I think you're right in your assumptions. Honestly, I don't think that they can find areas of active demyelination without contrast. Otherwise they would just see lesions. (I think..) But I am not a doctor or radiologist.

Maybe someone else has an answer..

(this was really just a reply to bump your question up)

Don't know, is there something unrelated to MS they are doing it for, something they might be looking for that would not require contrast? Otherwise, I woulld say, mistake. But ask. And maybe you will get the chance if they have to do another one, with contrast.

It was supposed to be without contrast only. Guess the doctor wasn't too worried about new lesions!

I think the contrast is very important for diagnosing MS because an active lesion diagnosis MS---but once diagnosed it is perhaps less important to use contrast at every MRI----

The contrast shows if the lesion is active--a lesion remains active for about 30 days on average. An MRI is a single snap shot in time. The non contrast shows lesions that exist and had to have been active before--- it gives the history of what MS has been doing since the last MRI

An person with MS will have 10-15 asymptomatic lesion a year. Neither the doc nor the MS person knows they are there. If the MRI just happens to be done when they are active the MRI will catch it.

Recently I read a post from someone with a radiology background written to someone with financial difficulties and he said get the non contrast MRI if you have to select one its the more important one.

I understood what he said, but she was also undiagnosed so I hope she was able to scrape up the $ for the contrast one too, because if 1 active lesion showed it would give her resolution on what is happening with her. All inactive lesion would just give possibilities of what could have caused them, with MS being one of the possible causes.

The contrast will also show black holes in more advanced MS--but that is not something that need to be checked at every MRI.

Evolution of a lesion:
1.FIRST--- For a few hours, day, or weeks(variable), a lesion will "highlight" on the non contrast T2 MRI. It won't show at first with contrast--or it may show a black dot that is easily missed.
With contrast it will be as if a lesion is not there- it won't show.

2. SECOND:The contrast then begins to show the active state of a lesion for a few weeks, average a month, or a few months. At this time it will enhance with the contrast. At this time it BOTH enhances with contrast on T1 MRI and highlights without contrast on T2.

In cases of more advanced MS it may show a black hole with the dye.--I forget the word opposite of highlight or enhancement?

But always the lesion will show highlighting on the T2 without dye.

3. THIRD: The contrast stops showing enhancment after a few weeks or months (1 month on average) on the T1 MRI, its shows no lesions, as if nothing was there on the T! with contrast. It still highlights on the t2 without contrast. Throughout the entire process it continues to highlight without contrast.

4.FOUR: It continues to show highlighting on t2 MRI. The lesion can get bigger, smaller, stay the same size or become unmeasurable by the MRI & not show at all.

The non contrast MRI shows more lesions and if they have gotten larger or more of them, then they had to have been an active before. The MRI is just a snapshot in time and it might not have been taken when it was active but the hilghting lesions that remains shows that it was active before.

At times I think when MS is not certain, an MRI without contrast will be ordered as an investigation to determine if further investigation is needed. The problem is if lesions are found there is a limited amount of time to catch the active state with an MRI with contrast. Which may be needed for diagnosis.

It seems reasonable that you had an MRI without contrast after the cause has been determined, the MRI without contrast shows what your MS has been doing since the last MRI-better than with contrast would have done.

In math, think integral versus derivative. Without contrast the MRI is more like an integral show behavior over time with contrast its more like a derivative-showing a snap shot in time.


That reasoning is practical, IF diagnosed--different reasoning if not yet diagnosed. Contrast is more important then.

And black hole status, the status of black holes is not needed as frequently--but if its a black hole it has BOTH the T! contrast black hole and a corresponding t2 non contrast lesion.