New MRI method enhances early detection of multiple sclerosis, researchers find

Mul­tiple scler­osis (MS) is a neur­o­lo­gical dis­ease that usu­ally leads to per­man­ent dis­ab­il­it­ies. It af­fects around 2.9 mil­lion people world­wide, and around 15,000 in Switzer­land alone. One key fea­ture of the dis­ease is that it causes the pa­tient’s own im­mune sys­tem to at­tack and des­troy the my­elin sheaths in the cent­ral nervous sys­tem. These pro­tect­ive sheaths in­su­late the nerve fibres, much like the plastic coat­ing around a cop­per wire. My­elin sheaths en­sure that elec­trical im­pulses travel quickly and ef­fi­ciently from nerve cell to nerve cell. If they are dam­aged or be­come thin­ner, this can lead to ir­re­vers­ible visual, speech and co­ordin­a­tion dis­orders.

So far, how­ever, it hasn’t been pos­sible to visu­al­ise the my­elin sheaths well enough to use this in­form­a­tion for the dia­gnosis and mon­it­or­ing of MS. Now re­search­ers at ETH Zurich and Uni­ver­sity of Zurich, led by Markus Wei­ger and Emily Baads­vik from the In­sti­tute for Bio­med­ical En­gin­eer­ing, have de­veloped a new mag­netic res­on­ance ima­ging (MRI) pro­ced­ure that maps the con­di­tion of the my­elin sheaths more ac­cur­ately than was pre­vi­ously pos­sible. The re­search­ers suc­cess­fully tested the pro­ced­ure on healthy people for the first time.

In the fu­ture, the MRI sys­tem with its spe­cial head scan­ner could help doc­tors to re­cog­nise MS at an early stage and bet­ter mon­itor the pro­gres­sion of the dis­ease. The tech­no­logy could also fa­cil­it­ate the de­vel­op­ment of new drugs for MS. But it doesn’t end there: the new MRI method could also be used by re­search­ers to bet­ter visu­al­ise other solid tis­sue types such as con­nect­ive tis­sue, ten­dons and lig­a­ments.

Quant­it­at­ive my­elin maps

Con­ven­tional MRI devices cap­ture only in­ac­cur­ate, in­dir­ect im­ages of the my­elin sheaths. That’s be­cause most of these devices work by re­act­ing to wa­ter mo­lecules in the body that have been stim­u­lated by ra­dio waves in a strong mag­netic field. But the my­elin sheaths, which wrap around the nerve fibres in sev­eral lay­ers, con­sist mainly of fatty tis­sue and pro­teins. That said, there is some wa­ter – known as my­elin wa­ter – trapped between these lay­ers. Stand­ard MRIs build their im­ages primar­ily us­ing the sig­nals of the hy­dro­gen atoms in this my­elin wa­ter, rather than ima­ging the my­elin sheaths dir­ectly.