Suspected multiple sclerosis or first demyelinating event
MAGNIMS-CMSC-NAIMS consensus (2021, 2024); McDonald criteria 2024 revisionA diagnostic study whose whole purpose is to satisfy formal criteria, which makes the protocol non-negotiable: specific sequences, specific coverage, and a contrast decision that answers dissemination in time rather than reflexive practice.
A first clinical episode compatible with demyelination — optic neuritis, a partial cord syndrome, a brainstem syndrome — where the question is whether lesions are disseminated in space and in time.
Referenced decision support — confirm against your local protocol.
Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.
Accept as requested
MRI Brain — demyelination / multiple sclerosis
MRI Brain
What we'd amend, and why
- The diagnosis rests on lesion location — periventricular, juxtacortical or cortical, infratentorial, spinal cord — and on the co-existence of enhancing and non-enhancing lesions. Each of those is a protocol requirement rather than an interpretive skill: juxtacortical and cortical lesions need high-resolution FLAIR to be seen at all, infratentorial lesions need coverage that many routine brain studies truncate, and dissemination in time on a single study needs gadolinium. A general brain MRI reported as showing white matter lesions cannot support or exclude the diagnosis.
Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.
How was this decided?
- pathwayadult — Adults
- rulerule-mr-device-screening — MR safety screening for implants and foreign bodies; checked by Radiographer at the scanner
- rulerule-contrast-reaction-premed — Prior contrast reaction and elective premedication; checked by Nurse before the scan
- rulerule-gadolinium-renal — Kidney function and gadolinium-based contrast; checked by Radiographer at the scanner
- rulerule-paeds-sedation — Sedation or anaesthesia for a child; checked by Nurse before the scan
- rulerule-pregnancy-gadolinium — Gadolinium in known or possible pregnancy; checked by Radiographer at the scanner
- rulerule-iv-access — Intravenous access adequate for the planned injection; checked by Radiographer at the scanner
Decision support only. Local protocol takes precedence.
Handled at the scanner(2)nothing for you to do
Settled and owned downstream. Each returns to a radiologist only on the stated trigger.
- MR safety screening for implants and foreign bodiesComplete the MR safety questionnaire, verify implant labelling and its stated conditions of use against this scanner and this protocol, and ensure no ferromagnetic object enters Zone IV.Radiographer at the scannerBefore the scanFlags back if: An implant or retained foreign body that is MR Unsafe, unlabelled, or cannot be identified; or an MR Conditional device whose stated conditions this scanner or the requested protocol cannot satisfy; or a credible unexcluded intraocular metallic foreign body history.
- Intravenous access adequate for the planned injectionSite and test a cannula that supports the protocol flow rate, preferring an antecubital or large forearm vein, and observe the injection for extravasation. A 20-gauge or larger cannula is preferred for flow rates of 3 mL/s or more.Radiographer at the scannerAt the scannerFlags back if: No cannula can be sited that supports the protocol flow rate — for example only a 22-gauge hand or foot cannula for a CT angiogram needing 4–5 mL/s; or the only available access is a central line or port that is not labelled power-injectable; or an extravasation occurs.
Pathways
Big forks are separate pathways; the first whose conditions match is the one used.
Adults
Matches your inputsDefault| Role | Study & protocol | Why this answers the question |
|---|---|---|
| First line | MRI Brain MRI Brain — demyelination / multiple sclerosis usually appropriate | The diagnosis rests on lesion location — periventricular, juxtacortical or cortical, infratentorial, spinal cord — and on the co-existence of enhancing and non-enhancing lesions. Each of those is a protocol requirement rather than an interpretive skill: juxtacortical and cortical lesions need high-resolution FLAIR to be seen at all, infratentorial lesions need coverage that many routine brain studies truncate, and dissemination in time on a single study needs gadolinium. A general brain MRI reported as showing white matter lesions cannot support or exclude the diagnosis. |
| Second line | MRI Whole Spine MRI Spine — myelitis / inflammatory cord disease | Cord lesions count towards dissemination in space and are frequently clinically silent, so imaging the cord adds diagnostic information even without cord symptoms. It is also the most useful discriminator in an older patient, where non-specific cerebral white matter change is common and demyelinating cord lesions are not. |
Pitfalls
- Booking a routine brain MRI instead of the demyelination protocol, which truncates infratentorial coverage and misses juxtacortical lesions.
- Over-calling non-specific white matter hyperintensities in a patient with vascular risk factors. Morphology and location matter more than count.
- Omitting cord imaging in an older patient, where it is the sequence most likely to resolve the differential.
- Attributing longitudinally extensive cord lesions to multiple sclerosis — that pattern points towards neuromyelitis optica spectrum disorder or MOG-associated disease and changes treatment entirely.
- Adding gadolinium to routine surveillance in established disease, where it rarely alters management and accumulates exposure over a lifetime of monitoring.
