MRI Brain — demyelination / multiple sclerosis
Whole brain including the full extent of the cerebellum, brainstem and upper cervical cord on the sagittal acquisitions.
Typical, not policy
Timings, volumes and delays here are representative values drawn from published guidance. Scanner generation, injector, cardiac output and local preference all move them. Confirm against your department's own protocol before you rely on a number.
When to use it
- First clinical episode suggestive of demyelination, to establish dissemination in space and time.
- Established multiple sclerosis at a treatment-decision point, as a new reference baseline.
- Routine monitoring on disease-modifying therapy, usually without gadolinium.
- Suspected progressive multifocal leukoencephalopathy or other therapy-related complication, where contrast and diffusion both matter.
- Differentiating multiple sclerosis from small-vessel disease or other white matter disease.
Technique
- Three-dimensional FLAIR is the core sequence; consensus recommends 3D acquisitions with voxels of about 1 x 1 x 1 mm so that lesions can be counted reproducibly on reformats.
- 3D or 2D T1 before contrast, plus axial T2; diffusion for alternative diagnoses.
- Where contrast is given, the enhanced T1 should follow the injection by at least about 5-10 minutes; injecting before the 3D FLAIR is one accepted way of using that interval productively.
- Cord imaging is a separate acquisition and should be requested explicitly rather than assumed to be included.
Where it goes wrong
- Slice-thickness or angulation drift between serial studies, which manufactures apparent new lesions.
- Scanning the enhanced T1 too soon after injection and under-calling active lesions.
- Giving gadolinium at every surveillance visit when the protocol question is only new or enlarging T2 lesions.
- Assuming a brain protocol covered the cord: the cervical cord is only partially and poorly assessed on brain sagittals.
Clinical questions that reach this study
Known or suspected lung cancer — stagingSuspected acute ischaemic strokeSuspected intracranial haemorrhage (non-traumatic)Suspected subarachnoid haemorrhageFirst unprovoked seizureDrug-resistant epilepsy — pre-surgical assessmentSuspected brain metastasesSuspected primary brain tumourSuspected multiple sclerosis or first demyelinating eventSuspected meningitis or encephalitisHeadache with red flag featuresHeadache without red flags (migraine, tension-type, chronic stable)Suspected normal pressure hydrocephalusCognitive impairment or suspected dementiaHead injury in childrenSuspected inflammatory spinal cord lesion (transverse myelitis)Chronic rhinosinusitis and pre-operative sinus CTSuspected physical abuse in a child — skeletal survey
Contrast
NoneGadolinium, intravenous
Where contrast is used, a macrocyclic agent at a typical single dose of about 0.1 mmol/kg, with a minimum delay of roughly 5-10 minutes before the enhanced T1 acquisition.
- Consensus practice has moved towards restricting gadolinium: it adds most at the diagnostic study and much less at routine monitoring scans where new or enlarging lesions on FLAIR answer the question.
Acquisition
- Breathing
- Free breathing.
- Preparation
- No fasting or bowel preparation for an unenhanced brain study. Establish whether gadolinium is actually needed before booking an IV slot — most brain questions do not require it. Young children and patients unable to keep still for 20-30 minutes need a sedation or general anaesthetic pathway agreed in advance.
Safety checks this protocol carries
Derived from the contrast agent and phases above, not authored here — which is why they cannot drift apart from what the protocol actually does.
- MR safety screening for implants and foreign bodies· radiographer at scan
- Sedation or anaesthesia for a child· nurse pre scan