Video Telemetry

MRI and Epilepsy

What doctors are looking for — and why a normal scan does not rule out epilepsy

An MRI scan creates detailed pictures of the structure of the brain.

In epilepsy, doctors use MRI mainly to look for a structural abnormality that could help explain why seizures are happening.

This is different from an EEG.

An EEG records electrical activity.

An MRI shows anatomy and structure.

Neither test can answer every question on its own.

NICE recommends MRI for most children, young people and adults who have been diagnosed with epilepsy, with some exceptions for epilepsy syndromes that are not normally associated with structural brain abnormalities.

What does MRI stand for?

MRI means magnetic resonance imaging.

The scanner uses:

• a powerful magnetic field

• radio waves

• and computer processing

to produce detailed images of the brain.

Unlike a CT scan, an MRI does not use ionising X-rays.

MRI is particularly useful in epilepsy because it can show subtle differences in brain structure that may not be visible on CT.

Why is MRI used in epilepsy?

MRI can help answer several important questions:

• Is there a structural reason for the seizures?

• Is one particular brain region abnormal?

• Does the MRI finding fit the seizure symptoms and EEG?

• Could the abnormality affect treatment choice?

• Might surgery eventually be an option?

• Has something changed since an earlier scan?

NICE explains that neuroimaging can help identify the cause of epilepsy, provide information about prognosis and help plan appropriate management.

Does everyone with epilepsy need an MRI?

Not quite.

Current NICE guidance says MRI should be offered to children, young people and adults diagnosed with epilepsy unless they have idiopathic generalised epilepsy or self-limited epilepsy with centrotemporal spikes.

The scan should normally:

• take place within six weeks of the MRI referral

• and use a regionally agreed epilepsy MRI protocol.

Some recognised generalised epilepsy syndromes do not usually result from a structural abnormality visible on MRI.

Examples include syndromes such as:

• childhood absence epilepsy

• juvenile absence epilepsy

• juvenile myoclonic epilepsy

• and epilepsy with generalised tonic-clonic seizures alone.

However, imaging may still become appropriate when the diagnosis is uncertain, seizures behave unusually or treatment is unsuccessful.

What is an epilepsy-protocol MRI?

Not every brain MRI is identical.

An epilepsy MRI protocol uses particular imaging sequences and orientations designed to make abnormalities associated with epilepsy easier to detect.

This is important because some epileptogenic abnormalities can be extremely subtle.

The International League Against Epilepsy developed a minimum structural imaging protocol called HARNESS-MRI — Harmonized Neuroimaging of Epilepsy Structural Sequences.

Its core includes high-resolution structural sequences designed to show:

• overall brain anatomy

• grey and white matter

• the cortex

• hippocampi

• and subtle changes in tissue signal.

The protocol includes high-resolution 3D T1-weighted and FLAIR imaging together with high-resolution T2 imaging particularly useful for evaluating structures such as the hippocampus.

Why does the MRI protocol matter?

A very obvious brain abnormality may be visible on almost any reasonable scan.

Subtle epilepsy-related abnormalities are different.

For example, some forms of focal cortical dysplasia may involve only a small area where:

• the cortex is slightly thickened

• the boundary between grey and white matter is blurred

• or the normal organisation of brain tissue is subtly altered.

A standard brain scan that was not optimised for epilepsy may miss this.

High-quality imaging, appropriate sequences and expert interpretation can substantially improve the chance of identifying a lesion. The ILAE continues to emphasise optimised epilepsy imaging protocols and specialist image interpretation.

What are doctors looking for?

There is no single “epilepsy mark” on an MRI.

Doctors look for several different types of structural abnormality that can be associated with seizures.

These include:

• hippocampal sclerosis

• focal cortical dysplasia

• other malformations of cortical development

• previous stroke

• old brain injury

• scar tissue

• vascular abnormalities

• previous infection or inflammation

• certain tumours

• congenital abnormalities

• and other structural lesions.

Epilepsy Action identifies previous injury, stroke, haemorrhage, infection, tumours and abnormalities present from birth among the structural causes MRI may reveal.

What is hippocampal sclerosis?

The hippocampus is a structure deep within the temporal lobe.

