MS Diagnosis: McDonald Criteria and Gadolinium

June Halper, MSN, APC-C, MSCN, FAAN: Getting to that though, we’ve watched the evolution of the diagnostic criteria from Poser to McDonald. Of course, everybody at the beginning said MRI [magnetic resonance imaging] is not diagnostic, and now look what’s happened. Tony, how do you think these proposed changes are going to help? Because there is a lot of misdiagnosis of MS [multiple sclerosis]. We know that now, in a couple of papers, Dr Andrew J. Solomon, MD, just recently presented at ECTRIMS [European Committee for Treatment and Research in Multiple Sclerosis]. But the question is how can we firm up the diagnosis by teaching people how to use the McDonald criteria and MRI appropriately? This is because it’s certainly not happening in this country with 25% misdiagnosis.

Anthony Traboulsee, MD, FRCPC: It’s important to realize MRI is not diagnostic. It’s supportive of the diagnosis. It has been the appropriate clinical context when we’re interpreting the MRI. Where some of the misdiagnoses have occurred is when the criteria were applied without the accurate or the appropriate clinical symptoms for the patients. The criteria really developed in the classic syndrome, what’s called a clinically isolated syndrome of optic neuritis or transverse myelitis and applying it to that population is highly accurate in terms of making that early diagnosis.

One thing all of us have emphasized in our different publications and guidelines is when the patient’s profile is a little atypical, you must be much more cautious when applying these criteria and collect more information such as spinal fluid analysis or monitor the patient over time. But what’s nice about the MRI protocols that have been developed is they’re perfect for applying the McDonald criteria. They include sufficient quality to detect dissemination of space and dissemination of time with the characteristic lesions, as well as the enhancing lesions. So, it’s the perfect protocols for making that early diagnosis.

June Halper, MSN, APC-C, MSCN, FAAN: One thing I loved when I was in the clinical area is how we spelled out how the report should read, and that’s something we had laid out for the report, not just MS, which is something that people were confronting. Of course, the radiologists are not supposed to make the diagnosis, but I think our guideline hopefully will help guide that diagnostic process back to the neurologist where it really belongs.

Anthony Traboulsee, MD, FRCPC: Yesterday we were also talking about how using contrast gadolinium could increase the efficiency of using MRI diagnosis. I don’t know if David or Frederik wants to comment on that. But it does make it a lot faster only needing 1 scan.

Frederik Barkhof, MD, PhD: Yeah, to make a diagnosis. By showing multiple lesions in various compartments of the brains, so you have subcortical, periventricular, infratentorial… at least you show the dissemination in space. But, if 1 of those is enhancing, you know it’s a recent lesion, and the others are old. So, by definition, you have the dissemination in time just with 1 single scan that you can proceed to treatment decisions if you think that’s relevant.

Scott D. Newsome, DO, MSCS, FAAN: Yeah, and that’s without having to do a lumbar puncture. What I like about the new guidelines, the McDonald criteria, is that different from the old criteria, if you have an enhancing lesion that is the symptomatic lesion, you can make a diagnosis.

Frederik Barkhof, MD, PhD: That was something that caused an enormous amount of confusion. What is the symptomatic lesion? It’s often difficult to determine.

Scott D. Newsome, DO, MSCS, FAAN: Yeah.

Frederik Barkhof, MD, PhD: We got rid of that because after the last iteration of the McDonald criteria, a lot of research was done to see where it made a difference, and in fact it doesn’t. That simplified things a lot. It’s makes it much easier to assert in the dissemination in space and time.

David Li, MD, FRCPC: It definitely reinforces the earlier discussion that we had about the use of gadolinium. Everything that we do is always a balance between risk and benefit, and we are obviously wanting to be sure that the gadolinium deposition is not producing any problems with it. But the opposite side of not using gadolinium is you have the risk of missing the diagnosis earlier of the disease. It’s always that balance that we have to work with and certainly, this is a case where by showing the gadolinium enhancement on that early scan, you can make that diagnosis on that very first scan.

June Halper, MSN, APC-C, MSCN, FAAN: Yeah. The 1 challenge that I remember clinically was that the radiology units would say, “I don’t want to wait for that delay,” because sometimes in our original…I think we haven’t changed it. Once you inject, there has to be a little time before you rescan them and the units say, “We don’t have that time. We want that patient on and off the table.” It’s going to take a lot of education like this program to convince people that gadolinium has value. Unfortunately, time is money in many of those units. We still have a job to do to get out there and educate, and I guess today is day 1 of re-educating people out there.

David Li, MD, FRCPC: I was just going to interrupt, June.

June Halper, MSN, APC-C, MSCN, FAAN: Yeah, go ahead.

David Li, MD, FRCPC: The issue about the time between that we have to wait for the gadolinium is solved in that now we recommend that during that time that you’re waiting the 5 to 10 minutes, you can actually do other sequences. For example, the FLAIR [fluid-attenuated inversion recovery] sequence that is indispensable for the use that we have, most commonly is done during that time between injection and when you actually do the post-gadolinium scan. In fact, my experience, I would be interested to hear what you say, but very often the enhancement is very clearly seen on the FLAIR scan, and it makes it even more confident because you have 2 scans that show the enhancement.

Frederik Barkhof, MD, PhD: I agree.

June Halper, MSN, APC-C, MSCN, FAAN: Well, that’s why we need education because people think you may have to take the patient, let them wait, and if you can do the FLAIR and use it, viewers out there are going to hear this. So that’s important and probably should be in the printed version of this. We need to disseminate this more because the technologists really are not exposed to education the way that neuroradiologists are or the radiologists. They’re just handed a prescription with the guideline, and they say, “Whoops, it’s too much time.”