Bones, Joints and Soft Tissue MRI
What is magnetic resonance imaging (MRI)?
Magnetic resonance imaging (MRI) uses a large magnet, radiofrequencies (sound), and a computer to make detailed pictures of organs and structures within the body.
The MRI machine is a large, doughnut-shaped machine that creates a strong magnetic field around the person being examined. Because MRI uses magnetic fields and sound waves to take pictures of the body there are no biological side-effects as no radiation is used, unlike with X-ray or CT
Why do I need a Bone, Joint and Soft Tissue MRI?
MRI may be used to look at bones, joints, and soft tissues such as cartilage, muscles, and tendons for things like:
- Injuries, such as fractures or tears to a tendon, ligament, or cartilage
- Structural abnormalities due to aging
- Infection like osteomyelitis
- Inflammatory disease
- Congenital abnormalities (those you’re born with)
- Osteonecrosis (bone cell death caused by a poor blood supply to the area)
- Bone marrow disease
- Degenerative joint problems, like arthritis
- Herniation or degeneration of disks of the spinal cord
- Assessment after surgical procedures
Your referrer may have other reasons to recommend an MRI scan of the bones, joints, or soft tissue.
Because of the strong magnet in an MRI scanner, MRI cannot be used if you have:
- Implanted pacemaker or cardiac defibrillator
- Some intracranial aneurysm clips
- Cochlear implants
- Certain prosthetic devices
- Implanted medicine infusion pumps or medicine ports
- Bone-growth stimulators
- Certain intrauterine contraceptive devices
- Any other type of iron-based metal implants
- Tattoos or body piercings
- Internal metal objects or fragments, such as bullets or shrapnel, surgical clips, pins, plates, screws, metal sutures, or wire mesh
Tell your clinician if you are pregnant or think you may be. In general, there is no known risk of MRI in pregnancy. But in the first trimester, MRI should only be used to look at very important problems or suspected problems.
If contrast dye is used, there is a risk for allergic reaction to the dye. Tell your provider if you are allergic or sensitive to medicines, contrast dye, or iodine.
Nephrogenic systemic fibrosis (NSF) is a very rare but serious complication of MRI contrast use in people with kidney disease or kidney failure. If you have a history of kidney disease, kidney failure, kidney transplant, liver disease, or are on dialysis, be sure to tell the MRI radiographer before getting the contrast dye.
There may be other risks depending on your specific health condition. Be certain the Radiographer knows about all of your health conditions.
Tell the radiographer doing the test if you:
- Have ever had an imaging test (like MRI or CT) with contrast dye
- Are allergic to contrast dye or any medicines
- Have a serious health problem. This includes diabetes or kidney disease
- Are pregnant or may be pregnant or are breastfeeding
- Have any implanted device or metal clips or pins in your body
How do I get ready for a Bone, Joint and Soft Tissue MRI?
The radiographer will explain the procedure to you and give you a chance to ask any questions.
Generally, there is no special restriction on diet or activity before an MRI scan.
Before the MRI scan, it is very important that you tell the radiographer if any of these apply to you:
- You are claustrophobic and think that you will be unable to lie still inside the scanning machine
- You have a pacemaker or have had heart valves replaced
- You have any type of implanted pump, such as an insulin pump
- You have metal plates, pins, metal implants, surgical staples, or aneurysm clips
- You have any metallic fragments anywhere in the body
- You have permanent eyeliner or tattoos
- You are pregnant or think you may be pregnant
- You ever had a bullet wound
- You have ever worked with metal (for example, a metal grinder or welder)
- You have any body piercings
- You have an intrauterine device (IUD)
- You are wearing a medicine patch
If you are taking a sedative before the procedure, you should plan to have someone accompany you home afterward.
What happens during a Bone, Joint and Soft Tissue MRI?
Generally, MRI of the bones, joints, or soft tissue follows this process:
- You will be asked to remove any clothing, jewellery, eyeglasses, hearing aids, hairpins, removable dental work, or other objects that may get in the way of the procedure
- If you are asked to remove clothing, you will be given a gown to wear and your belongings will be locked away safely in a locker
- If you are to have an MRI scan with contrast, an intravenous (IV) line will be inserted in your hand or arm for injection of the contrast dye
- You will lie on a narrow table that slides into the large circular opening of the scanning machine. Pillows and straps may be used to help reduce movement during the scan
- The radiographer will be in another room where the scanner controls are located. But you will be in constant sight of the radiographer through a window. Speakers inside the scanner allow the radiographer to speak with you and hear you. You will have a call button so that you can let the radiographer know if you have any problems during the scan. The radiographer will be watching you at all times and will be in constant communication
- A special camera called a surface coil may be placed over the area to be examined if it is a relatively small area, such as a joint
- You will be given earplugs or headphones to wear to help block out the noise from the scanner. The headphones provide music for you to listen to put you may not always be able to hear this because of the noise of the machine. During the scanning process, you will hear different clicking and thumping noises as the magnetic field is created and pulses of radio waves are sent from the scanner
- It is important for you to stay very still during the exam. Any movement could affect the quality of the scan
- At certain times, you may be told to hold your breath, or to not breathe for a few seconds, depending on the body part being examined. You will then be told when you can breathe. You should not have to hold your breath for longer than a few seconds
- Once the scan is done, the table will slide out of the scanner and you will be helped off the table
- If an IV line was put in, it will be removed
While the MRI scan itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly if you’ve recently been injured or had surgery. The radiographer will use all possible comfort measures and do the scan as quickly as possible to minimize any discomfort or pain. Please take your regular medication on the day of the MRI scan.
On occasion, some people with metal fillings in their teeth may feel some slight tingling of the teeth during the scan.
What happens after a Bone, Joint and Soft Tissue MRI?
Move slowly when getting up from the scanner table so you don't have any dizziness or light-headedness from lying flat for the length of the procedure.
If any sedatives were used for the scan, you may need to rest until the sedatives have worn off. You will also need someone to drive you home.
If contrast dye is used, you may be watched for some time for any side effects or reactions to the contrast dye, such as itching, swelling, rash, or trouble breathing.
If you notice any pain, redness, or swelling at the IV site after you go home, contact your GP. This could be a sign of infection or other type of reaction.
Otherwise, there is no special type of care required after a MRI scan of the bones, joints, and soft tissues. You may go back to your usual diet and activities, unless the radiographer tells you differently.
The radiographer may give you other instructions after the procedure, depending on your particular situation.