Magnetic resonance imaging of the brain Procedure: Mr Bodypart: Head Patient Group: Female Male Child

Summary Synonyms: MR, MRT, MRI brain scan, cranial MRI Magnetic resonance imaging of the brain is a special in-depth procedure used where diseases, damage to or malformation of the brain are suspected. By using a powerful magnetic field, electromagnetic waves and special computers, it is possible to visualise the blood vessels and parts of the brain as cross-sectional images or as three-dimensional reconstructions without using potentially harmful X-rays. The radiologist can thus obtain information about the inside of the body and associate any changes with a particular disease. This makes it possible to obtain a precise diagnosis and plan the corresponding treatment. Magnetic resonance imaging of the brain is currently the most sensitive method for assessing the brain. 1

Technique What it is An MRI of the brain is an ultra-modern procedure for examining the body using a magnetic field, electromagnetic waves and special computers. Cross-sectional images or three-dimensional reconstructions of the brain are created and assessed by the radiologist on a monitor. 1

How it works

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A magnetic resonance scanner (MRI scanner) is a piece of equipment which generates a powerful and very regular magnetic field using a cylindrical magnet. This magnetic field also affects the human body, which consists of many tiny molecules and atoms that are aligned in the same direction in the magnetic field, just like miniature needles on a compass. These can be given a slight nudge by means of an electromagnetic pulse (similar to a radio signal), causing them to oscillate from side to side for a few milliseconds in the magnetic field, before realigning themselves in parallel. The duration and extent of this movement depend on the type of molecules and atoms, as well as their environment and mobility options, i.e. on the type of tissue in question. For example, atoms in a liquid move much more freely than the atoms in a bone. These small differences can be measured by the MRI scanner and converted into an image of the body by a special computer. However, as an image can only be created from several thousand individual measurements, this process may take slightly longer. In the case of certain diagnostic tasks, contrast agents are also injected during the procedure to make the vessels, or the flow of blood through tissues, more visible, typically using a synthetic intravenous cannula inserted in the elbow. MRI of the brain © Wikipedia 1

Purpose Brain tissue can be examined very thoroughly by means of an MRI brain scan. Data from the procedure can also be used to plan treatment by surgeons or operating radiologists, e.g. surgical removal of a tumour or targeted radiotherapy. Ambiguous results from a preliminary examination (e.g. CT) can often be assessed definitively. The aim is to detect any changes, to distinguish between malignant and non-malignant changes and to classify these accurately where possible so that a suitable treatment programme can be initiated if required. 1

Target Patient Group An MRI brain scan is performed for various diagnostic tasks: •# Brain tumours • Strokes - Brain injuries # • Chronic diseases of the central nervous system, e.g. multiple sclerosis # • Investigation of the causes of headaches # • Congenital anomalies of the brain (malformation) # • Vascular anomalies (e.g. aneurysms) # • Eye and inner ear problems # 1

Procedure Persons You will be looked after by an experienced team consisting of a medical radiology technician (MRI technician) and a radiologist. You will be monitored constantly via a screen in the switch room and the person carrying out the procedure will be able to see and hear you at all times. You will also be given a ball to hold in your hand, which triggers an alarm signal as soon as it is pressed. Before the procedure and depending on the diagnostic task in question, the radiologist will insert an intravenous cannula in your forearm, through which the contrast agent, and any necessary medication, can be administered. Once the images have been created, the radiologist will examine and assess them and then draw up a written report. This is given to you or sent on to the doctor who referred you. Please note that it may take several days for the report to be prepared. 1 Generated from XML by patientinfo.myesr.org. Copyright © European Society of Radiology (ESR) http://www.myesr.org