It has important roles in memory and learning and is also commonly involved in temporal lobe epilepsy.

Hippocampal sclerosis describes characteristic damage and scarring affecting the hippocampus.

On MRI, specialists may look for features including:

• reduced hippocampal volume

• altered signal on T2 or FLAIR images

• loss of normal internal architecture

• and asymmetry between the two hippocampi.

Hippocampal sclerosis is strongly associated with some forms of mesial temporal lobe epilepsy, although an MRI finding always needs to be interpreted alongside seizure symptoms and other tests.

Does hippocampal sclerosis always mean epilepsy?

No.

An imaging finding does not diagnose epilepsy by itself.

Doctors consider:

• the person's seizure history

• EEG findings

• which side symptoms suggest

• memory and neuropsychological testing

• and other investigations.

The question is whether all the evidence points towards the same brain region.

This becomes especially important when epilepsy surgery is being considered.

What is focal cortical dysplasia?

Focal cortical dysplasia, often shortened to FCD, is an abnormality in how a small part of the cerebral cortex developed.

The cortex is the outer layer of the brain.

In FCD, brain cells and cortical organisation within a particular region developed differently from normal.

Focal cortical dysplasia is an important structural cause of focal epilepsy.

The ILAE has a specialist classification system for different forms of FCD, reflecting differences in the underlying tissue abnormality.

Why can focal cortical dysplasia be difficult to see?

Some areas of FCD are obvious.

Others are extremely subtle.

Radiologists may look for features such as:

• abnormal cortical thickness

• unusual folding

• blurring between grey and white matter

• abnormal signal

• or a characteristic abnormal band extending towards deeper brain structures.

Some abnormalities are so subtle that they are only recognised after:

• repeat MRI

• higher-quality epilepsy imaging

• specialist review

• image post-processing

• or comparison with EEG and seizure-localisation information.

This is one reason a previous report saying “MRI normal” does not always mean no structural abnormality exists.

What are malformations of cortical development?

During development before birth, billions of brain cells must:

• form

• move to the correct location

• organise themselves

• and develop normal connections.

If part of this process develops differently, a malformation of cortical development may result.

Focal cortical dysplasia is one example.

Other developmental abnormalities can also be associated with epilepsy.

Some are easily visible on MRI.

Others may require specialist epilepsy imaging to recognise.

Can a previous stroke cause epilepsy?

Yes.

A stroke damages an area of brain tissue.

The damaged tissue and the surrounding brain networks may later become capable of generating seizures.

This is one reason epilepsy can begin many months or even years after a stroke.

MRI can show evidence of previous:

• ischaemic stroke

• haemorrhage

• or other vascular injury.

NICE's evidence review found that vascular abnormalities are particularly important structural findings in people developing epilepsy later in life.

Can an old head injury be visible?

Sometimes.

A significant previous brain injury may leave:

• scar tissue

• areas of tissue loss

• evidence of previous bleeding

• or other structural changes.

These changes can sometimes be associated with post-traumatic epilepsy.

However, not every head injury produces visible MRI abnormalities, and not every abnormality seen after an injury necessarily explains someone's seizures.

Can previous infection cause epilepsy?

Yes.

Brain infections such as:

• encephalitis

• meningitis

• and certain other infections

can sometimes damage brain tissue.

That damage may later contribute to epilepsy.

MRI may show:

• scarring

• tissue loss

• calcification on other imaging

• or abnormalities in particular brain regions.

Epilepsy Action includes previous meningitis and encephalitis among structural causes an MRI may help identify.

Can epilepsy be caused by a brain tumour?

Some brain tumours can cause seizures.

Importantly:

“Tumour” does not automatically mean aggressive cancer.

Several slow-growing or low-grade brain tumours are particularly associated with seizures.

In some people, seizures may be the first symptom that leads to the tumour being discovered.

MRI helps doctors assess:

• where the lesion is

• its size

• its appearance

• surrounding brain tissue

• and whether further investigation is needed.

Treatment depends entirely on the type and location of the lesion.

What are vascular malformations?

Blood vessels in the brain can sometimes develop abnormally.

