MRI or Magnetic Resonance Imaging is a Medical Imaging Technique used in Radiology to form pictures of the anatomy and the physiological processes of the body.
This procedure does not include any Radiation as MRI scanners use magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. At Oran Park Radiology, MRI scans are performed by highly qualified and accredited MRI Radiographers and reported by our specialised Radiologists.
You will need a referral from your GP or specialist and you will need to answer some important medical history and safety questions when making an appointment.
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What is an MRI scan?
Magnetic Resonance Imaging (MRI) is a scanning procedure that uses strong magnets and radio-frequency pulses to generate signals from the body. These signals are detected by a radio detector and processed by a computer to create images (or pictures) of the inside of your body. Shire medical imaging is totally focused on providing the best image quality for all of our patients.
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Preparation
- The request form – The first step in the process is for us to find out what is on the request form that your doctor gave you for this test. This may involve you coming into our rooms here at Oran Park Radiology and showing the form to our front desk staff. Or you can fax or email the form to us (see contact us – Oran Park Radiology, Oran Park). Or maybe you can read out what is on the form over the phone to one of our front desk staff. We need to know what kind of test is requested, what part of the body the test is requested for and what the problems/suspected diseases/symptoms are..
- Patient Questionnaire – to make the MRI scan as safe as possible, and to minimise any side effects or complications, we need to know a few things about your medical history. This may include if you have any kidney disease, thyroid disease, blood diseases, cancers, allergies or diabetes. It would also be beneficial for us to know if you have had any MRI scans before, to obtain previous examination results for comparison and if you have had any bad reactions to previous CT contrast agents. (eg IV iodine).
- Fasting – Sometimes the examinations can give you a nauseous feeling. Most people do not vomit, but to be on the safe side, we advise that you refrain from eating or drinking anything for 4 hours before a CT examination, just in case. If you have a medical disorder that makes this difficult, for instance diabetes, please speak to the booking staff who will advise on the best way to proceed.
- Blood tests – patients with kidney disease or anyone with reduced kidney function (even if you do not have any symptoms associated with it) are at increased risk with some of the MRI examinations. So we believe that it is important to check on the kidney function before the test so that we can adjust the procedures to minimise the risk of kidney trouble. So we will advise you and your doctor to obtain a blood test for the kidneys if need be.
- Adjusting medications – Some medications can, in combination with the MRI contrast agents, cause medical problems after a MRI examination. That is why we will ask you which medications you are taking. We can advise you and your doctor how to best manage the medications around the time (before and after) the MRI examination. These medications include
- Metformin
- Blood thinners
- Please see information about your specific examination for details on pre examination preparation.
Safety in the MRI scanner is vital. The magnetic fields can attract and interfere with metal objects that you might have in or on you (including electronic and magnetic devices). Some of these interactions can cause harm or death (see the section on risks of MRI below).To ensure it is safe for you to have an MRI, you will be required to complete a safety questionnaire. If a friend or relative will be in the scanning room with you, they will also need to complete a safety questionnaire.
Objects in your body that can cause particular harm or be damaged include: pacemakers, aneurysm clips, heart valve replacements, neurostimulators, cochlear implants, metal fragments in the eye, metal foreign bodies, magnetic dental implants and drug infusion pumps. Some of these implants, particularly more recent devices, might be safe to go into the MRI scanner, but have to be accurately identified for the scan to proceed.You should take any documents about your implants to the appointment. These can help to correctly identify the type of implant to assess if it is safe for you to have the MRI.
It is important that you do not wear any makeup or hairspray, as many of these products have tiny metal particles that could interfere with the scan and reduce the quality of the images. They might cause the area to heat up and, on the rare occasion, burn your skin.
You will not be able to take anything with you into the scan room, and there are usually lockers available. It is easier if you leave objects such as watches, jewellery, mobile phones, belts, safety pins, hairpins and credit cards at home.
If you are pregnant, please discuss this with your doctor and tell the radiology practice before having the scan.
If you are claustrophobic (a fear of small or enclosed spaces) and think you might not be able to proceed with the scan, advise your doctor or the MRI facility when making your appointment.Fasting (going without food) for a MRI procedure might be required in some cases. When you make your MRI appointment, you will be advised of any fasting requirements.
Continue to take all your normal medications, unless you are otherwise advised when you make the booking for your MRI scan.
Please bring any previous MRI, X-ray, computed tomography or ultrasound films. The radiologist might like to review the older studies or see if your condition has changed since your last scan.
