I'd take them in reverse order.
Diagnosis of Exclusion: There is no way to diagnose the disease by testing (Clinical, Lab, etc.) so you test for all of the mimics. If it is none of the mimics, then it must be the one disease left.
Lab Diagnosis: If you test blood or CSF for "burgdorferi sensu stricto DNA" and it is positive, then you have Lyme's disease by laboratory diagnosis.
Clinical Diagnosis: Clinical diagnosis means that a medical professional makes a diagnosis based on symptoms and signs (exam, lab values, etc.). So, a clinical diagnosis of MS typically means that they have excluded all the mimics (exclusion,) you may have OC Bands in your CSF and/or a positive VEP (lab evidence) and clinical data (neuro exam, history, etc.
There is also "Differential Diagnosis" which kind of like exclusion. When making a clinical diagnosis they need to consider what other diseases could present the same way and rule them out.
I t really depends on the Neurologists. In my case I had Dawson's fingers on the first brain MRI which is clearly MS acorrding to 4 Neurologists. All my Neurological exams pointed to MS. I had a life time of symptoms. I had been to Neurologists since 1965. I had an abnormal Evoked Potential, Baer, and EMG. Tons of blood work ruled out everything else. Six Neurologists said I would be diagnosed with MS and it took an overwhelming abnormal LP and more blood tests to get a diagnosis. It still took two years. I had five abnormal MRIs over 2 years.
This diagnosis is so convoluted it is stupid in my opinion.
I'm in agreement with you on that opinion. It almost seems MRI has done more harm than good from patient's standpoint. It causes them to rule in or out almost definitively if it doesn't show characteristic changes. When years later, those changes show up, then all of a sudden, oh, you have MS. I wonder how much disability and loss of functionality could be prevented by doing a trial run of DMDs as part of the diagnostic process. Where' the harm in that vs. letting the disease run it's course unchecked while floundering around looking for a label for it?
With the new 7Ts, they're finding changes that happen earlier on that do not show on the 3Ts.
Here's my experience: I've been diagnosed with migraines without MRI evidence or any other kind of evidence, just personal history (which more so indicates MS than migraines). I can get treated for migraines without them actually knowing for sure that's what's happening. If I've had migraines for 20 years (I disagree with the migraine dx as the type of headache I'm getting, btw) where are the lesions on MRI? You would think with that many severe headaches, something would have shown up by now.
Meh. Just moaning. Things continue to progress and show up in new places, it seems to me all that needs to be there to make the call is there, but nobody will. It's aggravating.
Not just the 7Ts, but the use of MT-MRI on the 1.5T units can show changes up to 2 years before lesions form.
Bob, what is an MT-MRI? Is this a new thing?