Examples include:

• cavernous malformations

• arteriovenous malformations

• and other vascular abnormalities.

Some can irritate or damage nearby brain tissue and contribute to seizures.

MRI can detect many of these abnormalities, although particular sequences or other forms of vascular imaging may sometimes be needed.

What does “lesion” mean?

The word lesion simply means an area of tissue that appears abnormal.

It does not tell you the cause.

A lesion might represent:

• scar tissue

• developmental abnormality

• tumour

• vascular abnormality

• previous injury

• inflammation

• or another structural change.

So if a report says “lesion”, the next question should be:

“What type of lesion?”

rather than assuming it means cancer or something immediately dangerous.

What is lesional epilepsy?

The phrase lesional epilepsy is sometimes used when imaging identifies a structural lesion believed to be responsible for the person's seizures.

Doctors may look for agreement between:

• MRI location

• seizure symptoms

• EEG

• video telemetry

• neuropsychological testing

• and other investigations.

The stronger the agreement between these different sources of information, the greater the confidence that the lesion is genuinely involved in the seizures.

What is MRI-negative epilepsy?

Someone may have convincing epilepsy but no structural abnormality visible on MRI.

This is sometimes described as MRI-negative epilepsy.

It does not mean:

• the seizures are imaginary

• the person does not have epilepsy

• the EEG must be normal

• or treatment cannot work.

Epilepsy Action specifically notes that many people with epilepsy have normal MRI scans and that the abnormality may simply be too small or subtle for the scan to detect.

Why can epilepsy exist when MRI is normal?

Epilepsy is fundamentally a disorder of abnormal electrical activity and brain networks.

A structural lesion visible on MRI is one possible cause, not a requirement.

Some epilepsies arise because of:

• genetic mechanisms

• microscopic abnormalities below MRI resolution

• changes in ion channels or receptors

• subtle network dysfunction

• metabolic mechanisms

• immune causes

• or structural abnormalities too small or difficult to see.

Therefore:

Normal MRI ≠ no epilepsy.

Just as:

Normal EEG ≠ no epilepsy.

Can an MRI itself diagnose epilepsy?

Not usually.

NICE states that neuroimaging should be used to investigate possible structural causes of epilepsy rather than as a standalone diagnostic test.

A structural abnormality may strongly support the diagnosis when it fits the seizure history.

But doctors still need to decide whether the person's events are genuinely epileptic.

Some people have incidental MRI abnormalities that have nothing to do with their symptoms.

What is an incidental finding?

An incidental finding is something discovered on a scan that was not the reason the scan was performed.

For example, MRI might identify:

• a small benign cyst

• a developmental variation

• minor vascular changes

• or another abnormality unrelated to the seizures.

The existence of an MRI abnormality does not automatically mean:

“This is where the seizures come from.”

The finding must make neurological sense when compared with the rest of the evidence.

How do MRI and EEG work together?

EEG and MRI answer different questions.

EEG asks:

What is the electrical activity doing?

It can provide evidence about:

• epileptiform activity

• focal or generalised patterns

• possible seizure onset

• and epilepsy syndrome.

MRI asks:

What does the brain structure look like?

It can identify:

• scars

• developmental abnormalities

• hippocampal sclerosis

• tumours

• vascular lesions

• and other structural causes.

When EEG and MRI point to the same region, the combined evidence can be particularly useful.

Related Information Hub page:
EEG: What It Can — and Cannot — Tell You About Epilepsy

Can the EEG be abnormal on one side but MRI be normal?

Yes.

This happens frequently.

The EEG may suggest seizures arise predominantly from one brain region even though the MRI looks structurally normal.

Possible explanations include:

• microscopic abnormalities

• very subtle cortical dysplasia

• electrical network dysfunction without a visible lesion

• or an abnormality that current imaging cannot resolve.

Further investigation may be considered if seizures remain uncontrolled.

Can MRI show an abnormality on one side but EEG appears different?

Yes.

This is sometimes called discordant information when different tests do not clearly agree.

There can be several explanations.

For example:

• the MRI lesion may be incidental

• seizures may spread rapidly

• scalp EEG may not accurately show a deep seizure onset

• there may be more than one abnormal brain region

• or additional investigations may be needed.

