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

[essdipity]

Why did she have the first MRIs 10 years ago?

[essdipity]

Well, how can you be sure she doesn't have MS? Have you considered that the reason she hasn't had flares or worsening symptoms may just be that the Avonex has worked amazingly well?

By the way, Avonex is not available in pill form, and no pill treatments for MS have been marketed for more than a couple of years. Please re-check with her regarding the treatment she's on.

ess

[Arsi88]

More than 10 years ago a neurologist told my sister she has MS based on the MRI of the brain she did back then. The doctor said she sees plaques in her brain that represents MS and she has been taking Avonex Pills all these years, though she has NO symptoms of having MS whatsoever. She does MRI of the brain, CT of spinal cord, eye exam, coordination exam, blood work and any other exam that you can think of every year and every time EVERYTHING comes out normal (the MRI still shows the Plaques but not a single plaque has been added since 2004). we are just wondering if she really doesn't have MS and the doctors have made a mistake in diagnosing the disease just based on the MRI results. We really need help of what we need to know to prove that she doesn't have MS.

[Jlynn54]

I am unable to have any more MRIs due to a Pacemaker.  So how can my neurologist tell my MS isn't active slowly progressing when all he does is check my reflexes.  It's quite frustrating.  He has ordered CT scans, but apparently they don't show anything. Help....what should I do or say

[immisceo]

Hi rt66gv. A couple of things here; Quixotic1, a great resource to the community, is no longer actively participating on MedHelp. She would not likely see your message.

Secondly, this is a patient-led forum. There are no doctors here, at least in the relevant area. Also, giving this kind of information/advise in the manner you mention (via email) would questionable in the ethics area. A neurologist needs to see you in person in order to assess how the MRI imaging fits into your physical presentations.

However, if your scans came with a radiologist's report, we do have some members here who have a knack of turning 'doctor-speak' into 'plain-English' if you're having trouble understanding the findings.

Here we can give pointers, a sounding board, support and personal experiences, but we can't diagnose.

Perhaps you could go back to the MSAA (I assume you mean the Multiple Sclerosis Association of America) and they can give you information about neurologists that accept pro bono work or alternative sources of helping fund some professional assessments. Perhaps others here can give feedback on that as well.

[rt66gv]

I have no income or insurance, but the MSAA paid for a cranial MRI as I have almost all of the symptoms of MS. If I could email you the scans, could you help interpret them? I'd appreciate it if you could. Email: ***@****