MRI

1. MR Angio
2. MRI Body & Parts
3. MRI Brain
4. MRI Bone & Joint
5. MRI Cardiac
6. MRI Spine

You’ve probably heard about the test called magnetic resonance imaging or MRI. In this test, radio waves, a magnetic field, and a computer create a scan of your body parts to look for health problems.

Magnetic resonance angiography–also called a magnetic resonance angiogram or MRA–is a type of MRI that looks specifically at the body’s blood vessels. Unlike a traditional angiogram, which requires inserting a catheter into the body, magnetic resonance angiography is a far less invasive and less painful test.

During magnetic resonance angiography, you lie flat inside the magnetic resonance imaging scanner. This is a large, tunnel-like tube. In some cases, a special dye, known as contrast, may be added to your bloodstream to make your blood vessels easier to see. When needed, the contrast is given with an intravenous (IV) needle.

Why might I need Magnetic Resonance Angiography?

If your healthcare provider believes that you may have a narrowing or blockage of blood vessels somewhere in your body, he or she may recommend magnetic resonance angiography. Other conditions that your healthcare provider can look for during this test include:

• An aneurysm or weakness in the wall of an artery
• A narrowing of the aorta, or aortic coarctation
• Bleeding in and along the wall of the aorta, or aortic dissection
• To find the cause of a stroke
• Signs of heart disease
• Narrowing or blockage of the vessels in the arms or legs
• Renal artery stenosis, a narrowing of the blood vessels in the kidneys that can lead to high blood pressure and even renal failure

What are the risks of magnetic resonance angiography?

If a dye is needed to make the blood vessels easier to see during the test, you may experience a bit of discomfort because of the insertion of the IV.

You might also experience some anxiety when placed inside the MRI scanner, which is a small, narrow space. If you think you might be claustrophobic, be sure to inform your healthcare provider of this in advance. You may be given a mild sedative to make being in the MRI scanner more bearable.

Some potential risks of magnetic resonance angiography include:

• You may suffer bodily harm from having metal objects in pockets or clothing or metal implants (such as a pacemaker or bullet fragment) within your body. Before you undergo the test, you will be asked a series of detailed questions about any metal you may have in your body.
• If you have a problem with your kidneys, you are at risk of developing a severe reaction after receiving the MRI contrast dye that is used to make blood vessels more visible. This reaction can affect tissues throughout the entire the body including the skin, joints, liver, and lungs. If you have a history of kidney disease, your healthcare provider may decide that an MRI or MRA is not for you.
• Pregnant women may have additional risks in the MRI scanner. Make sure to tell your healthcare provider if you are or might be pregnant.
• You may be at risk for other complications, depending on your specific medical condition. Be sure to discuss any concerns with your healthcare provider before the test.

How do I prepare for an MRA study?

• Eat/Drink: You may eat, drink and take medications as usual.
• CLOTHING: You must completely change into a patient gown and lock up all personal belongings. A gown and locker will be provided for you. Please remove all piercings and leave all jewellery and valuables at home.
• What to Expect: Imaging takes place inside of a large tube-like structure, open on both ends. You must lie perfectly still for quality images. The machine is very loud, so earplugs are required and will be provided to you.
• Contrast: Your exam may include an injection of a contrast agent. A contrast agent is a special liquid that is injected through an intravenous (IV) line, a small tube placed in a vein. Some people may notice discomfort, tingling or warmth in the lips, metallic taste in the mouth, tingling in the arm, nausea or headache. These symptoms go away quickly.
• Allergy: If you’ve had an allergic reaction to contrast that required medical treatment, contact your ordering physician to obtain the recommended prescription to take by mouth 24, 12 and two hours prior to the exam.
• Anxiety: If you require anti-anxiety medication due to claustrophobia, contact your ordering physician for a prescription. Please note, you will need someone to drive you home.
• Strong Magnetic Environment: If you have metal within your body that was not disclosed prior to your appointment, your study may be delayed, rescheduled or cancelled upon your arrival until further information can be obtained.

Your doctor may suggest additional preparation depending on your particular situation.

What happens during magnetic resonance angiography?

Magnetic resonance angiography may be done on an outpatient basis or during a hospital stay. Generally, magnetic resonance angiography follows this process:

1. You will remove any clothing, jewellery, or other objects that may interfere with the scan and put on a gown.
2. If you need a contrast dye to make blood vessels easier to see, this will be given through an IV.
3. You will be positioned on an exam table directly outside the MRI scanner.
4. The table will slide into position, placing you inside the MRI scanner.
5. You will need to lie still during the scanning process. Any movements can blur the images and cause the results to be less accurate.
6. The MRI scanner typically makes a lot of noise, including loud humming noises, so don’t be alarmed.
7. The full scan may take an hour or longer. This will depend on the type and number of blood vessels that your healthcare provider wishes to examine.

The scan typically causes no side effects or complications. If it is done on an outpatient basis, you are generally free to leave after the magnetic resonance angiography. Your healthcare provider will likely schedule a follow-up appointment to review the results of the test.

What happens after magnetic resonance angiography?

Your healthcare provider will examine the images from the magnetic resonance angiography. If no blockages or irregularities are found, you have what’s called a normal test result. An abnormal result means that the healthcare provider noted an abnormality in one or more of the blood vessels in your body. This may suggest that you have hardening of the arteries, known as atherosclerosis, or another circulatory problem. Your healthcare provider will likely suggest additional tests or treatments based on the specific problem that is discovered.

