MRI Scans - Information for Patients

  • What is MRI?
  • Why do I need MRI?
  • What happens in an MRI?
  • How do I prepare?
  • Any risks or side effects?
  • MRI Safety

What is MRI?

Magnetic resonance imaging (MRI) is a technique used to image your brain and body which uses radio waves in a strong magnetic field to produce images. Radiologists (Doctors specially trained in image interpretation and diagnosis) review and report their findings to your doctor.

The images are produced without using ionising radiation and therefore cause no damage to the tissues examined. MRI is used to examine delicate structures in the head and brain, the soft tissues around and in joints and many other organs such as kidneys and liver which are difficult to examine using other methods. The test is sensitive to subtle structural changes in tissues, not detected by other means of imaging or examination.

Your doctor will have requested the MRI (or CT) scan depending on the diagnoses he or she is considering in your specific case.

Why do I need MRI?

In the same way that an X-Ray would be used to detect a possible bone break, an MRI is used as a very accurate method of disease detection throughout the body. Surgery can be deferred or more accurately directed when your consultant has read the results of your MRI scan.

MRI scans are useful in a number of areas.

Evaluating injuries

Torn knee ligaments or cartilages show up well on an MRI, helping your doctor decide whether or not you need surgery. MRI is also useful for injuries involving the shoulder, back, or neck.

Evaluating joints and soft tissues

MRI is of particular use in the evaluation of tendons, ligaments and cartilage structures in and around most joints. It is excellent at evaluating muscle swellings or masses. Even subtle fractures such as scaphoid fractures can be detected by MRI. The knee is probably the joint most imaged by MRI (cartilage and ligament tears). MRI is also used to detect cartilage tears and soft tissue injury in the shoulder joint. MRI of hips is excellent at picking up a hip condition called avascular necrosis.

Diagnosing brain disorders

MRI can give very detailed images of the brain. A routine MRI brain scan takes approximately 15 minutes. MRI is now routinely used in the diagnosis of many different brain disorders, including multiple sclerosis, brain tumours, strokes, dementia, vertigo and tinnitus, and epilepsy.

Viewing the spine

MRI can picture large areas of the spine in a short period of time. It takes approximately 15 minutes each to scan the cervical, thoracic and lumbar spine. MRI is excellent for detecting degenerative disease in the spine. It can accurately show disc disease (‘prolapsed disc’ or ‘slipped disc’), the level at which disc disease occurs, and if a disc is compressing spinal nerves.

Analysing the size and location of tumours

Tumours in various parts of the body can be detected and measured by MRI. Repeat MRI scans are used to show shrinking or decrease in size of the tumour after treatment and to rule out tumour recurrence after surgery.

Assessing disorders of the eyes and ears

MRI is a valuable diagnostic tool in the assessment of inaccessible areas like the back of the eye or inner ear.

 


What happens in an MRI exam?

You will be asked to lie down on a special bed that moves into the wide bore magnet which is open on both ends thus minimising any feeling of claustrophobia. There will be plenty of light and air and you will not be left alone. Help and assistance will be available throughout the procedure.

Most MRI studies take between 30 and 60 minutes. You will be encouraged to stay still throughout the examination as this helps to obtain the clearest images. You will hear loud knocking and a whirring sound while the pictures are being taken. You usually wear earplugs so that the noise doesn't sound so loud. As there is no radiation, the scanning room is perfectly safe, so you may be allowed to bring a friend.

Children can have a parent with them. MRI scans require specialist interpretation, so you will not know your results immediately. The results will be sent to your doctor and you should arrange an appointment with your doctor to discuss the results.

 

Our Scanner : the Siemens Magnetom Espree

Cutting Edge Imaging

At Merlin Park Imaging Centre we have invested heavily in cutting edge MRI equipment to ensure you have the best scan experience possible while providing your consultant with high quality diagnostic information.

For more information on the benefits of our scanner, visit the Wide Bore MRI page

 

How do I prepare for the scan?