Preparation 1. You can usually eat a light meal before the procedure, but please observe the instructions issued by your MRI clinic in this respect. You can usually drink as much water or juice as you like. 2. You should take your usual daily medication with some liquid in the morning. 3. If you are a diabetic, please ask your doctor how you should take your medication on the day of your procedure. If you think that your blood sugar levels are low, please inform the MRI technician immediately. 4. Before the procedure, please tell the radiologist about all medication you are taking. It is best to prepare a list of all current medication. 5. If you have implants of any kind (e.g. pacemaker, cochlear implants, artificial hips, artificial heart valves, etc.), please inform the radiologist and staff before you are taken to the scanner. This is very important as the implant may overheat, get damaged or its function may be impaired as a result of the powerful magnetic field. Modern implants are often suitable for use with MRI scanners - but this must always be checked before the start of the procedure. If you have an implant certificate, please don’t forget to bring this with you for your procedure. 6. Inform the radiologist of any existing illnesses, operations (especially recent operations) and allergies or drug intolerances. 7. Please bring up-to-date lab results with you (no more than 7 days old). 8. Please tell the staff if you are claustrophobic. 9. Please make sure you tell the staff if you are pregnant. MRI has been used on pregnant women for many years, but careful consideration should be given to its use in such cases. 10. Jewellery or similar accessories should be left at home if possible or removed before the procedure, as these can cause damage and disrupt the image quality. Please note that magnetic cards - such as credit cards – can also be damaged by the magnetic field. 1

Precautions Please also inform the doctor without fail if one of the following applies: 1. Pregnancy: This procedure can be performed if you are pregnant, unlike CT and X-ray procedures, as it does not use ionising radiation. However, contrast agents may only be used in an emergency. 2. Allergies to MRI contrast agents (very rare): If you have ever had an allergic reaction to MRI contrast agents, there is a high risk associated with administering these substances again. However, if the allergic reaction was only minor, it is possible to minimise the risk of a further allergic reaction by administering an appropriate drug. Please contact the doctor who referred you before the procedure. 3. Kidney disease: If you suffer from renal impairment, you should only be given the contrast agent if your lab results permit. Please discuss this beforehand with the doctor who referred you. 4. Pacemakers / defibrillators: If you have a pacemaker or a defibrillator fitted, it will not be possible to perform an MRI scan. Life-threatening side effects could arise, as the control settings of these devices are affected by the magnetic field. 5. Metal implants / foreign objects: As a general rule, patients with metal implants or foreign objects should not have an MRI scan, as the metal can move in the magnetic field and may also become quite hot. However, modern implants such as knee or hip prostheses are usually acceptable for use with MRI scanners as they are made from titanium. The length of the metal and the strength of the equipment’s magnetic field must also be taken into account. The radiologist will decide whether or not the procedure can go ahead based on corresponding guidelines. If you have old X-rays of these implants or foreign objects, please bring them with you for your procedure. 6. Tattoos: Dyes containing metal substances are occasionally used in tattoos and these can heat up in the powerful magnetic field, causing burns to the skin. 1

Duration The entire procedure, including preparation, lasts approximately 30 to 45 minutes. The procedure may take longer as a result of additional MRI sequences in the case of particular diagnostic tasks. As in any medical facility, the start of your procedure may be delayed if emergency patients have to take precedence. Please always allow enough time. 1

Process Before the start of the procedure, you will be issued with an information sheet describing the relevant procedure again and asking you questions about any metal implants or foreign objects which you may have, whether you are pregnant, any preexisting conditions, current symptoms and allergies / intolerances. The procedure is performed with your upper body undressed. Generated from XML by patientinfo.myesr.org. Copyright © European Society of Radiology (ESR) http://www.myesr.org

Note that all foreign objects (such as necklaces, earrings, bras, etc.) must be removed before the procedure to guarantee optimum image assessment. Otherwise it will be impossible to carry out the procedure and assess the images. You will be asked to lie down on the examination table. Your head will be placed in a special frame. This frame contains special coils, which not only emit the radio pulses described above, but are also able to measure the tissue’s response behaviour. As the machine makes loud switching noises during the procedure, you will usually be given sound-insulating headphones or earplugs so that you don’t hear any noise during the procedure. Before the examination table is moved into the cylinder, you will also be given a ball to hold, which you can press to trigger the alarm in case of an emergency. The MRI scanner cylinder is approximately one meter long with a diameter of around 70 cm. This cylinder is brightly and pleasantly lit and open on the opposite side. You can talk to the operators via a microphone and they can also see you via a video camera. Depending on the diagnostic task in question, contrast agents will be administered during the procedure; this makes it much easier to see the vessels and blood flow in the tissues. This enables the radiologist to detect the smallest changes and growths and to specify these in greater detail. This means that an accurate diagnosis can often be made without the need for an operation or biopsy (where a tissue sample is removed). 1