Discordant findings are particularly important during epilepsy-surgery assessment and are usually reviewed by a specialist multidisciplinary team.

Why is the hippocampus scanned so carefully?

The hippocampus lies deep in the temporal lobe and is a common site involved in focal epilepsy.

Very small differences between the left and right hippocampus can matter.

Epilepsy MRI protocols therefore use imaging that provides detailed views of the hippocampal structures.

The ILAE HARNESS protocol specifically includes high-resolution imaging designed to improve detection of hippocampal and cortical abnormalities.

Does the MRI tell doctors which symptoms someone should have?

It can help generate a hypothesis.

Different brain regions are associated with different functions.

For example:

Temporal lobe

Seizures may involve:

• altered awareness

• memory phenomena

• unusual smells or tastes

• fear

• automatisms

• or other experiential symptoms.

Frontal lobe

Seizures may involve:

• unusual movements

• tonic posturing

• rapid motor activity

• brief events

• or seizures arising predominantly from sleep.

Occipital lobe

Seizures can involve visual symptoms.

Parietal lobe

Seizures may involve unusual sensory or spatial experiences.

But seizure symptoms alone do not perfectly identify the location.

The seizure can spread rapidly to other networks.

MRI is therefore interpreted alongside seizure semiology — the detailed description of what happens during a seizure.

Can MRI detect every cause of epilepsy?

No.

MRI is extremely powerful, but it has limits.

It may not detect:

• microscopic abnormalities

• purely genetic epilepsy

• subtle network changes

• tiny cortical abnormalities

• some immune or metabolic causes

• or abnormalities that require a different imaging technique.

This is why MRI is one part of a broader epilepsy investigation.

When might an MRI be repeated?

NICE recommends considering another MRI when:

• the original scan was suboptimal

• new features have developed

• an epilepsy normally not associated with structural abnormalities has failed to respond to first-line treatment

• or epilepsy surgery is being considered.

Repeat imaging does not necessarily mean doctors think something dangerous has developed.

Sometimes the purpose is simply to obtain better-quality or more specialised images.

What does “suboptimal MRI” mean?

A scan may be considered suboptimal if:

• movement blurred the images

• the scanner or protocol did not provide sufficient detail

• epilepsy-specific sequences were not performed

• important areas were not adequately visualised

• or the images were obtained many years earlier using older technology.

A technically normal scan is only as useful as the quality of the images available.

Why might an old MRI be reviewed again instead of immediately repeated?

Sometimes the original images contain useful information that simply was not recognised at the time.

NICE recommends considering additional review by a specialist neuroradiologist in a tertiary centre when:

• seizures continue despite treatment

• and the diagnosis remains unclear.

An epilepsy specialist neuroradiologist may examine the images knowing:

• the suspected seizure onset

• EEG findings

• seizure behaviour

• and the precise clinical question.

That targeted review can sometimes reveal abnormalities that were difficult to appreciate previously.

Who should report an epilepsy MRI?

NICE recommends that MRI scans in people with epilepsy are reported by a radiologist with appropriate neuroradiology expertise.

This matters because epilepsy imaging can involve abnormalities much subtler than the major conditions often sought on ordinary emergency scans.

Experience matters.

Does a 3-tesla MRI always find more than a 1.5-tesla MRI?

MRI scanners have different magnetic field strengths.

Common clinical scanners include:

• 1.5 tesla

• and 3 tesla.

A 3T scanner can provide greater signal and potentially higher-resolution images.

However, field strength is only one factor.

Diagnostic quality also depends on:

• imaging sequences

• movement

• coil quality

• technical expertise

• epilepsy protocol

• and specialist interpretation.

A poorly performed 3T scan is not automatically superior to a well-performed epilepsy-protocol examination.

The ILAE's HARNESS recommendations focus heavily on achieving appropriate high-resolution structural sequences rather than treating scanner strength alone as the answer.

What happens during an MRI?

The person lies on a movable bed.

Their head is positioned inside a specialised receiver coil, and the bed moves into the scanner.

During the examination, the scanner makes loud:

• knocking

• tapping

• buzzing

• and mechanical sounds.

Ear protection is provided.