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Iodine Contrast
Before any MRI scan, you will be asked a number of questions about your medical history, and any implants you might have, to make sure that you will not be at risk from the strong magnetic fields of the scanner. You will also be asked about conditions that might mean a gadolinium injection would not be recommended (e.g. pregnancy, previous allergic reaction, severe kidney disease). If you have any of these conditions, then you will not be given gadolinium, but if there is no condition preventing injection, you might be asked to sign a consent form in case gadolinium is required.
Usually, you will be advised by the technologist or nurse before you have the MRI scan that it is recommended that gadolinium contrast medium be injected during the examination. As with any medical procedure, you have the right to seek further advice and/or to decline a gadolinium injection. The technologist who carries out the MRI scan, a nurse or a radiologist will give you the injection.Some people get a hot feeling all over the body after IV injection of Iodine. This does not last long and it is not dangerous. Some people get a feeling of wetting themselves (although it is very rare to actually be incontinent during an MRI examination). But this also is not dangerous and passes quickly. Some people get a slight nauseous feeling, but this also passes relatively quickly. (this can occur with both intravenous or oral Iodine). It is rare to actually vomit during or after a CT examination.
A few people have an allergy to intravenous Iodine injections. This is different and unrelated to an allergy to antiseptic iodine that is put onto the skin. However, this allergy can be dangerous. So it is important for the technical staff and the radiologist doctor to be told about any allergies you have.
Mild reactions include flushing, nausea, pruritus, vomiting, headache and mild urticaria. They are usually self limited and resolve without specific treatment. Mild reactions may be seen in up to 3% of patients after non-ionic low-osmolality contrast agent administration.
Moderate contrast reactions include severe vomiting, marked urticaria, bronchospasm, facial/laryngeal oedema and vasovagal attacks.
Severe contrast reactions include hypovolaemic shock, respiratory arrest, cardiac arrest, pulmonary oedema and convulsions. Severe reactions are uncommon, occurring in 0.04% to 0.004% of non-ionic low osmolar iodinated contrast injections (i.e. 1 in 2,500 to 1 in 25,000 contrast injections). The risk of death is rare (1 in 170,000).
Other possible, although rare, complications and side effects of an intravenous injection of iodine include extravasation (where the iodine comes out of the vein into the tissues in the arm), infection or bleeding from the puncture site, which may require treatment.
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The MRI Examination
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The MRI procedure will be thoroughly explained to you. If you have any questions, please ask the radiographer (medical imaging technologist), who will be operating the MRI scanner, as it is important that you are comfortable and know what will be happening. The radiographer will be able to see you from the control room throughout the scan. You will usually be asked to change into a gown. You will be asked to lie on the scan table and given a buzzer to hold. When you squeeze it, an alarm sounds in the control room and you will be able to talk to the radiographer. The MRI scanner is very noisy during the scans. It is at a noise level that can damage your hearing. You will be given earplugs or headphones to reduce the noise to safe levels.
Depending on the type of MRI you are having and your particular situation, at this point you might have:
• leads placed on your chest to monitor your heartbeat if having a heart scan;
• a small plastic tube (pulse oximeter) taped on your finger to check your breathing and heart rate if having sedative (calming) medication; and/or
• a needle inserted into a vein in your arm if any medication is required during the scan.
The most common medication injected is a contrast agent or ‘dye’ called gadolinium contrast medium. This highlights the part of the body being scanned, which can give more information to the radiologist who is assessing your problem.The part of your body to be scanned will be carefully positioned and gently secured, so you are comfortable and more likely to remain still. This part will then have special antennae (coils) positioned around it to pick up signals from your body for the computer to create images. The coils are usually encased in a plastic pad or frame. Depending on the part of the body being scanned, they might be wrapped around your shoulder or lie on top of your stomach. A frame containing the coils can be used; for example, around your knee or wrist, and also for your head and upper neck. Some coils are in the mattress of the scan bed, used when your back is being scanned. The scan table will then move into the centre of the machine. Your head might be inside or outside the scanner, depending on the part of the body being scanned.
When the scan begins, you will hear a loud knocking noise that continues during each scan. Scanning is not continuous, and each scan varies in length from about 1 to several minutes, with a break in between. You will be able to talk to the radiographer between each scan and can press the buzzer if you are not comfortable or want to come out of the machine at any time.
The scanning process is painless. You might feel warm during scanning. If you do feel anything at all, it is important you tell the radiographer carrying out the scan.
You need to lie still and hold your position during the scan. In general, you can breathe normally. Occasionally, during some types of MRI, you will need to hold your breath. Breathing and movement can make the images blurry and assessment of your problem more difficult.
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After the MRI Test
There are no after effects of the MRI itself. You will be able to carry on your day as planned once the test has been completed. If you are given any medication during the scan, you might experience after effects. The staff looking after you will discuss any after affects with you, and will help you if they do occur.