How MRI's Show MS Lesions

[Quixotic1]

MY QUICK AND DIRTY EXPLANATION OF HOW MRI'S SHOW LESIONS IN MS

I am going to overexplain the MRI with contrast / without contrast thing again, so that you and your husband can have it as clear as possible in your minds.

MS does it's damage by causing the nerves in localized areas in the brain and spinal cord to lose their protective sheaths, called myelin.  At first, when the myelin is being attacked, the body brings a higher blood supply to the area to fight the attack and the area becomes inflamed.  These areas, now become lesions.  At this point they are called "active lesions."   At first the nerves haven't changed much and they appear (and have the same density) as the healthy areas around them.  At this point after some time, probably months, the body CAN repair the damage and remyelinate the nerve.  This repaired nerve still won't be as good as new, but the lesion "looks" like normal brain.  Sometimes later an old scarred lesion will "reactivate" and the adjacent areas will inflame and have increased blood flow.

If the attack on the myelin sheath is too strong for the immune system to repair, more and more myelin disappears and the area of nerves eventually dies.  Then it contracts and scars.  The blood flow is decreased to that area and the area becomes "less dense" then the surrounding normal nerve tissue.  After a longer time - probably years - the scar can reabsorb and the area becomes "empty."  It's called a black hole.

When you image these lesions with an MRI you can see different things, depending on the technique,the age (stage) of the lesion, the power of the MRI, and whether contrast is used.

The first image is done without contrast.  This technique will show old lesions that are big enough to be seen by the power of that MRI machine.  WE KNOW that many lesions in MS are too small to be seen.  If the newer, more powerful MRI with a 3 Tesla magnet is used many more lesions will be seen (by at least 25%) than on the older 1.5 Tesla machines.  The classic old, mature MS lesion is a little bit oval, will have well-defined borders and will be in the white matter.  Characteristic places are subcortical, peri-ventricular and in the corpus callosum.  The classic MS lesion will also have it's long axis perpendicular to the ventricles of the brain.  Also, important and very symptomatic lesions are found in the brainstem, the cervical and the thoracic spine.  The spinal cord ends at the bottom of the thoracic spine, so there is no such thing as a lumbar spinal cord lesion in the normal spine.

These scarred lesions will show up as light, bright areas.  These are the classic, MS lesions or "plaques."

Now the very old, scarred ones that have been reabsorbed will show up as a black (empty) space or black hole.  If there are many of these empty areas the brain will contract around them eventually and show up as a loss of brain volume.  This is also know as brain atrophy.  This is particularly seen in the progressive types of MS.

However, a newly active MS lesion may not show up on a regular MRI because the area of nerves, though inflamed, is still pretty much intact and has normal brain density.  On the MRI it will look like normal brain.  Without contrast it won't show up and will be missed.

When the next phase of MRI is done the contrast is in the blood vessels.  So the large blood vessels show up, too.   Anywhere the tiny blood blood vessels are more dilated than usual, as in inlfammation, the areas will "highlight"  or "enhance."  They show up as even brighter.  So new lesions will show up as enhancing, or active.  Also, older lesions, that have undergone new attack right around them will show an enhancing rim or ring.  When you compare the regular MRI to the Contrast MRI you can see this reactivated, old lesion.

That's how some reports can call active lesions or some report no newly enhancing lesions.  Also since some new ones heal they can be compared to old films and show they disappeared.  In addition, between different sets of MRI done after a time has passed, the radiologist can see an increase in old and in new activity.

Please ask question where I haven't been clear.

Quix

[nicf4]

I am in desperate need of some advice. I am a 38yr old female who has been suffering on and off for years with weird symptoms. However just recently with severe neck pain pins needles sore horrible legs and feet. Dropping smashing and spilling everything. Mri of brain showed many more then 9 lesions in periventricular white matter, but only a small suspected syrinx on c spine. Radiologist put strong consideration of demyelinating plaques. However neuro laughed at me said it was stress and smoking, regardless of pain in crazy spots under my skull big toe jaw patches of numbness blurry left eye leg giving out etc. I dont know what to do.... im not scared but cant ignore the symptoms. She wrote me off. Ive never felt so alone and almost crazy.

[CanCanRun]

Thanks!  That's a great idea. =)

Quix did such an excellent job at explaining what so much of this means - and I hope that she is doing well!

I really wish there was a class we all could take that would walk us through all of the inner workings of this disease. The doctors just don't seem to have enough time to sit down and go through this kind of thing with us in a thorough manner.

[Lulu54]

Hi Cancan, Quix did a lot to get this forum started, but she isn't around here these days because she is busy taking care of herself.  Your question is so good, I am going to copy it and start a new question - hypointensities (black holes) sound horrible and it might help to understand them a bit more.

[CanCanRun]

Anyone have any idea how radiologists differentiate between a "black hole" lesion in an MRI and something else?  I just got a brain MRI last week and the radiologist noted that the lesion on my frontal lobe is unchanged since last MRI... and there are several "punctate foci of hyperintensity in the inferior right frontal lobe" - which, in his opinion, is a "perivascular space" issue.  

I have a black hole lesion on my c-spine, so I know they show up dark in T1 and bright in T2 MRIs, which is exactly how these "foci" are presenting. I even found them in my MRI, before getting the results, because they stood out so much. They are clustered, and directly adjacent to my ventricle, which as I understand it, is a common feature of MS lesions.  I'm not saying these are, in fact, MS lesions, but am curious as to how radiologists tell the difference - and if it really is a judgement call.

[shannon2732]

can u take a look at my MRI? i got Lyme 3 yrs ago, undiagnosed for 2 now have arthritis my hands and legs tremble i get sharp pins and needles in my legs feels like its twitching and before bad weather it acts up and i get a pain and numbness feeling i have constant migrains and the nurse said my MRI looks good but if its at the beginning maybe its to small to see, i feel like i see a couple white patches, small, please e mail me ***@****

[sarahleeann]

Hi,

I have been having strange symptoms in the past 3 months such as different sized pupils, itching all over, tingling in my face, fatigue, ppins and needles in my feet and hands and face, and sometimes in other places on my body, dizziness, panic attacks, fast heart rate, seeing floaters. These symptoms very in severity from day to day. Some days I don't have any symptooms or just a couple sharp pains in my feet.  I have had an MRI with contrast and it was normal. I have seen an eye nero doctor and he said I was normal. Pls give any advise I am woundering if I have ms but my mri was normal.

[CJMC18]

Hi, I know this is old, but what was your outcome?  This is similar to what I’ve been feeling.