MS imaging studies – the wrong approach?
Here’s a thread to kick off the new blog:
Everyone seems to be agreed that we need better imaging markers for MS because clinical measures lack sensitivity and specificity for the disease process(es). But what’s the first thing that one does when he has a new imaging marker to evaluate? He looks to see whether it correlates with clincal measures! Does that make sense? Suppose my new imaging marker correlates PERFECTLY with clincial measures. Wonderful!! My imaging marker’s better than your imaging marker! But wait a minute – if ‘A’ correlates with ‘B’, then ‘B’ correlates with ‘A’ – so what makes ‘B’ any better than ‘A’?? Especially if we already have ‘A’, whereas ‘B’ requires additional effort. Talk me down here! –A. Field
Valerie Jewells, UNC says:February 2nd, 2009 at 11:15 am
Agreed conventional MRI and clinical parameters are woefully inadequate since neither has patho-physiologic sensitivity. The 3-year benefit trial showed that early initiation of B-interferon in clinically isolated syndrome patients led to decreased accumulation of disability, but at the cost of approximately $16,050.00 per CIS patient/ per year which translates into a cost of $400,000.00 to prevent one patient from expanded disability status scale (EDSS) progression. Additionally, the benefit study did not require an EDSS progression of 0.5 steps as is a standard requirement by most clinicians for disease progression since everyone is aware that the test is not very accurate. Neuropsychiatric testing may be more sensitive, but no one advocates its use due to cost of @ $1,200/assessment and limited availability. Therefore, it is evident that to improve early diagnosis and to contain cost that a better method of assessment be developed. Unfortunately, we currently have no other methods of comparison to new imaging parameters than clinical parameters including EDSS and oligoclonal band testing (95% sensitivity at best), as well as conventional MRI. Until we develop a test that assesses response to therapy (allowed by drug companies when patients are on therapy trials) that correlates better with clinical findings than EDSS and conventional MRI, we have to compare to all new imaging modalities available. The solution may actually be in a combination of these new modalities. 1/1000 people in the US have MS, and they deserve a more sensitive and specific answer to their disease process, unfortunately it will likely be a long time coming, and only with significant comparisons of A to B as well as C, D, E, and F will it occur.