Friday, 30 March 2012

Voxelwise MRI and disability


Background: The ability of conventional MRI to predict subsequent physical disability and cognitive deterioration after a clinically isolated syndrome (CIS) is weak.

Objectives: This study investigated whether conventional MRI changes over 1 year could predict cognitive and physical disability 5 years later in CIS. The researchers performed analyses using a global approach (volume and number of lesions), but also a topographic approach (where the lesions were).

Methods: This study included 38 MSers with a CIS. At inclusion, 10 out of 38 MSers fulfilled the 2010 revised McDonald's criteria for the diagnosis of MS. EDSS evaluation was performed at baseline, year 1 and year 5, and cognitive evaluation at baseline and year 5. T(2)-weighted MRI was performed at baseline and year 1. They used voxelwise analysis (similar to pixels) to analyse the predictive value of lesions location for subsequent disability.

Results: Using the global approach, no correlation was found between MRI and clinical data. The occurrence or growth of new lesions in the brainstem (area of the brain linking the cerebral hemispheres to the spinal cord) was correlated with EDSS changes over the 5 years of follow-up. The occurrence or growth of new lesions in cerebellum, thalami, corpus callosum and frontal lobes over 1 year was correlated with cognitive impairment at 5 years.

Conclusion: The assessment of lesion location at the first stage of multiple sclerosis may be of value to predict future clinical disability.



"This study shows two things: (1) damage occurs early in MS; it is there at the CIS stage and progresses within the first 5-years. This is at a stage when most MSers don't look or feel disabled. The reason for this is  that the brain copes and adapts to early damage. (2) the localization of MS lesions are important; lesion in the brainstem are more damaging than elsewhere. The brain-stem is a vital structure with a high-density of nerve fibres, so this result is not surprising. The natural conclusion of this study is that we should treat MS early and aggressively to stop new lesion formation and the sub-clinical accrual of damage that occurs with an increase in lesion volume and number early in the disease. Some people will argue against this strategy and will quote literature saying MRI activity does not correlate with disability. This may be true, but that is because these studies used conventional MRI. When you start looking at where the lesions develop, as in this study, the results are different. I strongly believe that we need  to at least allow MSers the choice to have early aggressive treatment, despite the uncertainty about long-term outcomes. If MSers are well informed about MS and DMTS, including their potential benefits and risks, they are in the best position to decide for themselves. Not all MSers are risk-adverse, we need to realise that. If an MSer is risk adverse we also have to respect  that position. There is no right or wrong; we need a personalised approach. "

2 comments:

  1. Any particular reason why the spinal cord was left out?

    ReplyDelete
  2. Re: "Any particular reason why the spinal cord was left out?"

    The spinal cord imaging is complicated and I am not sure if the anatomical resolution is good enough to draw conclusions. It also classified as an additional region, i.e. an extra set of scans, which almost doubles the costs of the study.

    ReplyDelete

Please note that all comments are moderated and any personal or marketing-related submissions will not be shown.