This section contains listed questions and answers, all supposed to be commonly asked in some context, and pertaining to a particular topic.
MRI stands for magnetic resonance imaging. MRI scan uses a combination of a strong magnet and radio waves to produce detailed pictures of the anatomy and the physiological processes inside of your body.
The MRI scanner is operated by a radiographer, who is trained in carrying out X-rays and similar procedures. They control the scanner using a computer, which is in a different room to keep it away from the magnetic field generated by the scanner.
An MRI scan can help to find out what is causing your problem and help your doctor to find the best treatment for you. An MRI scan provides much more detailed pictures of your body than an ordinary x-ray. It is particularly good at identifying problems in the spine, the brain and blood vessels. It is also helpful for looking at other parts of the body, often when other types of scan have not given a full picture. Unlike x-rays and CT scans do not use radiation.
MRI is a very safe procedure for most patients. However, patients with heart pacemakers and certain other surgical implants, for example a cochlear implant, cannot be scanned. There may also be a problem if you have ever had metal fragments in your eyes. You must let us know beforehand if this is the case. (Contact details on your appointment letter and at the bottom of this information) You will be asked to complete and sign a safety questionnaire before your scan to make sure it is safe for you to be scanned.
If you cannot have a scan, for example if you have a pacemaker, the radiologist may suggest an alternative type of imaging. This could be a CT scan or an ultrasound scan.
Unfortunately, there is no simple answer. Let a doctor know about the pregnancy before the scan. Typically, doctors do not recommend contrast material for women who are pregnant unless the scan is clinically urgent. The doctor who refers you for the scan, along with the radiologist (doctor who uses x-ray to diagnose and treat illnesses) will decide whether they believe your scan is necessary. Many pregnant women have had MRI scans with no reported problems. If you have been referred for an MRI scan when you are pregnant and would like further information, please do not hesitate to call us (contact details at the bottom of this information).
In most cases you do not need to do anything to prepare for the scan. You can eat and drink as normal. If you are taking any medication, please continue to take this.
We may ask you to change into a hospital gown so it is advisable if you can wear clothes that you can easily change out of.
You will need to take off your watch and take any credit cards or travel cards with magnetic strips out of your pockets. The scanner can affect these and stop them from working. Hairclips and wigs must also be removed if they contain metal.
Before the scan, you will be given the opportunity to ask any questions that you may have. During an MRI scan, we will ask you to lie on the scanner bed where you will be made as comfortable as possible. Depending on the part of your body being scanned, you will be moved into the scanner either head first or feet first.
Once you are positioned correctly, we will move you into the scanner – the part of your body that we are scanning must be in the centre of the machine. For scans of the chest or abdomen, you may be asked to hold your breath for short periods of time.
When the scanner is working, it makes a loud banging noise. We will give you headphones to wear to reduce the noise. You can request to listen to music while you are being scanned. You will also be given a buzzer to press if you need to attract our attention during your scan.
The scan is run by a certified technologist specializing in the specific modality of the diagnostic test.
MRI scans typically take longer and are louder, and they usually need the patient to enter a narrow, confining tube. If you are claustrophobic we recommend that you speak with your doctor who may prescribe medication to help you relax.
It is important to keep as still as possible during the scan. Any movement will distort the scanner and, therefore, the images produced will be blurry.
This depends on which part of your body is being scanned and the information that your doctor needs. The radiographer will tell you how long he/she expects your scan to take. Most scans take between 20 and 30 minutes, although some can take an hour. In particularly long MRI scans, the MRI technician may allow a short break halfway through the procedure.
The radiographer will talk to you during the scan to let you know what is happening. If you are particularly anxious, a friend or relative may be able stay in the room during the scan.
The scan should be completely painless. The most difficult part is keeping still. Make sure you are as comfortable as possible before we start and try to relax. The scanner is a short tunnel which is open at both ends.
If we are scanning certain areas of your body, a contrast dye can improve diagnostic accuracy by highlighting certain tissues. The injection will be given by inserting a small needle into a vein in your arm or your hand.
If contrast dye is used, there is a minimal risk for allergic reaction to the dye. MRI contrast may also have an effect on other conditions such as allergies, asthma, anaemia, hypotension (low blood pressure), and sickle cell disease. Mild swelling and tenderness may be present at the site of the injection for a few days after the injection as with all types of intravenous injections. Be sure to discuss any concerns with your physician prior to the procedure.
Current guidelines state that it is safe to breastfeed following the injection of contrast dye as so little dye is passed to the baby via the breastmilk. Alternatively, if you prefer, you can express and discard the breast milk for 24hrs following the scan.
As soon as the scan is finished, you can go home, or back to your ward if you are staying in the hospital. You can eat and drink as normal and resume your usual activities. The pictures taken during the scan are carefully studied by the radiologist who will produce a detailed report.
The only test which will require transportation would be an MRI in which a sedative was administered.
The results will be sent to the doctor who referred you for the scan if possible. Most results are available for collection within 24 hours. For more urgent problems, they may be available sooner.
No
Yes, CT imaging is considered a safe examination. In general, the diagnostic benefit of a CT scan usually outweighs the risk of x-ray radiation exposure or injections of imaging contrast and use of sedatives during the scan. Patients should inform the radiologist or technologist if they have a history of allergies (especially to medications, previous iodine injections for example)
Contrast are pharmaceutical agents in the form of a liquid dye. CT contrast is used to make specific organs, blood vessels and/or tissue types "stand out" with more image contrast to better show the presence of disease or injury. During most CT scans, patients may be asked to take a the contrast agent either orally, rectally or via injection.
Not everyone needs an injection for CT scan. This is only done when the radiologist or the referring doctor have determined that it is necessary.
This depends on the type of scan you will receive. Ct scans typically last between 10 to 45 minutes. A few CT examinations take longer than 45 minutes.
It is important that you do not move the body part being imaged, until the entire CT exam is complete.
Yes
No, CT uses x-ray and only the person being scanned should be in the CT scanner room during the examination.
Patients are advised to wait for 24 hours after receiving the CT contrast injection before breast feeding again. Patients may wish to pump breast milk prior to the CT exam and store it for use during this 24-hour period. Always check with the radiologist and the imaging centre for their specific recommendations.
Pregnant woman should never have a CT exam or any x-ray examination, Pregnant women should always inform their referring doctor that they are pregnant or may be pregnant.
