MEG scans

The brain works by a series of nerve impulses, which cause electrical signals within the brain. These signals (also called brainwaves) can be recorded through the scalp using an electroencephalogram (EEG). The electrical signals also produce weak magnetic fields, which can be measured through the skull and scalp using a magnetoencephalogram (MEG) scan.

A MEG scan is part of the detailed assessment needed before epilepsy surgery is planned. Magnetic fields are measured and allow a detailed ‘map’ of the brain and any seizure focus to be built up, which can be helpful when planning epilepsy surgery.

Unfortunately, we do not have the facility to offer MEG scans at Great Ormond Street Hospital (GOSH), but we work closely with the Hôpital Erasme in Brussels to provide the data we need. There are MEG scanning units in the UK but they are only suitable for adults or older children who do not need sedation. Your child’s doctors will only suggest a MEG scan in Brussels if they believe that more detailed results are needed to assess your child’s epilepsy. Usually this decision follows other testing.

Once the team at GOSH has decided that the MEG scan is necessary, we agree funding to pay for the scan, your child’s stay in hospital, sedation if required, hotel accommodation for one night and flights/train fare for your child and one accompanying parent. If other family members want to travel too, they will need to fund this privately.

There are several things that need to be organised before travelling to Brussels for your child’s MEG scan.

Your child and accompanying parent with parental responsibility will require a passport to travel. If it is close to expiry, has expired or you do not have a passport, you can get a form to complete from the Post Office. You will need to send this back with two passport photographs to get a new one. There are various payment options available to you depending on how quickly you need a new passport. Information about the passport application process is available from the HM Passport Office.

If you are not a UK citizen, we can assist you with letters to support your need to travel, if required, to obtain appropriate visas both for the UK and Brussels through your embassy.

You need one of these to travel within Europe as it guarantees that you and your child will receive treatment in hospitals abroad without having to pay. You will need to fill in an online form to apply for this card.

Travel insurance is important for you and your child’s belongings and health. Make sure that if you require travel insurance that this also covers your child’s additional medical conditions.

Belgium uses the Euro (€) and you will require some currency to pay for things such as travel, food and drink. Your debit and credit cards will work in most cash machines in Brussels but it is wise to take some currency with you when you travel for taxi fares and other small expenses.

As you will only be staying in Brussels a short time, please do not pack too much, as space will be limited. You will need clothes and wash things for yourself and your child, things to occupy both of you, such as books and games, and perhaps a favourite toy.

Belgium operates a two-pin continental plug system which is different to the UK so if you are taking anything electrical, such as a mobile phone charger, you will also need to take a travel plug adapter.

The hospital’s name is 'Hôpital Erasme' in French or 'Erasme Hospital' in English. The address is 808 Lennik Street 1070 Brussels. You and your child will travel by Eurostar and will arrive at Brussels south station ('Gare du midi' in French). This will be organised and paid for by GOSH.

Sometimes flights will be arranged instead of Eurostar if this is deemed a more suitable method of transport. Depending on the airline used, you will arrive at either Brussels Airport or Brussels South Airport.

• If flying into Brussels Airport, you will need to take a train to Gare Centrale and then take Metro line 5 up to Erasme (see metro section for more details).

• If travelling via Brussels South Airport (Ryanair), there is a shuttle coach that connects this airport with Gare du midi in Brussels.

It is sensible to write the name of the hotel/hospital on a piece of paper to show the taxi driver, as they may not speak French as their first language. The Hotel Erasme/Hospital Erasme are pronounced as 'ER-AS-Mmm'.

To get to Erasme hospital via the metro, you have to take either line 2 or 6 from Gare du Midi to Gare de l’Ouest, where you change to line 5 to Erasme, which is the terminus of the line. You have to buy tickets at a machine before you travel and then stamp them at another machine before you get on the train. The machine takes coins and cards but not notes. Each ticket costs €2.

As you come out of Erasme station, you need to go down the stairs from the platform, turn right at the bottom and go up the stairs at the end. At the top of the stairs you turn around and walk about 300 yards to the hotel on the right.

Accommodation will be arranged by staff at GOSH. You and your child will be booked into the Hotel Erasme, which is located next to the hospital at 790 Lennik Street 1070 Brussels. There is a brasserie in the hotel which serves food, but please note that the hotel and hospital are in the suburbs of Brussels and not the city centre so alternative eating facilities will be limited. The hotel has an online map showing where the hotel is located beside the hospital.

You will need to register at the desks located on the left hand side when you enter the main entrance of the hospital to obtain a hospital ID number as well as show the proof of payment. Proof of payment will be given to you by GOSH.

Ask the receptionist to contact Dr Xavier De Tiège (Associate Professor, Unité de Magnétoencéphalographie). Many people in the hospital may not speak good English although Dr Xavier speaks fluent English.

You will need to arrive at the paediatric ward (level 2 of the hospital, the door of the ward is easily recognisable because it is the only one with some paintings on the door) at 8am. When you get to the paediatric ward, your child will be seen by the paediatricians and they will decide to start the sedation.

Sedation involves medications by mouth, by intramuscular injection and by rectum. Sedation works well over 90 per cent of the time. If it does not work, it may not be possible for your child to have the MEG scan as planned. The MEG will be done around 10am when your child is fully sedated.

Note: If your child has a cold or a fever the day before, please contact GOSH to determine if they are fit to come to Brussels!

You need to be at the MEG unit at 10am.

For sedated patients: no food intake from six hours before the sedation. Patients can take their medication with some sips of water. Sedation will be given via an intramuscular injection or given rectally.

For unsedated patients: no specific preparation is required.

For both groups of patients: Patients will be changed into hospital gown/scrubs for the procedure. No metallic objects such as removable braces, jewel, piercings, glasses, and so on are allowed. Neither are make-up or under-wired bras.

Fixed braces may be of concern, please inform us when we arrange your scan if your child has braces in place as this can make the scan data unreadable. If patients have a VNS device, VP shunt, or any other implanted device, we need to know in advance because this can affect MEG signal. Your child can still have the MEG scan but it may make the data more difficult to analyse.

Preparation takes 30 to 45 minutes. The MEG team put four electrodes on the patient’s head (head position indicator coils) that will help to localize the patient’s head inside the MEG helmet. Then there are tests to map where these four electrodes are on the patient’s head using an electromagnetic tracker. Finally, we use electro-oculogram (to record eye movements) and ECG electrodes. None of this is painful. It is like EEGs that your child has had before.

It will take about one hour to do the scan. The seat will be tilted back so that your child will be in a lying down position. They can close their eyes and rest (most children fall asleep even if they have not had sedation). For unsedated patients, if needed, a parent can stay with their child inside the special MEG magnetic shielded room; parents are also provided a hospital gown/scrubs.

After an hour or so, your child will be taken back to the ward. Throughout the day, your child will be monitored closely to check that they are recovering if they have had sedation. He/she will be able to start eating and drinking, usually water to start. Your child will be discharged once they are eating well without vomiting (being sick) and has passed urine. You are then free to return to the hotel for the night before travelling back to the UK the following day, or to travel home if that is the plan.

This is basically a reverse of the journey to Brussels.

The results of the MEG scan are usually sent to GOSH. Your doctors will then call you to arrange a clinic appointment to discuss the results and any future plans.