The McDonald criteria does not even require confirmation with a MRI or spinal tap, although most neuro's would lead you to believe otherwise.

According to the revised 2005 McDonald criteria , all a MS diagnosis really requires is "objective evidence of lesions disseminated in time and space”.

The very simplest evidence of that would be a doctor witnessing two attacks, with a 30 - 90 day break (dissemination in time), affecting two different areas of the CNS, ie. spinal cord one time, ON the next (dissemination in space).

Using myself as an example, a MRI and/or spinal tap was not necessary for the dx as I had “clinical evidence” of two attacks, and of having two lesions. The way they assessed that (without doing a MRI) was by my doctors witnessing two attacks over separate years (proof of dissemination in time) combined with clear evidence that I was affected in two different ways; once from the chest down, the other time from the ears down (proof of dissemination in space).

HOWEVER, accumulation of that “clinical evidence” can take many years, so if I/they had wanted to pursue a dx earlier, they would have had to add in the use of a MRI (and/or spinal tap) to try to prove “visual” evidence of lesions (or positive CSF/O-bands).

In the table below, “Clinical lesions” (WITHOUT the use of a MRI) are defined as evidence/witness of multiple lesion involvement (two areas of the CNS affected). Where there are less then two clear attacks, and/or less then two areas of the CNS involved, they then move onto the additional “requirements for diagnosis of MS”.



It’s when they have to move onto “additional requirements” that things get complicated. For example, if a person has two attacks, but is affected the same way in each one (no dissemination in space), they will usually do a MRI. At least 3 out of 4 of the Barkhof criteria need to be present to fullfill the MRI criteria for MS, as per the the table below:



If that doesn’t give them what they need, sometimes they will do a spinal tap to see if we have a “positive” CFS (usually defined as two or more O-bands).

When a patients presents with only one symptom that could be a first presentation of MS (possible MS), sometimes a follow up MR is needed to prove that there is also dissemination in time in order to fullfill the McDonald criteria.

The table on the below summarizes the MR criteria for dissemination in time. Another way to prove dissemination in time is to await a second clinical attack.



http://www.radiologyassistant.nl/en/4556dea65db62

Relying mostly on a MRI isn't such a good idea anyway:

http://www.medpagetoday.com/Neurolog...erosis/dh/2929

Cherie