International MRI Guidelines Offer Standardized Approach to Improving Diagnosis and Patient Care in Multiple Sclerosis

Errors in MRI technique continue to occur if the imaging facility does not employ current protocols specific to MS. To guide clinicians and patients, the CMSC has developed concise summary cards that patients can take to an MRI appointment. These cards are available from the CMSC in English or Spanish. Cards may be downloaded from the CMSC’s web site at www.mscare.org/page/MRI_protocol.ORLANDO, Fla. – Among the most essential and clinically useful messages from this week’s Consortium of Multiple Sclerosis Centers (CMSC) Annual Meeting was the presentation of the 2021 update of magnetic resonance imaging (MRI) guidelines for multiple sclerosis (MS). For MS clinicians, receiving MRI images that fail to follow the latest protocols could lead to missing the diagnosis, overlooking important features of the disease, or the need to repeat the test entirely.

The latest 2021 consensus statement for use of MRI in MS diagnosis and treatment represented an international collaboration between the CMSC, Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS), and North American Imaging in Multiple Sclerosis (NAIMS). A panel of experts instrumental in authoring this guideline statement presented at Monday’s symposium, including David Li, Anthony Traboulsee, Jiwon Oh, Mike Wattjes, and Scott Newsome.

The 2021 guidelines for brain MRI suggest:

• Magnet strength of at least 1.5 Tesla must be used, but 3T is recommended when available;
• Core sequences should include T2 weighted 3D fluid-attenuated inversion recovery (FLAIR), axial T2-weighted, and T1-weighted images with gadolinium;
• 3D acquisition is preferable for FLAIR and T1-weighted sequences to improve lesion detection and contribute to better realignment of anatomic orientation on serial scans;
• Pre-contrast T1 weighted sequences are not required.

The guideline update also helped to clarify the benefits of spinal cord imaging in MS diagnosis, “Spinal cord pathology is crucial in MS diagnosis and can be beneficial in the differential diagnosis between MS and vascular disease,” said Mike Wattjes, MD. For imaging the spinal cord, 3-Tesla scans do not offer a particular advantage over 1.5 T scans. However, the guidelines suggest imaging the whole cord, not just the cervical segments, to detect lesions in the lower thoracic spinal segments (seen in about 20% of patients with MS). To avoid longer acquisition times, a compromise might be to image the upper half of the cord (C1 to T5) since few patients with MS have lesions exclusively located below T5, Dr. Wattjes said. Prognostically, spinal cord imaging has been used to predict long- and short-term disability and conversion to secondary progressive disease. Thus far, there is limited value of spinal cord MRI for monitoring of treatment efficacy.

Dr. Oh addressed the growing interest in the central vein sign as a potential biomarker in MS. The presence of this vein, detectable inside white matter lesions on 3T MRI, has been proposed as a biomarker of inflammatory demyelination that could help to distinguish between MS and non-MS lesions. The 2021 guidelines do not yet recommend using the central vein sign, Dr. Oh said, but this could be addressed in future guidelines when additional data are available.

Routine use of gadolinium (Gd) is another issue of interest. To limit possible accumulation, standard Gd doses are recommended in select circumstances, but not double or triple doses. These situations include:

• to demonstrate dissemination in time on a baseline diagnostic MRI
• to contribute to differential diagnosis based on the pattern of enhancement
• to predict future disease activity and potential for disease progression
• to identify disease activity for phenotyping patients with progressive disease

The value of having an international collaboration to present standardized protocols for brain and spinal MRI could not be overstated, the panelists concluded.