Priors — what to pull first
- Any prior brain MRI is diagnostically load-bearing: a new lesion compared with an earlier study establishes dissemination in time without needing contrast.
- Align the new study with the geometry of the previous one where possible, because lesion counting across differently angled acquisitions is unreliable.
What makes a good request
- The consensus protocols specify three-dimensional or thin-section FLAIR with sagittal reformats, coverage that includes the whole cerebellum and brainstem, and a decision about gadolinium taken on diagnostic grounds rather than routine.
- Contrast at diagnosis serves a defined purpose — an enhancing lesion alongside a non-enhancing one establishes dissemination in time on a single study. Once the diagnosis is made, routine monitoring is generally performed without gadolinium.
- Spinal cord imaging contributes independently to dissemination in space and is where the differential with small vessel disease is often settled, particularly in older patients.
Scoring this once it is done
The classification and risk tools this question ends in.
How these studies are acquired
Contrast, phases and timing for every study on the pathways above.
Confirm locally
- MRI Brain — demyelination / multiple sclerosis: timings are typical — confirm against local protocol.
- Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
- Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.
References
- 2021 MAGNIMS-CMSC-NAIMS consensus recommendations on the use of MRI in patients with multiple sclerosis (Lancet Neurology) · Primary literature
- 2024 MAGNIMS-CMSC-NAIMS consensus recommendations on MRI for the diagnosis of multiple sclerosis (Lancet Neurology) · Primary literature
- The 2024 update to the McDonald criteria for multiple sclerosis diagnosis: a guide for radiologists (AJR) · Primary literature
- American College of Radiology Manual on MR Safety: 2024 Update and Revisions. Radiology. · ACR MR Safety
- ACR Manual on MR Safety — zoning, MR Safe / MR Conditional / MR Unsafe labelling, and screening of patients and personnel · ACR MR Safety
- Safety of MRI in patients with cardiac implantable electronic devices — conditions of use, device interrogation and monitoring · Primary literature
- ACR Manual on Contrast Media — premedication regimens (elective oral prednisone 50 mg at 13/7/1 h plus diphenhydramine 50 mg at 1 h; methylprednisolone 32 mg at 12 and 2 h; accelerated IV hydrocortisone 200 mg or methylprednisolone 40 mg every 4 h; regimens under 4–5 h lack evidence of efficacy) · ACR Contrast Manual
- Management and Prevention of Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement from the ACR and the AAAAI. J Allergy Clin Immunol Pract, 2025. · Primary literature
- Schabelman E, Witting M. The relationship of radiocontrast, iodine and seafood allergies: a medical myth exposed. J Emerg Med. · Primary literature
- CAR/CSACI Practice Guidance for Contrast Media Hypersensitivity (2025) · Other
- Weinreb JC, Rodby RA, Yee J, Wang CL, Fine D, McDonald RJ, Perazella MA, Dillman JR, Davenport MS. Use of Intravenous Gadolinium-based Contrast Media in Patients with Kidney Disease: Consensus Statements from the ACR and the National Kidney Foundation. — Group II NSF risk: 0 events in 4931 administrations at eGFR <30; upper 95% CI bounds 0.07% overall, 0.2% CKD 5D, 0.5% CKD 5 non-dialysis · ACR/NKF consensus
- Woolen SA et al. Risk of NSF in patients with stage 4 or 5 CKD receiving a group II GBCA: systematic review and meta-analysis. JAMA Intern Med. · Primary literature
- ESUR Contrast Media Guidelines v10.0 — gadolinium agents and NSF risk classification — European practice diverges: after the EMA Article 31 referral the marketing authorisations of several intravenous linear agents (gadodiamide, gadopentetate, gadoversetamide) were suspended, so the ACR "group I" discussion is largely moot in the EU/UK while remaining live in the US · ESUR
- EMA — gadolinium-containing contrast agents Article 31 referral: PRAC confirms restrictions on linear agents · Other
- AAP/AAPD Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures. Pediatrics 2019;143(6):e20191000. · Other
- Sedation and anaesthesia for imaging of the infant and neonate — a brief review (feed-and-wrap, fasting, monitoring) · Primary literature
- Image Gently — reducing the need for sedation through preparation and faster protocols in paediatric imaging · Image Gently
- Contrast Media in Pregnant and Lactating Patients — AJR Special Series on Contrast Media · Primary literature
- ACOG Committee Opinion — Guidelines for Diagnostic Imaging During Pregnancy and Lactation · Other
- ACR-SPR Practice Parameter for the Use of Intravascular Contrast Media · Other
- Behrendt FF et al. Peripheral intravenous power injection of iodinated contrast media through 22G and 20G cannulas: can high flow rates be achieved safely? A clinical feasibility study. · Primary literature
- Pressure injectors for radiologists: a review — extravasation incidence and catheter/flow-rate relationships · Primary literature
Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.