Multiple Sclerosis and MRI Basics: Understand Your Brain Scan

Multiple Sclerosis and the MRI: What is an MRI? How does an MRI work? What is meant by a “MRI with contrast?” These and other important MRI fundamentals are discussed.

The MRI stands for Magnetic Resonance Imaging and it's the most useful biomarker currently [2018] available to diagnose MS, monitor disease progression, and assess response to disease modifying therapies. Let's discuss the basics:

What is an MRI?
MRI stands for Magnetic Resonance Imaging. The MRI machine is essentially a really big magnet that can take detailed pictures of fat and water. This is fantastic for brain and spinal cord imaging, because of central nervous system is made up of different types of fats and water!

How Does the MRI Work?
The MRI machine uses a giant magnet is used to send out pulses of radio waves. These waves make the protons found in water molecules within the tissues of the brain become “excited” and “stand up at attention.” Then when the radio pulse is turned off, those excited protons “relax” and slowly fall back down. Different neural tissues cause different “relaxation times,” which result different contrasts between the structures of the brain.
Important safety points: The MRI uses a magnet and has NO radiation and NO X-rays

What is an MRI with Contrast?
The contrast dye is called gadolinium. It is injected into your vein partway during MRI. This dye stays in blood stream and lights up blood vessels. The dye can’t cross the blood brain barrier (BBB) so it doesn’t leak out into the brain tissue. If, however a brain with MS experiences new active inflammation, the BBB becomes “irritated” and gets leaky, allowing the contrast dye to leak out. This results in a gadolinium enhancing lesion.

MRI Basics:
-Scanner Strength: measured in units of Tesla. For MS, you want a 1.5T or 3T scanner. NO, a 0.7T open MRI isn’t ok.
-slice thickness: ideally 3mm or thinner.
-Gap between slices: ideally NO gap.
-Sequences for brain: FLAIR SAG, FLAIR AXIAL, T2 AXIAL, T1 PRE CONTRAST AXIAL, T1 POST CONTRAST AXIAL

Please leave your questions and comments below!

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[AaronBosterMD]

Would you like to see more MRI related content?

[ohmeowzer]

I don’t have MS but I am nurse and came across your videos ..I’ve been a RN for 32 years, ,I didn’t realize how little I knew, ,this will help me understand my patients better

[syazwanimohdsabri]

It's an old video, but I just discovered this. When I saw my brain MRI, the Dawson's fingers have enlarged and I can really see the spaces between the brain tissues at the areas near and halfway near the skull. This makes it easier to understand.

[leilei]

Thank you so much for this VALUABLE INFORMATION!! I have wanted my questions answered for sooo long regarding MRI quality, so thank you Doctor!! I love you videos!

[gabbyfranks]

We need an MRI yearly. What about spinal tap? When are they mandatory for MS?

[susankapur]

What a terrific explanation. Thank you!

[eekeller]

When you go for an MRI, how do you ask that the slices be 1mm, very small gaps, etc.? One is not told before the MRI what the parameters of the MRI will be, so how can the patient demand they be given the optimum MRI, esp. since insurance is not going to pay for multiple MRIs?

[j.m.p]

So great you made that one! I never had it explained and feel this is awesome info!

[ericchamberlin]

Doctor could you please discuss/explain the safety and risks of the contrast materials and also how these materials relate to the frequency of MRI's over time (safety of a specific amount of contrast and MRI exposure for MS patients over the course of treatment)? Thank you. My family and I are learning a lot from your videos!

[garethwilliams]

Thanks Doc, this video was super (as are all the others). One quick question if I may, I had an MRI of the brain and spine recently as I am under investigation for possible MS....radiologist reported a clear scan and I am yet to see my consultant. Can I assume that the issues you raised (thickness etc) may have missed any possible small lesions? Just trying to gather all the info I can ahead of my appointment. Keep up the good work!

[Ollie]

Doctor, thank you. I don't have MS but your explanation of how the MRI works was very interesting to me. I had a brain MRI because of vertigo and a feeling of pressure by my right ear. The scan was essentially normal. I'm saying that because my PCP did not discuss it with me. My question is regarding one of the comments, what does this mean? "Chronic change": advanced degree of confluent T2/FLAIR hyperintense signal in the periventricular white matter most prominent posteriorly. Coexisting involvement of the centrum semivole and subcortical levels. I am 72 and am an active person, flippantly told "just old brain"

[bigchungus]

I'm getting one today so thankyou

[ahmednessim]

dear doctor wanna ask you about my case MRI shows bilateral cerebral white matter foci and two pontine foci of csf is my case Ms

[joannacafaro]

Can you have active MS even if you’re MRI has no obvious enhancing lesions?? And does having an active lesion cause more damage the longer it is active??

[Trevdeclune]

If radiologists really believe gadolinium contrast in the body is safe. Send out the disclaimer documents along with the full name of the contrast weeks prior to the procedure, so patients can make an informed decision at their leisure, as opposed to 5 mins before the procedure. which is absolutely ridiculous. Im guessing most radiologists know of chelated gadolinium risks and would not have it injected in them selves.

[crzyKT]

Dang. Just got an open MRI a couple days ago, still waiting on the results. But not so hopeful they'll give me any meaningful answers now. Oh well.

[Kitty-gkgi]

You have talked before about the thickness in slices on an MRI. I guess my question is, if they are using thicker slices... Say 6mm, would the process of doing the MRI be shorter than if they are capturing 1mm slices? In other words... A brain MRI capturing 6mm slices/images would take less time in the MRI machine than a brain MRI capturing 1mm slices/images??

[nessar]

Hi doctor ! If someone has sclerosis, will you loose muscle mass in the legs thighs ??? Please answer ! Thank you

[itiswhatitis]

Haaay Doctor, please answer, what is the difference between brain leasions and spinal cord leasions 😩😩 ??

[justMe-rdsw]

Dr Boster I'm in the uk, wish I could see you but that is impossible, could you point in the right direction of someone as great over here in the uk, 5 years& counting undiagnosed & sidelined/ forgotten about. Many symptoms which are increasing worsening etc, I'm not saying I have ms but I have many same & similar symptoms & am at the end of my tether just trying to live day to day.