Magnetic resonance imaging (MRI) of the body uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the inside of your body. It may be used to help diagnose or monitor treatment for a variety of conditions within the chest, abdomen and pelvis. If you’re pregnant, body MRI may be used to safely monitor your baby.

Tell your doctor about any health problems, recent surgeries or allergies and whether there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most orthopaedic implants pose no risk, but you should always tell the technologist if you have any devices or metal in your body. Guidelines about eating and drinking before your exam vary between facilities. Unless you are told otherwise, take your regular medications as usual. Leave jewellery at home and wear loose, comfortable clothing. You may be asked to wear a gown. If you have claustrophobia or anxiety, you may want to ask your doctor for a mild sedative prior to the exam.

Magnetic resonance imaging (MRI) is a non-invasive test used to diagnose medical conditions.

MRI uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of internal body structures. MRI does not use radiation (x-rays).

Detailed MR images allow doctors to examine the body and detect disease. The images can be reviewed on a computer monitor. They may also be sent electronically, printed or copied to a CD, or uploaded to a digital cloud server.

What are some common uses of the procedure?

MR imaging of the body is performed to evaluate:

• Organs of the upper body and abdomen—including the Face, chest, liver, biliary tract, kidneys, spleen, bowel, pancreas, and adrenal glands.
• Pelvic organs including the bladder and the reproductive organs such as the uterus and ovaries in females and the prostate gland in males.
• Lymph nodes.

Physicians use an MR examination to help diagnose or monitor treatment for conditions such as:

• Tumours of the chest, abdomen or pelvis.
• Diseases of the liver, such as cirrhosis, and abnormalities of the bile ducts and pancreas.
• Inflammatory bowel disease such as crohn’s disease and ulcerative colitis.
• Heart problems, such as congenital heart disease.
• Malformations of the blood vessels and inflammation of the vessels (vasculitis).
• A foetus in the womb of a pregnant woman.

How does the procedure work?

Unlike x-ray and computed tomography (CT) exams, MRI does not use radiation. Instead, radio waves re-align hydrogen atoms that naturally exist within the body. This does not cause any chemical changes in the tissues. As the hydrogen atoms return to their usual alignment, they emit different amounts of energy depending on the type of body tissue they are in. The scanner captures this energy and creates a picture using this information.

In most MRI units, the magnetic field is produced by passing an electric current through wire coils. Other coils are located in the machine and, in some cases, are placed around the part of the body being imaged. These coils send and receive radio waves, producing signals that are detected by the machine. The electric current does not come in contact with the patient.

A computer processes the signals and creates a series of images, each of which shows a thin slice of the body. These images can be studied from different angles by the radiologist.

MRI is able to tell the difference between diseased tissue and normal tissue better than x-ray, CT and ultrasound.

How is the procedure performed?

MRI exams may be done on an outpatient basis.

You will be positioned on the moveable exam table. Straps and bolsters may be used to help you stay still and maintain your position.

Devices that contain coils capable of sending and receiving radio waves may be placed around or next to the area of the body being scanned.

MRI exams generally include multiple runs (sequences), some of which may last several minutes.

If a contrast material is used, a doctor, nurse or technologist will insert an intravenous catheter (IV line) into a vein in your hand or arm that will be used to inject the contrast material.

You will be placed into the magnet of the MRI unit. The technologist will perform the exam while working at a computer outside of the room.

If a contrast material is used during the exam, it will be injected into the intravenous line (IV) after an initial series of scans. More images will be taken during or following the injection.

When the exam is complete, you may be asked to wait while the radiologist checks the images in case more are needed.

Your IV line will be removed after the exam is over.

Depending on the type of exam and the equipment used, the entire exam is usually completed in 30 to 50 minutes.

What will I experience during and after the procedure?

Most MRI exams are painless. However, some patients find it uncomfortable to remain still. Others may feel closed-in (claustrophobic) while in the MRI scanner. The scanner can be noisy. Sedation may be arranged for anxious patients, but fewer than one in 20 require it.

It is normal for the area of your body being imaged to feel slightly warm. If it bothers you, tell the radiologist or technologist. It is important that you remain perfectly still while the images are being taken. This is typically only a few seconds to a few minutes at a time. You will know when images are being recorded because you will hear and feel loud tapping or thumping sounds. These are made when the coils that generate the radio waves are activated. You will be provided with earplugs or headphones to reduce the sounds made by the scanner. You may be able to relax between imaging sequences. However, you will be asked to keep the same position without moving as much as possible.

You will usually be alone in the exam room. However, the technologist will be able to see, hear and speak with you at all times using a two-way intercom. Many facilities allow a friend or parent to stay in the room if they have also been screened for safety.

Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help pass the time.

In some cases, IV injection of contrast material may be given before the images are obtained. The IV needle may cause you some discomfort and you may experience some bruising. There is also a very small chance of skin irritation at the site of the IV tube insertion. Some patients may have a temporary metallic taste in their mouth after the contrast injection.

If you do not require sedation, no recovery period is necessary. You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, a few patients experience side effects from the contrast material. These may include nausea, headache and pain at the site of injection. It is very rare that patients experience hives, itchy eyes or other allergic reactions to the contrast material. If you have allergic symptoms, tell the technologist. A radiologist or other doctor will be available for immediate assistance.

Who interprets the results and how do I get them?

A radiologist, a doctor trained to supervise and interpret radiology exams, will analyze the images. The radiologist will send a signed report to your primary care or referring physician, who will share the results with you.

Follow-up exams may be needed. If so, your doctor will explain why. Sometimes a follow-up exam is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. A follow-up exam may also be done to see if there has been any change in an abnormality over time. Follow-up exams are sometimes the best way to see if treatment is working or if an abnormality is stable or has changed.

