Interval New Lesions

I was diagnosed with RRMS two years ago and am on Tysabri. Since being on Tysabri I have had no new lesions. I’ve recently had an MRI and today received a copy of the results sent to my GP. No sign of PML (great news) but it says “The mri on the brain showed interval new lesions”. I need to phone the hospital to find out what this means. But I’m now worried. Does anyone know what this means? Thank you.

Hi L18

A lesion is a scar caused by demyelination.

MS is an auto immune disease meaning that our immune system eats away at the fatty coating (myelin) on our nerves. It ends up looking like electrical wiring with the protective cover damaged.

Basically it is a fault with our wiring. It helps me understand the weird stuff that happens.

So the 2 new lesions are 2 new scars.

Talk to your neuro or MS nurse if you think it will help.

I don’t understand what the “interval” means though.

maybe the time between this latest MRI and your previous one?

carole x

Hi Carole. Thank you so much for your speedy reply. Yes it’s the “interval” bit I don’t understand either. I’ve had lesions previously as I’ve had 3 relapses. But I don’t get the interval part. Quite upset I have new lesions, as in previous MRIs I haven’t had any new ones for a while.

I wonder if ‘interval’ means that lesions have developed in the interval since your previous mri scan?

I think a lot of people have brain lesions without being aware of them - the lesions only found by chance at an autopsy.

Not sure if it’s a case the more lesions you have the more disabled you are.

Also wondered if the neuros by identifying the position of a lesion can link that to a disability in a certain area?

Also do lesions repair themselves so that if we’re in remission we have fewer lesions than when we have a relapse?

(sorry more questions than answers!)

I suspect you’re right about the meaning of ‘interval’ Cracowian. Meaning the interval between the last MRI and the current one.

I don’t believe the number of lesions relates to disability. Some people have lots of lesions but little physical disability, although they could have insidious symptoms like cognitive damage.

I believe the location of lesions relates to where the damage affects the individual. So if in position (A) a person may have foot drop, in position (B) hand problems and (C) ON or other eye issues. Also, spinal lesions are more likely to affect lower limbs so someone with lots of spinal lesions might be more likely to have mobility problems.

A lesion is a scar, so I doubt very much whether they repair themselves exactly. If you have RRMS, the point at which you have an inflammatory attack, or relapse, the lesion(s) are going to show brilliant white flares of demyelinating activity, when remission happens, the inflammatory flares won’t be apparent on MRI, but the scars will still be there.

So, for example, I was recently (not long before Lockdown!) in an appointment with a neurologist who was looking through my MRI scan and comparing old scans/lesions with newer. So he was (mumbling) saying ‘ah yes, that looks new …oh no there it is, so that ones older’, and just occasionally ‘oh that ones definitely new’.

So it appears that on my brain scan he could definitely tell what was new and what was old. The old lesions still showed up but as scars rather than active current lesions. I’ve also in the past had MRI scans just as relapses began, when the inflammatory demylinating activity was highly evident.

Weird things lesions. Weird people neurologists.

This is entirely my thoughts and beliefs, I don’t know any actual answers regarding lesions, their placement or history. Just a view from my own perspective.


My neuro fully understood when I told him that I cannot regulate my body temperature.

On hot days I shiver and pile on layers of clothing.

On cold days I sweat and act the way other people do on hot days.

I described it as a thermostat on the blink.

He said that’s your MS affecting your hypothalamus and that it was an excellent description.

This was after having almost 2 years of remission.