MRI and contrast administration

[cashu17]

I get MRIs (brain, c-spine, t-spine) with gadolinium on a 3T machine at least once a year, sometimes more often if I'm having new symptoms.  I am presently having some new symptoms and my neurologist would like to obtain a scan.

I have had more lesions appear over time but not one in the past five years has enhanced.  I wonder about the technique used at the hospital I go to, there is no time between administration of contrast and the scanning.  I've asked about waiting to start the scanning and have been told it did not make a difference.  In the past, at another hospital I had enhancing lesions on several scans and they did not start scanning until 5 or 10 minutes after the contrast had been given.  

I was hopeful that Bob might help me with my questions.

Does it seem odd that when comparing old scans to new ones, multiple lesions have been noted over time but not one has enhanced in the past five years?  
Should I suspect it is the lack of time between contrast administration and scanning?  I asked my neurologist and he said that in the past it made a difference to delay obtaining post-contrast images for five minutes but it is not longer necessary.  Does that sound reasonable?  

I am coming up on another scan and want to know that the images obtained give as much information as possible, especially when the cost of the scans is considered.  

[sllowe]

Hi Cashu -

Glad you brought this up. We've talked about this at length in the past - but not recently.Here is just one discussion I think you and others will enjoy reading....

http://www.medhelp.org/posts/Multiple-Sclerosis/MRIs-and-gadolinium-contrast/show/1096679

-Shell

[Lulu54]

The sequencing is important to whether the gad is going to light up if the disease is active.  You should double check with your neurologist about the protocol that is being followed with your scans.  I would hope that all the techs know the MS protocol, but we all know how unreliable that can be.  

The question might be what is causing your new symptoms - are they directly related to lesion activity?  

It is also possible that the MRI is not picking up all the lesions - we know that everything is not seen on imaging.

I'm sorry to hear you are having these new problems without a clear understanding of why it is happening - it would be greati f we could capture it all in pictures.

be well, Lulu

[cashu17]

Thanks to both of you for your responses!  

A number of the scans were ordered at the time within days of having new symptoms so I thought that some of the lesions would have enhanced given the timeframe.

I'm going to ask about the order of the sequences following the Gad administration.  If the first scan after the Gad is administered is a T2 scan it is still allowing the time to elapse before the T1 images are obtained.  If not, I'm going to request that they wait five minutes.  I hope that comes across as a reasonable question/request.

Thank you.
Carrie

[COBOB]

They should wait a minimum of 5 min before doing the T1 scans post-GAD.  Some centers will give you the GAD and then do the last T2 scan (which will take more than 5 min) and then start the T1 post-GAD sequences.  Since GAD will only show up on the T1 sequences, this is considered an acceptable procedure and you don't have to wait in the bore doing nothing for 5 min.  

Bob

[jujuminx]

Well, Bob is definately your man for this question.  From what little I know, the enhancing has to do with the age of the lesion, not how long the dye has been in your system.  

It could be that the timing of the MRI's just happen to be after the lesions have been established and aren't "new" anymore (over 60 days?), hence they don't enhance from the dye.

Hope you get more detailed answer to your question.  Good luck.

Julie