What are the benefits vs. risks?

Benefits

• MRI is a non-invasive imaging technique that does not involve exposure to radiation.
• MR images of the soft-tissue structures of the body—such as the heart, liver and many other organs— is more likely in some instances to identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many focal lesions and tumours.
• MRI has proven valuable in diagnosing a broad range of conditions, including cancer, heart and vascular disease, and muscular and bone abnormalities.
• MRI can detect abnormalities that might be obscured by bone with other imaging methods.
• MRI allows physicians to assess the biliary system noninvasively and without contrast injection.
• The MRI gadolinium contrast material is less likely to cause an allergic reaction than the iodine-based contrast materials used for x-rays and CT scanning.
• MRI provides a non-invasive alternative to x-ray, angiography and CT for diagnosing problems of the heart and blood vessels.

Risks

• The MRI exam poses almost no risk to the average patient when appropriate safety guidelines are followed.
• If sedation is used, there is a risk of using too much. However, your vital signs will be monitored to minimize this risk.
• The strong magnetic field is not harmful. However, it may cause implanted medical devices to malfunction or cause distortion of the images.
• Nephrogenic systemic fibrosis is a recognized, but rare, complication related to injection of gadolinium contrast. It usually occurs in patients with serious kidney disease. Your doctor will carefully assess your kidney function before considering a contrast injection.
• There is a very slight risk of an allergic reaction if contrast material is used. Such reactions are usually mild and controlled by medication. If you have an allergic reaction, a doctor will be available for immediate assistance.
• IV contrast manufacturers indicate mothers should not breastfeed their babies for 24-48 hours after contrast material is given. However, the most recent American College of Radiology (ACR) Manual on Contrast Media reports that studies show the amount of contrast absorbed by the infant during breastfeeding is extremely low. For further information please consult the ACR Manual on Contrast Media and its references.

What are the limitations of MRI of the Body?

• High-quality images depend on your ability to remain perfectly still and follow breath-holding instructions while the images are being recorded. If you are anxious, confused or in severe pain, you may find it difficult to lie still during imaging.
• A person who is very large may not fit into certain types of MRI machines. There are weight limits on the scanners.
• Implants and other metallic objects can make it difficult to obtain clear images. Patient movement can have the same effect.
• A very irregular heartbeat may affect the quality of images. This is because some techniques time the imaging based on the electrical activity of the heart.
• Breathing may cause artefacts, or image distortions, during MRIs of the chest, abdomen and pelvis. Bowel motion is another source of motion artefacts in abdomen and pelvic MRI studies. This is less of a problem with state-of-the art scanners and techniques.
• Although there is no reason to believe that MRI harms the foetus, pregnant women should not have an MRI exam during their first trimester unless medically necessary.
• MRI may not always distinguish between cancer tissue and fluid, known as edema.

MRI typically costs more and may take more time to perform than other imaging methods. Talk to your insurance provider if you have concerns about the cost of MRI.

Magnetic resonance imaging (MRI) of the brain is a safe and painless test that uses a magnetic field and radio waves to produce detailed images of the brain and the brain stem. An MRI differs from a CAT scan (also called a CT scan or a computed axial tomography scan) because it does not use radiation.

An MRI scanner consists of a large doughnut-shaped magnet that often has a tunnel in the centre. Patients are placed on a table that slides into the tunnel. Some centres have open MRI machines that have larger openings and are helpful for patients with claustrophobia. MRI machines are located in hospitals and radiology centres.

During the exam, radio waves manipulate the magnetic position of the atoms of the body, which are picked up by a powerful antenna and sent to a computer. The computer performs millions of calculations, resulting in clear, cross-sectional black and white images of the body. These images can be converted into three-dimensional (3-D) pictures of the scanned area. This helps pinpoint problems in the brain and the brain stem when the scan focuses on those areas.

Why It’s Done

MRI can detect a variety of conditions of the brain such as cysts, tumours, bleeding, swelling, developmental and structural abnormalities, infections, inflammatory conditions, or problems with the blood vessels. It can determine if a shunt is working and detect damage to the brain caused by an injury or a stroke.

MRI of the brain can be useful in evaluating problems such as persistent headaches, dizziness, weakness, and blurry vision or seizures, and it can help to detect certain chronic diseases of the nervous system, such as multiple sclerosis.

In some cases, MRI can provide clear images of parts of the brain that can’t be seen as well with an X-ray, CAT scan, or ultrasound, making it particularly valuable for diagnosing problems with the pituitary gland and brain stem.

Preparation

In many cases, a brain MRI requires no special preparation. However, the technician will have your child remove any objects containing metal (such as eyeglasses and jewellery) because they can produce a bright or blank spot on the diagnostic film. You’ll also be asked questions to make sure your child doesn’t have any internal metal clips from previous surgery or anything else that might cause a problem near a strong magnetic field. Electronic devices aren’t permitted in the MRI room.

To get the highest quality MRI results, your child will need to lie still during the scan. For this reason, sedation may be needed, especially for babies and young kids, who often have trouble staying still for the test. Sedation is also helpful for kids who have trouble relaxing in an enclosed space (claustrophobia).

Sedation medicines usually are given through an intravenous (IV) line (small tube in a vein) to help a child stay asleep during the entire test.

If your child will be sedated, food and liquids will be stopped at a certain point before the MRI to allow the stomach to empty. It’s important to notify the MRI technician of any illness, allergy, previous drug reactions, or pregnancy.