No special preparation is needed before an MRI scan. You may eat normally and take your usual medications. If you are having a scan of the lower body (pelvis or abdomen), you will be asked not to eat or drink for about five hours before your appointment.

Wear loose, comfortable clothing without metal fastenings such as zippers or clasps because metal will interfere with the test (don’t forget metal underwire bras). Do not wear jewellery. Tell the doctor if you have any metal in your body (such as plates, surgical clips, certain artificial heart valves, or screws from a previous surgery).

Before You Attend

When you come for your MRI you will be asked to fill in a safety questionnaire, a sample of which is provided below. Please take time to read through it before your scan.

Safety Questionnaire

Download now

 

 

 

 

 

 

 

Are there any risks or side effects?

There are no known complications of MRI scanning to worry about, however we do need to know about some medical conditions to avoid risk:

Cochlear Implants, Pacemakers and other devices

If you have a pacemaker or cochlear implant, unfortunately we cannot risk scanning you since the pacemaker is sensitive to magnetic fields and its function may be affected. Most medical devices are safe to place in the magnet, since they are not ferromagnetic. Some metals may become heated, please advise us of any such devices or treatments you may have had.

Impaired Renal Function

Sometimes we may need to repeat certain scans with intravenous contrast containing Gadolinium, a rare metal which allows us to see blood vessels and inflammation more clearly. In this case it will be important to know that you do not have any disturbance of kidney (renal) function. Very occasionally in persons with significantly impaired renal function a complication could occur following injection. Please advise us if this applies to you so we can avoid
injections.

Nephrogenic Systemic Fibrosis

Nephrogenic systemic fibrosis (NSF) is an extremely rare complication that has been described following intravenous administration of gadolinium contrast agents used for MRI. NSF is typically described in patients on dialysis with severe renal failure (GFR < 30 mL/min/1.73 m2) and with uses of larger doses of contrast. To minimize any potential risk MPIC utilizes standard small contrast doses when contrast is deemed necessary and a gadolinium contrast agent (Gadoterate meglumine, Gd-DOTA) that has no documented case of NSF to date.

First trimester of Pregnancy

Please let us know if you could be pregnant; as a precaution pregnant patients are not scanned during the first trimester (14 weeks). This is to avoid any potential risk to the developing fetus at this most sensitive time.

Allergies

Please notify us in advance if you have a history of allergies to contrast.

 

 

 

MRI Safety

There are no known complications of MRI scanning to worry about, however we do need to know about some medical conditions to avoid risk:

Cochlear Implants, Pacemakers and other devices

If a patient has a pacemaker or cochlear implant, unfortunately we cannot risk scanning them since the pacemaker is sensitive to magnetic fields and its function may be affected. Most medical devices are safe to place in the magnet, since they are not ferromagnetic. Some metals may become heated, please advise us of any such devices or treatments they may have had.

Impaired Renal Function

Sometimes we may need to repeat certain scans with intravenous contrast containing Gadolinium, a rare metal which allows us to see blood vessels and inflammation more clearly. In this case it will be important to know that patients do not have any disturbance of kidney (renal) function. Very occasionally in persons with significantly impaired renal function a complication could occur following injection. Please advise us if this applies to your patient so we can avoid
injections.

Nephrogenic Systemic Fibrosis

Nephrogenic systemic fibrosis (NSF) is an extremely rare complication that has been described following intravenous administration of gadolinium contrast agents used for MRI. NSF is typically described in patients on dialysis with severe renal failure (GFR < 30 mL/min/1.73 m2) and with uses of larger doses of contrast. To minimize any potential risk MPIC utilizes standard small contrast doses when contrast is deemed necessary and a gadolinium contrast agent (Gadoterate meglumine, Gd-DOTA) that has no documented case of NSF to date.

First trimester of Pregnancy

Please let us know if a patient could be pregnant; as a precaution pregnant patients are not scanned during the first trimester (14 weeks). This is to avoid any potential risk to the developing fetus at this most sensitive time.

Allergies

Please notify us in advance if patients have a history of allergies to contrast.