After procedure You will usually be able to go straight home after the procedure. Please tell the staff immediately if you feel dizzy or sick. They will advise you to remain still until the symptoms improve, or for at least 30 minutes. In certain cases you may also be given medication to deal with the nausea. If you have come by car, please check with the medical staff after the procedure whether you have been given any medication which might prevent you driving your car home. 1

Consideration Risks MRI is a very low-risk procedure. Intolerance reactions to the contrast agent may occur, but only rarely. You may develop a rash and/or itching in such cases. The symptoms are usually only short-lived and disappear of their own accord. If necessary, medication may also be administered in the form of so-called antihistamines or cortisone. Metal foreign objects or prostheses may heat up in rare cases. If you feel an unusual hot sensation or pain during the procedure, report this immediately via the microphone or press the ball in your hand. On extremely rare occasions, severe allergic reactions (anaphylactic shock) may occur, accompanied by breathing and circulation problems and/or loss of consciousness. This can be a life-threatening reaction, depending on its severity, and requires immediate medical treatment. If you suffer from chronic renal impairment and are a dialysis patient, serious side effects may develop after administering certain MRI contrast agents, especially on the skin (see renal impairment info). 1

Alternatives MRI is usually the last imaging method used to investigate ambiguous changes which have been picked up in preliminary tests such as CT, angiography or radiography, but which could not be pinned down in any further detail. For this reason, conservative alternative procedures have often already been exhausted. 1

FAQ How long does a procedure last? In most cases the procedure will be over after a maximum of 45 minutes. It may be necessary to record extra images for specific diagnostic tasks, which may prolong the procedure. Why are we given headphones during the procedure? The many brief changes in the powerful magnetic field lead to very loud banging noises. These noises recur during all additional measurements throughout the procedure. Can I have an MRI scan if I am highly claustrophobic? During the procedure, the body lies in a bright cylinder with a diameter of approximately 70 cm. Patients who are claustrophobic should make special preparations for this procedure. Possible options include autogenic training, but drugs can also help reduce the claustrophobic sensations. It is often possible to perform the procedure without any problems with just a few drops of an anti-anxiety drug. Many patients even find that they doze off during the procedure. If, despite all this, you still experience claustrophobic sensations, press the ball in your hand and the procedure will be halted immediately. You can also talk to the technicians at all times via the microphone close to your head. Generated from XML by patientinfo.myesr.org. Copyright © European Society of Radiology (ESR) http://www.myesr.org

Should an MRI brain scan be performed as a screening test like a blood test, for example (once a year)? No. This very expensive process is not suitable for use as a preventive measure. It should only be performed if certain conditions are fulfilled and your doctor feels that it is justified. Do I have to be an in-patient in the hospital to have an MRI brain scan? No, the procedure can also be performed if you are an out-patient. You can go home again afterwards as long as there are no other medical reasons why you should not do so. Which patients should not undergo this procedure? As a general rule, this procedure is suitable for all patients. Pregnant women and children should have MRI scans rather than any other form of scan, as X-rays and computer tomography can be particularly dangerous for these patients. Use of this method should be considered very carefully before undertaking the procedure in the following cases and preparatory measures should be taken if applicable: Contrast agent allergies, implants or restricted kidney function (renal failure). Please let the radiologist or the MRI technician team know if this applies to you. What do I need to bring with me? You should bring up-to-date lab results (no more than 4 weeks old), showing results for the kidneys and thyroid gland in particular. If you have implants, please bring your transplant documents and any previous test results if applicable. How much radiation will I be exposed to? MRI does not lead to any radiation exposure. It uses electromagnetic waves, which do not harm the body.

Citations 1 - Team General Hospital Vienna 1

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