You can stay in the MRI room with your child until the test begins, and some centres let parents stay throughout the test. Otherwise, you’ll join the technician in an outer room or be asked to stay in a waiting room.

Procedure

An MRI of the brain usually takes 30-45 minutes to perform. Your child will lie on the movable scanning table while the technologist places him or her into position. A special plastic device called a coil may be placed around your child’s head. The table will slide into the tunnel and the technician will take images of the head. Each scan takes a few minutes.

To detect specific problems, your child may be given a contrast solution through an IV. The solution is painless as it goes into the vein. The contrast highlights certain areas of the brain, such as blood vessels, so doctors can see more detail in specific areas. The technician will ask if your child is allergic to any medications or food before the contrast solution is given. The contrast solution used in MRI tests is generally safe. However, allergic reactions can occur. Talk to your doctor about the benefits and risks of receiving contrast solution in your child’s case.

As the exam proceeds, your child will hear repetitive sounds from the machine, which are normal. Your child may be given headphones to listen to music or earplugs to block the noise, and will have access to a call button in case he or she becomes uneasy during the test. If sedated, your child will be monitored at all times and will be connected to a machine that checks the heartbeat, breathing, and oxygen level.

Once the exam is over, the technician will help your child off the table; if sedation was used, your child may be moved to a recovery area.

What to Expect

An MRI exam is painless. Your child may have to lie still on the MRI table for 30-45 minutes during the procedure, but there are brief breaks between each scan. If your child feels cold lying on the MRI table, a blanket can be provided.

Unless sedation was used or you are told otherwise, your child can immediately return to normal routines and diet. Most sedation wears off within 1-2 hours, and any contrast material given should pass through the body in about 24 hours.

Getting the Results

The MRI images will be viewed by a radiologist who’s specially trained in interpreting the scans. The radiologist will send a report to your doctor, who’ll discuss the results with you and explain what they mean. In most cases, results can’t be given directly to the patient or family at the time of the test. If the MRI was done on an emergency basis, the results can be made available quickly.

Risks

MRIs are safe and relatively easy. No health risks are associated with the magnetic field or radio waves, since the low-energy radio waves use no radiation. The procedure can be repeated without side effects.

If your child requires sedation, you may discuss the risks and benefits of sedation with your provider. Also, because contrast solutions can cause allergic reactions in some kids, be sure to check with your doctor before your child receives any solution. There should be medical staff on hand who are prepared to handle an allergic reaction.

If your child has decreased kidney function, this is an important medical condition to discuss with the radiologist and technician before receiving IV contrast since it may lead to some rare complications.

Helping Your Child

You can help your child prepare for an MRI by explaining the test in simple terms before the examination. Make sure to explain that pictures of the head will be taken and that the equipment will probably make knocking and buzzing noises.

It also may help to remind your child that you’ll be nearby during the entire test.

If an injection of contrast fluid or sedation is needed, you can tell your child that the initial sting of the needle will be brief and that the test itself is painless.

If your child will be awake for the test, be sure to explain the importance of lying still.

In orthopaedics, an MRI may be used to examine bones, joints, and soft tissues such as cartilage, muscles, and tendons for injuries or the presence of structural abnormalities or certain other conditions, such as tumours, inflammatory disease, congenital abnormalities, osteonecrosis, bone marrow disease, and herniation or degeneration of discs of the spinal cord. MRI may be used to assess the results of corrective orthopaedic procedures. Joint deterioration resulting from arthritis may be monitored by using magnetic resonance imaging.

There may be other reasons for your physician to recommend an MRI of the bones, joints, or soft tissue.

What are the risks of an MRI?

Because radiation is not used, there is no risk of exposure to ionizing radiation during an MRI procedure. Each patient must be screened before exposure to the MRI magnetic field.

Due to the use of the strong magnet, special precautions must be taken to perform an MRI on patients with certain implanted devices such as pacemakers or cochlear implants. The MRI technologist will need some information regarding the implanted decide, such as the make and model number, to determine if it is safe for you to have an MRI. Patients who have internal metal objects, such as surgical clips, plates, screws or wire mesh, might not be eligible for an MRI exam.

If there is a possibility that you are claustrophobic then you should ask your physician to provide you with anti-anxiety medication that you can take prior to your MRI examination. You should plan to have someone drive you home afterward.

If you are pregnant or suspect that you may be pregnant, you should notify your health care provider. To date, there is no information indicating that MRI is harmful to an unborn child, however, MRI testing during the first trimester is discouraged.

A doctor may order a contrast dye to be used during some MRI exams in order for the radiologist to better view internal tissues and blood vessels on the completed images.

If contrast is used, there is a risk for allergic reaction to the contrast. Patients who are allergic or sensitive to contrast dye or iodine should notify the radiologist or technologist.

If you have severe kidney disease or are on kidney dialysis, there is a risk of a condition called “nephrogenic systemic fibrosis” from the contrast dye. You should discuss this risk with your doctor prior to the test.

Nephrogenic Systemic Fibrosis (NSF) is a very rare but serious complication of MRI contrast use in patients with kidney disease or kidney failure. If you have a history of kidney disease, kidney failure, kidney transplant, liver disease or are on dialysis, you must inform the MRI technologist or radiologist prior to receiving contrast.

MRI contrast may have an effect on other conditions, such as allergies, asthma, anaemia, hypotension (low blood pressure), kidney disease, and sickle cell disease.

There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.

How do I prepare for an MRI?

Eat/Drink: You may eat, drink and take medications as usual for most MRI exams.  There are some specialty MRI exams that require certain restrictions. You will be provided detailed preparations instructions by Johns Hopkins Medical Imaging when you schedule your exam.