The person needs to remain as still as possible while each sequence is collected.

Movement can blur the images and make subtle abnormalities harder to identify.

Does MRI hurt?

No.

The magnetic field and radio waves are not painful.

The main difficulties some people experience are:

• remaining still

• noise

• enclosed space

• anxiety

• discomfort from lying in one position

• or fear of the scanner.

Anyone worried about claustrophobia should tell the radiology department before the appointment.

There may be ways to make the examination easier.

How long does an epilepsy MRI take?

The precise length varies according to:

• the scanner

• protocol

• whether extra sequences are needed

• and whether contrast is used.

An epilepsy MRI is often more detailed than a very short emergency brain scan.

The appointment may therefore take longer because several different image sequences are needed.

The radiology department can give the most accurate estimate for the particular examination.

What if someone moves during the MRI?

Movement makes the images blurry.

Large abnormalities may still be visible, but subtle findings such as focal cortical dysplasia can become much harder to detect.

The radiographer may need to repeat part of the scan.

For children or people who cannot remain still, sedation or general anaesthesia is sometimes considered.

NICE says the risks and benefits should be discussed particularly when sedation or general anaesthesia is required.

Does MRI cause seizures?

MRI itself does not normally provoke epileptic seizures.

It does not stimulate the brain in the way flashing lights during EEG may be used as an activation procedure.

However, someone with active epilepsy could coincidentally have a seizure during any appointment.

If a person has particular concerns, they should tell the radiology team.

Can medication be taken before an MRI?

Usually, yes.

Antiseizure medication should normally be taken as prescribed unless the medical team has specifically given different instructions.

There is generally no diagnostic benefit in deliberately missing epilepsy medication for a structural MRI.

Missing medication could unnecessarily increase seizure risk.

Is contrast always needed?

No.

Many epilepsy MRI examinations can be performed without an injected contrast agent.

Sometimes a contrast agent containing gadolinium may be used when doctors need additional information about a suspected:

• tumour

• inflammation

• infection

• vascular problem

• or another particular abnormality.

The radiology team decides whether contrast is necessary.

Epilepsy Action notes that contrast is sometimes injected to make particular tissues or changes clearer.

What is gadolinium?

Gadolinium-based contrast agents alter the appearance of certain tissues on MRI and can make some abnormalities easier to characterise.

Before contrast is given, staff may ask about:

• kidney problems

• previous contrast reactions

• allergies

• pregnancy

• and other health conditions.

Serious reactions are uncommon, but contrast should only be used when clinically appropriate.

Is MRI safe during pregnancy?

MRI does not use ionising radiation.

MRI may be performed during pregnancy when there is a clear clinical need.

Whether contrast is necessary requires additional consideration.

Someone who is pregnant or thinks they may be pregnant should tell the radiology department before the scan so the examination can be appropriately planned.

What about metal implants?

Because MRI uses a powerful magnetic field, some metal or electronic devices require special assessment.

Before entering the MRI area, people are screened for items such as:

• pacemakers

• implanted stimulators

• surgical clips

• cochlear implants

• metal fragments

• pumps

• and other implanted devices.

Many modern medical devices are MRI conditional, meaning scanning may be possible under particular conditions.

Never assume an implant is safe or unsafe without checking its exact details.

What if someone cannot have MRI?

NICE recommends considering CT when MRI is contraindicated.

For example, MRI might not be possible because of:

• a non-compatible implanted device

• certain metal fragments

• or occasionally severe inability to tolerate the scanner.

CT is faster and can be excellent for some conditions, but it generally provides less detailed information about many subtle epilepsy-related structural abnormalities.

What is the difference between MRI and CT?

MRI

Uses magnetic fields and radio waves.

Advantages include:

• excellent soft-tissue detail

• detailed views of cortical structures

• good hippocampal assessment

• no ionising radiation.

CT

Uses X-rays.

Advantages include:

• very fast imaging

• wide availability

• excellent detection of acute bleeding

• good detection of skull injury

• and usefulness in emergencies.

For long-term structural investigation of epilepsy, MRI is generally preferred.

Why might CT be used after a first seizure?

