MRI for monitoring response to MS disease-modifying therapies

Topics for discussion:

• BSNR guidelines on MRI for multiple sclerosis
• Dealing with common questions about MRI scans from patients
• Why am I not having a spinal cord MRI?
• Why did they not give contrast dye with my MRI?
• If my MRI scan is stable then why do I feel worse?
• Practical solutions for addressing challenges in MRI monitoring (e.g. capacity, access to neuroradiology, re-baselining, lesion detection/AI)

Webinar summary

Monitoring response to disease modifying therapies (DMTs) in MS is one of MRI’s most useful functions.

“Change in MRI helps us decide whether the treatments we offer patients are working or not,” said Dr Wallace Brownlee, consultant neurologist at University College London Hospitals NHS Foundation Trust, adding that people who have ongoing MRI activity and relapses while taking DMTs have worse outcomes.

“People who are relapse free but have relatively small changes on MRI will do worse than people whose MRI scans were stable. We know also that escalating treatment on the basis of MRI activity, rather than waiting for relapses, is associated with more favourable outcomes.”

BSNR guidelines on MRI for multiple sclerosis

The British Society of Neuroradiologists (BSNR) and the Association of British Neurologists (ABN) are currently developing guidelines which aim to standardise MRI.

“Most people who work in MS will know there is much variation in how patients are scanned,” said Dr Audrey Sinclair, consultant neuroradiologist at St George's University Hospitals NHS Foundation Trust, explaining that this variability delayed management decisions.

The guidelines, she went on, will specify the timing of MRI, and which planes and sequences to use.

IN RRMS, the guidelines recommend a re-baseline scan, or brain and cord, at six months post-diagnosis, and “in an ideal world”, annually thereafter. “However, we have to be pragmatic and do what we can based on the resources we have,” she said, adding that cord scans in those with no evidence of cord disease could be performed less frequently. Re-baseline scans should also be conducted early post-partum, when disease tends to become unstable, though this is not always possible, and before switching treatments.

In progressive disease, MRI is predominantly used to demonstrate disease activity for treatment eligibility. This is often challenging because a lot of patients will not have recent imaging for comparison. When this is the case, it can be useful to demonstrate a gadolinium-enhancing lesion, said Audrey.

In terms of brain sequences, Audrey described 3D FLAIR as the “bread and butter”. Compared to 2D FLAIR, it offers superior quality, resolution, and lesion conspicuity. “A good quality 3D sequences mitigates the need for giving gadolinium in follow-up and additional T2 sequences.” Diffusion weighted imaging (DWI) can be useful in monitoring for progressive multifocal leukoencephalopathy (PML), and the volume T1 is useful for looking at volume changes over time.

In cord MRI, centres should acquire both sagittal and axial images to ensure no lesions are missed.

Scan readers are predominantly looking for new and enlarging lesions, as well as other markers of disease activity, such as leptomeningeal enlargement or chronic inflammation, or signs of treatment complications. These might include opportunistic infections, tumours, or ischemic lesions.

“An important part of monitoring is the MDT. A regular MDT with access to neuroradiology input gives you a much better quality of decision making,” said Audrey.

Dealing with common questions about MRI scans from patients

Liz Woodhead, clinical nurse specialist in multiple sclerosis at Sheffield Teaching Hospitals Foundation Trust, shared her advice on dealing with common questions patients may have about their MRI scans.

Why did they not give contrast dye with my MRI?

Common reasons include pregnancy or breastfeeding. In addition, contrast may not be used during a routine DMT or PML monitoring scan where the patient is not experiencing symptoms because activity may not be expected, she added.

Audrey said that gadolinium accumulation did occur, and while there was no evidence of harm as yet, “we use it when we need it”. “In the monitoring of MS, by and large we do not need it.”

Why am I not having a spinal cord MRI?

Firstly, a spinal cord MRI is not needed for DMT or PML monitoring, as the brain is the area of interest.

In general, the decisions will be made based on clinical signs and symptoms, and Wallace said that most cord lesions caused symptoms. Audrey added that there was data to suggest people could develop asymptomatic cord lesions, but these tended to be accompanied by new brain lesions. It is about capacity, and being pragmatic in selecting the most appropriate patients for cord imaging, she added.

Where are my lesions and how many do I have?

“I think it is really useful for patients to see their scans,” said Liz, adding that this could help people to make decisions about DMTs. “You want them to have all the facts so they can make a decision; I wouldn’t want anyone to look back and regret not going on treatment when it was offered to them.”

Audrey said she tried to give people “a ballpark figure” of the number of lesions. “I also think it is important to talk about the location of the lesions. We know for example that infratentorial lesions and cord lesions are more highly linked to disability, so I think that plays into the decision making.”

If my MRI scan is stable, why do I feel worse?

Lots of other things could be going on, said Liz, including background MS symptoms, neuron loss, or atrophy, or progression.

Our MS Academy webinars are available on SoundCloud:
soundcloud.com/neurologyacademy