Clothing: You must completely change into a patient gown and lock up all personal belongings. A locker will be provided for you to use. Please remove all piercings and leave all jewellery and valuables at home.

What to Expect: Imaging takes place inside of a large tube-like structure, open on both ends. You must lie perfectly still for quality images. Due to the loud noise of the MRI machine, earplugs are required and will be provided.

Allergy: If you have had an allergic reaction to contrast that required medical treatment, contact your ordering physician to obtain the recommended prescription. You will likely take this by mouth 24, 12 and two hours prior to examination.

Anti-Anxiety Medication: If you require anti-anxiety medication due to claustrophobia, contact your ordering physician for a prescription. Please note that you will need some else to drive you home.

Strong Magnetic Environment: If you have metal within your body that was not disclosed prior to your appointment, your study may be delayed, rescheduled or cancelled upon your arrival until further information can be obtained.

Based on your medical condition, your health care provider may require other specific preparation.

When you call to make an appointment, it is extremely important that you inform if any of the following apply to you:

• You have a pacemaker or have had heart valves replaced
• You have any type of implantable pumps, such as an insulin pump
• You have vessel coils, filters, stents, or clips
• You are pregnant or think you might be pregnant
• You have any body piercing
• You are wearing a medication patch
• You have permanent eyeliner or tattoos
• You have ever had a bullet wound
• You have ever worked with metal (for example, a metal grinder or welder)
• You have metallic fragments anywhere in the body
• You are not able to lie down for 30 to 60 minutes.

What happens during an MRI?

MRI may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor’s practices.

Generally, MRI follows this process:

1. You will be asked to remove any clothing, jewellery, eyeglasses, hearing aids, hairpins, removable dental work, or other objects that may interfere with the procedure.
2. If you are asked to remove clothing, you will be given a gown to wear.
3. If you are to have a procedure done with contrast, an intravenous (IV) line will be started in the hand or arm for injection of the contrast dye.
4. You will lie on a scan table that slides into a large circular opening of the scanning machine. Pillows and straps may be used to prevent movement during the procedure.
5. The technologist will be in another room where the scanner controls are located. However, you will be in constant sight of the technologist through a window. Speakers inside the scanner will enable the technologist to communicate with and hear you. You will have a call button so that you can let the technologist know if you have any problems during the procedure. The technologist will be watching you at all times and will be in constant communication.
6. You will be given earplugs or a headset to wear to help block out the noise from the scanner. Some headsets may provide music for you to listen to.
7. During the scanning process, a clicking noise will sound as the magnetic field is created and pulses of radio waves are sent from the scanner.
8. It will be important for you to remain very still during the examination, as any movement could cause distortion and affect the quality of the scan.
9. At intervals, you may be instructed 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.
10. If contrast dye is used for your procedure, you may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation or a feeling of coldness, a salty or metallic taste in the mouth, a brief headache, itching, or nausea and/or vomiting. These effects usually last for a few moments.
11. You should notify the technologist if you feel any breathing difficulties, sweating, numbness, or heart palpitations.
12. Once the scan is complete, the table will slide out of the scanner and you will be assisted off the table.
13. If an IV line was inserted for contrast administration, the line will be removed.

While the MRI procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

What happens after an MRI?

You should move slowly when getting up from the scanner table to avoid any dizziness or light-headedness from lying flat for the length of the procedure.

If any sedatives were taken for the procedure, you may be required to rest until the sedatives have worn off. You will also need to avoid driving.

If contrast dye is used during your procedure, you may be monitored for a period of time for any side effects or reactions to the contrast dye, such as itching, swelling, rash, or difficulty breathing.

If you notice any pain, redness, and/or swelling at the IV site after you return home following your procedure, you should notify your physician as this could indicate an infection or another type of reaction.

Otherwise, there is no special type of care required after an MRI scan of the bones, joints, and soft tissues. You may resume your usual diet and activities unless your physician advises you differently.

Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.

Cardiac magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the structures within and around the heart. Cardiac MRI is used to detect or monitor cardiac disease and to evaluate the heart’s anatomy and function in patients with both heart disease present at birth and heart diseases that develop after birth. Cardiac MRI does not use ionizing radiation to produce images, and it may provide the best images of the heart for certain conditions.

Tell your doctor about any health problems, recent surgeries or allergies, and whether there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most orthopaedic implants pose no risk, but you should always tell the MRI technologist if you have any devices or metal in your body. Guidelines about eating and drinking before your exam vary between facilities. Unless you are told otherwise, take your regular medications as usual. Leave all jewellery at home and wear loose, comfortable clothing. You may be asked to wear a hospital gown during the exam. If you have claustrophobia or anxiety, you may want to ask your doctor for a mild sedative prior to the exam.

What is Cardiac MRI?

Magnetic resonance imaging (MRI) is a non-invasive test used to diagnose medical conditions.

MRI uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of internal body structures. MRI does not use radiation (x-rays).

Detailed MR images allow doctors to examine the body and detect disease. The images can be reviewed on a computer monitor. They may also be sent electronically, printed or copied to a CD, or uploaded to a digital cloud server.

What are some common uses of the procedure?

