease to amaze me.  

So, what is your take on the below excerpt from the article you cited?

"No statistical difference in percentage of magnetization transfer was found among lesions in the periventricular system (34% +/- 0.6%), centrum semiovale (35% +/- 0.5%), or subcortical white matter (33% +/- 0.6%)"

Does this sound like it makes a difference in the location where the lesion is found in the brain?  

Julie
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The differences are in things like location, shape of lesion, and something called "diffusion."  As I understand it, ischemic lesions are less well demarcated (less well defined borders) because they are from the closing off of arteries and the damage is less, the farther you are away from where the blockage was.  Ischemic lesions are always right around the vascular areas.

There is a site called "radiologyassistant" that describes this type of thing.  

But, there is overlap, especially when the lesions are not perfectly characteristic of either type of lesion and there is some overlap in location.  Ischemic lesions are typically subcortical, whereas MS lesions are more "juxtacortical" when they are in that area.  The problem is that many radiologists do not distinguish between "just below" the cortical junction with the whitel matter and lying "across" the jucntion between the cortex (gray matter) and the white matter.

These are all subtle differences and the interpretation depends on the skill and experience of the person reading them.

Try the Radiology Assistant site.

Quix
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Is it me?  Or is there a lot of discretion, therefore, left to the radiologist...For example, one radiologist may suggest ischemic lesions and another may suggest demyelation?  Interesting, huh?  Ive always had a problem with the fact that there is so much discretion in the rheumatological field as well, and what different docs feel different test results indicate.
My last MRI (done 3 years ago) said multiple lesions that could represent ischemic lesions.  My neuro at the time still felt it was a chronic neurological virus causing the lesions, and I accepted that at the time.  I actually just made an appt with my first neuro in 3 years, and my appt is at the end of October.  She put me on a cancellation list, though.  You know, my rheumie is OK, but anything  that doesnt DIRECTLY affect the joints he brushes off...This includes the really bad edema I had when I was in his office once, and last time I saw him and told him how sick Ive been - pain, fatigue, swelling, bad neuro sxs, etc...he kind of insinuated it was the lupus.  Then he prescribed me Imuran, which is a DMARD for lupus, but didnt talk at all to me about the side efffects.  I had to find out on my own that, being an oral chemo (though it is too weak to use in cancer) it can cause hair loss, nasuea, vomiting...all that kind of stuff.  You'd think he would have mentioned that, yes?  There is a great website (I dont know actual address) that has patients giving their experience with medications.  If you google "side effects of *enter medication*, you will see a website called something like patient review, or something similar...does that even make sense?  Im sorry, my brain fog is ridiculous recently...I can barely hold a conversation.  I find myself kind of just staring at the person talking..a continual daydream....I HATE that...usually my vision is messed up at the same time the brain fog is really bad, like they go hand in hand.  
OK - kind of went off here, sorry....thanks for listening
Love Lauri
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572651_tn?1333939396
one other point - I hand carried my spine MRI's and radiologist report to my neuro appt.  He handed the report back to me and I asked him if he didn't want them.  He was emphatic about the no - he did not want to read the report.  I mentioned this to someone here - I don't remember who - and they said that was a good thing.  A neuro should not be influenced by another's opinion about the films.  I don't know if this really fits into this thread, but here it is!

Laura
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okay, this might be the right place to ask this, but i'm not sure, guess answers will tell huh?
anyway,when i gave mt big envolope to the 2ond nero, who was a total a**, ub beleivable in his "I don't have time for this," oh(smiled) you smoked?, shrugged his shoulders at questions, smiled again to himself. anyway i did not know there was a report in there too.
He did not take that out, looked at my MRIS and said, well looks like mini strokes, or just spots from smoking,or what ever else too.laughed and said you don't have MS, here a AD, see ya...not really. i found the report later in the envolope,and radiologist wording that really caought my eyes (and heart) said "MS cannot be ruled out at this time"
never said to me, and was never looked at I guess, or what? WHO does one trust,I would think ones who work together? I don't know, and I'm frightened now of my next, new nero appointment, its been 14 months since MRi, ayear since i was told this is just your fibro, three years of suffering pain, and life changing, tho minor, desisions, times of missing out, and sadness.plain and simple,  humming4u ps thanks for just reading my struggle if thats all.
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