In an emergency, doctors may need to answer questions such as:

• Is there acute bleeding?

• Has there been major head trauma?

• Is there a large mass?

• Is there another urgent structural cause?

CT can answer these questions quickly.

MRI can then provide more detailed epilepsy-specific structural imaging later if appropriate.

Does someone with established epilepsy need a CT after every seizure?

Usually not.

NICE specifically states that people with established epilepsy who attend an emergency department after a typical seizure should not routinely have CT unless there are other concerns.

Other concerns might include situations such as:

• significant head injury

• new neurological findings

• a very different event from usual

• or another suspected acute problem.

MRI and epilepsy surgery

MRI becomes especially important when seizures continue despite appropriate medicines.

Some people have a well-defined structural abnormality that appears responsible for their seizures.

If that abnormality can potentially be treated surgically without unacceptable harm to important functions, epilepsy surgery may be considered.

This requires much more than simply seeing a lesion.

Specialists need to understand:

• where seizures actually begin

• where important functions are located

• how the seizure network spreads

• and whether removing or disconnecting the epileptogenic tissue is feasible.

What happens if MRI shows a lesion that might be operable?

The person may be referred to a specialist epilepsy-surgery service.

Further investigations can include:

• prolonged video EEG

• neuropsychological testing

• specialised MRI review

• functional MRI

• PET

• SPECT

• MEG

• EEG source imaging

• and, in selected cases, intracranial EEG or SEEG.

The exact combination depends on the individual.

MRI is one piece of that larger puzzle.

What is functional MRI?

Functional MRI, or fMRI, is different from ordinary structural MRI.

Instead of primarily looking for structural abnormalities, fMRI measures changes in blood oxygenation associated with brain activity.

In epilepsy-surgery assessment, it can help specialists understand where important functions such as:

• language

• movement

• and sometimes memory-related networks

are located.

The ILAE includes functional and multimodal imaging among the advanced methods used in epilepsy assessment.

What is MRI post-processing?

Sometimes computer methods are used to analyse MRI data in ways that may make subtle abnormalities easier to detect.

These methods can examine features such as:

• cortical thickness

• tissue intensity

• surface shape

• grey-white matter boundaries

• and regional brain volumes.

The ILAE recommends computer-aided image post-processing as a useful addition in appropriate epilepsy imaging, particularly when subtle lesions are suspected.

This does not replace expert radiology.

It provides another tool for identifying areas that deserve closer inspection.

Can artificial intelligence find lesions that humans miss?

Research increasingly uses machine-learning and AI techniques to help detect subtle epilepsy-related abnormalities, particularly focal cortical dysplasia.

These methods are promising, but they do not replace the neurologist or neuroradiologist.

The ILAE's current neuroimaging educational programme includes both automated post-processing and AI techniques as developing areas in epilepsy imaging.

An algorithm can highlight suspicious areas.

Clinical experts still need to decide whether those findings make neurological sense.

Does a normal MRI mean surgery is impossible?

No.

Some people with MRI-negative drug-resistant focal epilepsy can still be evaluated for surgery.

Specialist centres may use:

• detailed video EEG

• PET

• SPECT

• MEG

• high-resolution repeat MRI

• image post-processing

• neuropsychology

• and intracranial EEG

to identify the seizure-onset region.

Epilepsy Action notes that people whose seizures remain uncontrolled should still be considered for specialist assessment even when MRI is normal.

Why might epilepsy suddenly change years after an old MRI?

A new pattern deserves review.

Examples include:

• a new seizure type

• unexpected increase in frequency

• new neurological symptoms

• cognitive deterioration

• or seizures that stop responding as expected.

NICE identifies new epilepsy features as one reason to consider additional MRI.

A repeat scan does not automatically mean clinicians suspect a tumour.

It means the clinical picture has changed enough to justify reassessing the brain structure.

Can MRI show which side memory problems come from?

MRI can reveal structural abnormalities in brain regions important for memory, particularly the hippocampi.

But memory is a complex brain function involving multiple networks.

MRI alone cannot determine exactly:

• which memories are affected

• how severe the impairment is

• or whether medication, seizures, mood, sleep or another factor is contributing.