Cardiac MRI is performed to help your physician detect or monitor cardiac disease by:

• Evaluating the anatomy and function of the heart chambers, heart valves, size of and blood flow through major vessels, and the surrounding structures such as the pericardium (the sac that surrounds the heart).
• Diagnosing a variety of cardiovascular (heart and/or blood vessel) disorders such as tumours, infections, and inflammatory conditions.
• Evaluating the effects of coronary artery disease such as limited blood flow to the heart muscle and scarring within the heart muscle after a heart attack.
• Planning a patient’s treatment for cardiovascular disorders.
• Monitoring the progression of certain disorders over time.
• Evaluating the effects of surgical changes, especially in patients with congenital heart disease.
• Evaluating the anatomy of the heart and blood vessels in children and adults with congenital heart disease (heart disease present at birth).

How should I prepare?

You may need to wear a hospital gown. Or, you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.

Guidelines about eating and drinking before an MRI vary between specific exams and facilities. Unless you are told otherwise, take food and medications as usual.

Some MRI exams use an injection of contrast material. You may be asked if you have asthma or allergies to iodine contrast material, drugs, food, or the environment. MRI exams commonly use a contrast material called gadolinium. Gadolinium can be used in patients with iodine contrast allergy. A patient is much less likely to be allergic to gadolinium contrast than to iodine contrast. However, even if the patient has a known allergy to gadolinium, it may be possible to use it after appropriate pre-medication. For more information on allergic reactions to gadolinium contrast, please consult the ACR Manual on Contrast Media.

Tell the technologist or radiologist if you have any serious health problems or recently had surgery. Some conditions, such as severe kidney disease, may require the use of specific types of gadolinium contrast that are considered safe for patients with kidney disease. You may need a blood test to determine whether your kidneys are functioning normally.

Women should always tell their doctor and technologist if there is a chance they are pregnant. MRI has been used since the 1980s with no reports of any ill effects on pregnant women or their unborn babies. However, the baby will be in a strong magnetic field. Therefore, pregnant women should not have an MRI in the first trimester unless the benefit of the exam clearly outweighs any potential risks. Pregnant women should not receive gadolinium contrast unless absolutely necessary. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your doctor to prescribe a mild sedative prior to your exam.

Infants and young children often require sedation or anaesthesia to complete an MRI exam without moving. This depends on the child’s age, intellectual development and the type of exam. Sedation can be provided at many facilities. A specialist in paediatric sedation or anaesthesia should be available during the exam for your child’s safety. You will be told how to prepare your child.

Some facilities may have personnel who work with children to help avoid the need for sedation or anaesthesia. They prepare children by showing them a dummy MRI scanner and playing the noises they might hear during the exam. They also answer any questions and explain the procedure to relieve anxiety. Some facilities also provide goggles or headsets so the child can watch a movie while the scan is being done. This helps the child stay still and allows for good quality images.

Leave all jewellery and other accessories at home or remove them prior to the MRI scan. Metal and electronic items can interfere with the magnetic field of the MRI unit, and they are not allowed in the exam room. They may cause burns or become harmful projectiles within the MRI scanner room. These items include:

• Jewellery, watches, credit cards and hearing aids, all of which can be damaged
• Pins, hairpins, metal zippers and similar metallic items, which can distort MRI images
• Removable dental work
• Pens, pocket knives and eyeglasses
• Body piercings
• Mobile phones, electronic watches and tracking devices.

In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants may not be scanned and should not enter the MRI scanning area without first being evaluated for safety:

• Some cochlear (ear) implants
• Some types of clips used for brain aneurysms
• Some types of metal coils placed within blood vessels
• Some older cardiac defibrillators and pacemakers

Tell the technologist if you have medical or electronic devices in your body. These devices may interfere with the exam or pose a risk. Many implanted devices will have a pamphlet explaining the MRI risks for that particular device. If you have the pamphlet, bring it to the attention of the scheduler before the exam. MRI cannot be performed without confirmation and documentation of the type of implant and MRI compatibility. You should also bring any pamphlet to your exam in case the radiologist or technologist has any questions.

If there is any question, an x-ray can detect and identify any metal objects. Metal objects used in orthopaedic surgery generally pose no risk during MRI. However, a recently placed artificial joint may require the use of a different imaging exam.

Tell the technologist or radiologist about any shrapnel, bullets, or other metal that may be in your body. Foreign bodies near and especially lodged in the eyes are very important because they may move or heat up during the scan and cause blindness. Dyes used in tattoos may contain iron and could heat up during an MRI scan. This is rare. Tooth fillings, braces, eyeshadows and other cosmetics usually are not affected by the magnetic field. However, they may distort images of the facial area or brain. Tell the radiologist about them.

Anyone accompanying a patient into the exam room must also be screened for metal objects and implanted devices.

How is the procedure performed?

MRI exams may be done on an outpatient basis.

You will be positioned on the moveable exam table. Straps and bolsters may be used to help you stay still and maintain your position.

Devices that contain coils capable of sending and receiving radio waves may be placed around or next to the area of the body being scanned.

MRI exams generally include multiple runs (sequences), some of which may last several minutes.

Electrocardiogram (ECG) leads (small sticky patches) will likely be placed on your chest to help the MRI machine synchronize the image acquisition with the beating of your heart. Men may require a small area of hair to be shaved from the chest in order to ensure that the small ECG patches will stick well. A respiratory gating belt, a device that helps the computer know how you are breathing at any given time, may be placed around your upper abdomen. Additionally, a small pulse monitor may be placed on your finger.

You will be given breathing instructions and will be asked to hold your breath for short periods of time during the examination.

If a contrast material is used, a doctor, nurse or technologist will insert an intravenous catheter (IV line) into a vein in your hand or arm that will be used to inject the contrast material.

You will be placed into the magnet of the MRI unit. The technologist will perform the exam while working at a computer outside of the room.

If a contrast material is used during the exam, it will be injected into the intravenous line (IV) after an initial series of scans. More images will be taken during or following the injection.

