MRI Brain — epilepsy protocol
Whole brain, with dedicated high-resolution coverage of both temporal lobes and hippocampi.
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
- Focal epilepsy of unknown cause, where a subtle structural lesion would change management.
- Drug-resistant epilepsy under consideration for surgery.
- Normal or non-diagnostic previous brain MRI in a patient with ongoing focal seizures, where the earlier study used general parameters.
- Suspected hippocampal sclerosis, focal cortical dysplasia or a low-grade epileptogenic tumour.
Technique
- The harmonised structural epilepsy protocol is built on three acquisitions: an isotropic 3D T1 at about 1 x 1 x 1 mm, an isotropic 3D FLAIR at about 1 x 1 x 1 mm, and a high in-plane resolution 2D coronal T2 angled perpendicular to the long axis of the hippocampus.
- Susceptibility-weighted imaging is commonly added for cavernomas and calcified lesions.
- Reformatting the 3D volumes perpendicular and parallel to the hippocampal axis is part of the technique, not an optional extra.
- Higher field strength and surface-coil approaches improve dysplasia detection but are not universally available.
Where it goes wrong
- Running a general brain protocol and calling it an epilepsy study: thick axial slices angled to the anterior-posterior commissure line systematically under-detect hippocampal and cortical abnormality.
- Coronal oblique slices not truly perpendicular to the hippocampus, which introduces partial volume and fake asymmetry.
- Motion degrading the isotropic acquisitions; a repeated blurred 3D FLAIR is a failed study, not a suboptimal one.
- Adding gadolinium routinely, which does not improve detection of dysplasia or hippocampal sclerosis.
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
None
- The structural epilepsy protocol is unenhanced. Contrast is added only when a tumour, vascular malformation or inflammatory cause is suspected.
Acquisition
- Breathing
- Free breathing. Motion is the dominant limitation because acquisitions are long and high-resolution.
- 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