A “major advance” could help doctors personalise treatment plans for people with multiple sclerosis, scientists say.

Early MRI scans can predict how the condition will progress, and allow someone to find out how disabled they are likely to become.

The study, published in the journal Brain, followed 164 people with clinically isolated syndrome (CIS) over 15 years.

People with CIS have experienced one episode of neurological symptoms and often go on to be diagnosed with multiple sclerosis (MS).

Dr Wallace Brownlee, who co-led the research, said: “We already use MRI scans to diagnose MS and to monitor the course of the disease.

“These findings – which suggest existing measures, routinely available in clinical practice, can provide a long-term prognosis – are a major advance that will be welcomed by many in the MS community.

“MS can be relentless, painful and disabling, but being able to predict how a person’s MS might progress will mean more certainty, better treatment choices, and hopefully better long-term outcomes for everyone living with the condition.”

Monitoring how the condition developed, researchers discovered that MRI scans from when people were first diagnosed contained signs of future progression.

They found that early spinal cord damage indicated people were much more likely to develop the secondary progressive form of MS, which currently has no treatment and is where disability gets steadily worse.

There was also an association between lesions seen in the brain at the time of CIS, and someone’s physical and cognitive performance later in life.

Dr Susan Kohlhaas, director of research at the MS Society which funded the research, said: “MS damages nerves in your body and makes it harder to do everyday things like walk, talk, eat and think.

“It’s also different for everyone and there isn’t currently a consistent way of predicting what course MS might take.

“This can be incredibly distressing and make decisions about treatment, family and life in general very difficult.

“By identifying key factors that appear very early on and indicate how someone’s MS might develop, this study has proved crucial.”

After the 15 years, all participants had their disability assessed using measures including the expanded disability status scale (EDSS).

Ninety-four of them (57%) had the relapsing form of MS, 25 (15%) had the secondary progressive form, 45 (27%) remained CIS and two people (1%) had developed other disorders.

Scientists say knowing how someone’s condition might develop will help healthcare professionals personalise treatment plans.