When the exam is complete, you may be asked to wait while the radiologist checks the images in case more are needed.

Your IV line will be removed after the exam is over.

The entire examination is usually completed in less than 90 minutes once imaging has started, but may be shorter or longer depending on what the images show.

If a child has been sedated or anesthetized for an MRI exam, recovery time ranges from approximately 30 minutes to two hours after the exam is completed.

What will I experience during and after the procedure?

Most MRI exams are painless. However, some patients find it uncomfortable to remain still. Others may feel closed-in (claustrophobic) while in the MRI scanner. The scanner can be noisy. Sedation may be arranged for anxious patients, but fewer than one in 20 require it.

During cardiac MRI, your heart beat will be monitored and you will be asked to hold your breath for short periods of time while images are recorded.

It is normal for the area of your body being imaged to feel slightly warm. If it bothers you, tell the radiologist or technologist. It is important that you remain perfectly still while the images are being taken. This is typically only a few seconds to a few minutes at a time. You will know when images are being recorded because you will hear and feel loud tapping or thumping sounds. These are made when the coils that generate the radio waves are activated. You will be provided with earplugs or headphones to reduce the sounds made by the scanner. You may be able to relax between imaging sequences. However, you will be asked to keep the same position without moving as much as possible.

You will usually be alone in the exam room. However, the technologist will be able to see, hear and speak with you at all times using a two-way intercom. Many facilities allow a friend or parent to stay in the room if they have also been screened for safety.

Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help pass the time.

In some cases, IV injection of contrast material may be given before the images are obtained. The IV needle may cause you some discomfort and you may experience some bruising. There is also a very small chance of skin irritation at the site of the IV tube insertion. Some patients may have a temporary metallic taste in their mouth after the contrast injection.

If you do not require sedation, no recovery period is necessary. You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, a few patients experience side effects from the contrast material. These may include nausea, headache and pain at the site of injection. It is very rare that patients experience hives, itchy eyes or other allergic reactions to the contrast material. If you have allergic symptoms, tell the technologist. A radiologist or other doctor will be available for immediate assistance.

Who interprets the results and how do I get them?

A radiologist, a doctor trained to supervise and interpret radiology exams, will analyze the images. The radiologist will send a signed report to your primary care or referring physician, who will share the results with you.

Follow-up exams may be needed. If so, your doctor will explain why. Sometimes a follow-up exam is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. A follow-up exam may also be done to see if there has been any change in an abnormality over time. Follow-up exams are sometimes the best way to see if treatment is working or if an abnormality is stable or has changed.

What are the benefits vs. risks?

Benefits

• MRI is a non-invasive imaging technique that does not involve exposure to radiation.
• MR images of the heart are better than other imaging methods for certain conditions. This advantage makes MRI an invaluable tool in early diagnosis and evaluation of certain cardiac abnormalities, especially those involving the heart muscle.
• MRI has proven valuable in diagnosing a broad range of conditions, including cardiovascular anatomical anomalies (e.g., congenital heart defects), functional abnormalities (e.g., valve failure), tumours, and conditions related to coronary artery disease and cardiomyopathy (disease affecting the heart muscle).
• MR imaging can be used during certain interventional procedures, such as catheter-based ablation procedures to treat irregular heart rhythms, including atrial fibrillation. The use of MRI can substantially shorten the time required to perform these procedures and result in improved accuracy.
• MRI can detect abnormalities that might be obscured by bone with other imaging methods.
• The MRI gadolinium contrast material is less likely to cause an allergic reaction than the iodine-based contrast materials used for x-rays and CT scanning.
• Cardiac MRI allows for evaluation of the structures and function of the heart and major vessels without the risks of exposure to ionizing radiation which may be associated with more invasive procedures or some other non-invasive tests.

Risks

• The MRI exam poses almost no risk to the average patient when appropriate safety guidelines are followed.
• If sedation is used, there is a risk of using too much. However, your vital signs will be monitored to minimize this risk.
• The strong magnetic field is not harmful. However, it may cause implanted medical devices to malfunction or cause distortion of the images.
• Nephrogenic systemic fibrosis is a recognized, but rare, complication related to injection of gadolinium contrast. It usually occurs in patients with serious kidney disease. Your doctor will carefully assess your kidney function before considering a contrast injection.
• There is a very slight risk of an allergic reaction if contrast material is used. Such reactions are usually mild and controlled by medication. If you have an allergic reaction, a doctor will be available for immediate assistance.
• IV contrast manufacturers indicate mothers should not breastfeed their babies for 24-48 hours after contrast material is given. However, the most recent American College of Radiology (ACR) Manual on Contrast Media reports that studies show the amount of contrast absorbed by the infant during breastfeeding is extremely low. For further information please consult the ACR Manual on Contrast Media and its references.

What are the limitations of a Cardiac MRI?

High-quality images depend on your ability to remain perfectly still and follow breath-holding instructions while the images are being recorded. If you are anxious, confused or in severe pain, you may find it difficult to lie still during imaging.

A person who is very large may not fit into certain types of MRI machines. There are weight limits on the scanners.

Implants and other metallic objects can make it difficult to obtain clear images. Patient movement can have the same effect.

A very irregular heartbeat may affect the quality of images. This is because some techniques time the imaging based on the electrical activity of the heart.

The constant motion of the heart creates challenges in obtaining clear images. These challenges can be overcome by various techniques including synchronizing the imaging with ECG tracing, synchronizing the imaging with breathing, or having you perform repeated short breath holds during imaging.