Neuropsychological testing is often used when detailed memory and cognitive assessment is needed.

That will have its own Information Hub page later.

What does “mesial temporal” mean?

Temporal refers to the temporal lobe.

Mesial means towards the inner or middle portion.

The mesial temporal structures include:

• hippocampus

• amygdala

• and nearby structures.

Mesial temporal lobe epilepsy refers to focal epilepsy arising from networks in this region.

Hippocampal sclerosis is one important structural abnormality associated with this form of epilepsy.

What if the report says “no structural cause for seizures identified”?

This generally means the radiologist did not see a structural abnormality on that scan that clearly explains the seizures.

It does not mean:

• the seizures did not happen

• the person does not have epilepsy

• nothing is wrong

• or further investigation is pointless.

Many people with genuine epilepsy have normal MRI results.

The neurologist will interpret the MRI alongside the rest of the evidence.

What if the report mentions “non-specific” changes?

MRI commonly reveals small abnormalities whose significance is uncertain or unrelated to epilepsy.

The term non-specific generally means the finding is not characteristic of one particular diagnosis.

The neurologist needs to consider:

• age

• medical history

• vascular risk factors

• symptoms

• seizure type

• and the location of the finding.

Do not assume every line in an MRI report is the cause of epilepsy.

What questions should someone ask about their MRI?

Useful questions include:

• Was this performed using an epilepsy MRI protocol?

• Was the scan completely normal?

• Was any structural abnormality found?

• Could that abnormality explain my seizures?

• Which brain region is involved?

• Does it match my EEG?

• Does it match what happens during my seizures?

• Was either hippocampus abnormal?

• Was focal cortical dysplasia considered?

• Does the scan need specialist neuroradiology review?

• Was the image quality good enough?

• Is another MRI needed?

• Would a higher-resolution scan provide more information?

• Does this result affect my treatment?

• Does it affect whether I should be assessed for epilepsy surgery?

The most important message

MRI does not look for epilepsy itself.

It looks for structural abnormalities that might help explain epilepsy.

Those abnormalities can include:

• hippocampal sclerosis

• focal cortical dysplasia

• developmental abnormalities

• old injuries

• stroke

• infection-related damage

• vascular lesions

• tumours

• and other structural changes.

A specialised epilepsy MRI protocol matters because some epileptogenic lesions are extremely subtle.

A normal MRI does not rule out epilepsy.

And an abnormal MRI does not automatically prove that the abnormality causes someone's seizures.

The most useful interpretation comes from asking whether the MRI agrees with:

• the person's seizure symptoms

• EEG

• video telemetry

• neurological examination

• and other investigations.

If epilepsy remains uncontrolled despite treatment, a previously normal MRI should not prevent referral for specialist assessment.

Sometimes the answer is not that there is “nothing there”.

It is that more detailed imaging, specialist review or a different way of looking at the seizure network is needed.

Sources and further reading

NICE — Epilepsies in children, young people and adults (NG217): Diagnosis and assessment.
Current NICE guidance recommends epilepsy-protocol MRI for most people diagnosed with epilepsy, usually within six weeks of referral. It also sets out when specialist review or repeat MRI should be considered.

NICE — Rationale and impact: Neuroimaging.
Explains why MRI is the preferred structural investigation, the importance of specialist neuroradiology and circumstances in which repeat imaging may be appropriate.

International League Against Epilepsy Neuroimaging Task Force — Recommendations for structural MRI in epilepsy.
The ILAE consensus report introduced the HARNESS-MRI protocol and emphasised high-resolution epilepsy-specific imaging and specialist image analysis.

International League Against Epilepsy — Neuroimaging education and Imaging Task Force.
Current ILAE work continues to focus on optimised MRI protocols, MRI-negative epilepsy, post-processing, focal cortical dysplasia and advanced imaging techniques.

Epilepsy Action — MRI scans and epilepsy.
Current UK patient information covering structural causes, normal MRI results, repeat imaging, epilepsy surgery and what happens during an MRI. Last modified November 2025.

Information reviewed: September 2026.

This page provides general educational information. MRI results should be interpreted by appropriately trained healthcare professionals alongside the person's seizure history, EEG and other investigations.