An irregular heartbeat or atrial fibrillation (which makes cardiac motion and heart rate unpredictable) may cause difficulties in acquiring cardiac MR images.

MRI is generally not recommended for seriously injured patients. However, this decision is based on clinical judgment. This is because traction devices and life support equipment may distort the MR images. As a result, they must be kept away from the area to be imaged. Some trauma patients, however, may need MRI.

Although there is no reason to believe that MRI harms the foetus, pregnant women should not have an MRI exam during their first trimester unless medically necessary.

Acquiring detailed images of the coronary arteries and their branches is more difficult with MRI than with other imaging modalities. Therefore coronary artery imaging is most often done with cardiac CT or a more invasive procedure using a catheter placed into the blood vessels via the groin or arm.

MRI typically costs more and may take more time to perform than other imaging methods. Talk to your insurance provider if you have concerns about the cost of MRI

Magnetic resonance imaging (MRI) of the spine uses radio waves, a magnetic field and a computer. It creates clear, detailed pictures of the spine and surrounding tissues. MRI does not use radiation and may require an injection of gadolinium contrast material. Gadolinium is less likely to cause an allergic reaction than iodine contrast material.

Tell your doctor about any health problems, recent surgeries, allergies and whether you are pregnant. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most orthopaedic implants pose no risk. But, you should always tell the technologist if you have devices or metal in your body. Guidelines about eating and drinking before your exam vary between facilities. Unless you are told otherwise, take medications as usual. Leave jewellery at home and wear loose, comfortable clothing. You may be asked to wear a gown. If you have a fear of closed spaces, you may want to ask your doctor for a mild sedative before the exam.

Magnetic resonance imaging (MRI) is a non-invasive test used to diagnose medical conditions.

MRI uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of internal body structures. MRI does not use radiation (x-rays).

Detailed MR images allow doctors to examine the body and detect disease. The images can be reviewed on a computer monitor. They may also be sent electronically, printed or copied to a CD, or uploaded to a digital cloud server.

Currently, MRI is the most sensitive imaging test available for the spine.

What are some common uses of the procedure?

MR imaging is used to assess or detect:

• Spine anatomy and alignment.
• Birth defects in the vertebrae or spinal cord.
• Trauma injury to the bone, disc, ligament or spinal cord.
• Disc and joint disease. Both are frequent causes of severe lower back pain and sciatica (back pain radiating into lower leg).
• Compression or inflammation of spinal cord and nerves.
• Infection of the vertebrae, discs, spinal cord or its coverings (meninges).
• Tumours in the vertebrae, spinal cord, nerves or surrounding soft tissues.

Spine MRI is also used to help plan procedures such as decompression of a pinched nerve, spinal fusion, or steroid injections. The steroid injections relieve pain and are usually done using x-ray guidance. Spine MRI detects other possible causes of back pain such as compression fracture, and bone swelling. It is also used to monitor changes in the spine after an operation, such as scarring or infection.

How should I prepare?

You may need to wear a hospital gown. Or, you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.

Guidelines about eating and drinking before an MRI vary between specific exams and facilities. Unless you are told otherwise, take food and medications as usual.

Some MRI exams use an injection of contrast material. You may be asked if you have asthma or allergies to iodine contrast material, drugs, food, or the environment. MRI exams commonly use a contrast material called gadolinium. Gadolinium can be used in patients with iodine contrast allergy. A patient is much less likely to be allergic to gadolinium contrast than to iodine contrast. However, even if the patient has a known allergy to gadolinium, it may be possible to use it after appropriate pre-medication. For more information on allergic reactions to gadolinium contrast, please consult the ACR Manual on Contrast Media.

Tell the technologist or radiologist if you have any serious health problems or recently had surgery. Some conditions, such as severe kidney disease, may require the use of specific types of gadolinium contrast that are considered safe for patients with kidney disease. You may need a blood test to determine whether your kidneys are functioning normally.

Infants and young children often require sedation or anaesthesia to complete an MRI exam without moving. This depends on the child’s age, intellectual development and the type of exam. Sedation can be provided at many facilities. A specialist in paediatric sedation or anaesthesia should be available during the exam for your child’s safety. You will be told how to prepare your child.

Some facilities may have personnel who work with children to help avoid the need for sedation or anaesthesia. They prepare children by showing them a dummy MRI scanner and playing the noises they might hear during the exam. They also answer any questions and explain the procedure to relieve anxiety. Some facilities also provide goggles or headsets so the child can watch a movie while the scan is being done. This helps the child stay still and allows for good quality images.

Leave all jewellery and other accessories at home or remove them prior to the MRI scan. Metal and electronic items can interfere with the magnetic field of the MRI unit, and they are not allowed in the exam room. They may cause burns or become harmful projectiles within the MRI scanner room. These items include:

• Jewellery, watches, credit cards and hearing aids, all of which can be damaged
• Pins, hairpins, metal zippers and similar metallic items, which can distort MRI images
• Removable dental work
• Pens, pocket knives and eyeglasses
• Body piercings
• Mobile phones, electronic watches and tracking devices.

In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants may not be scanned and should not enter the MRI scanning area without first being evaluated for safety:

• Some cochlear (ear) implants
• Some types of clips used for brain aneurysms
• Some types of metal coils placed within blood vessels
• Some older cardiac defibrillators and pacemakers

Tell the technologist if you have medical or electronic devices in your body. These devices may interfere with the exam or pose a risk. Many implanted devices will have a pamphlet explaining the MRI risks for that particular device. If you have the pamphlet, bring it to the attention of the scheduler before the exam. MRI cannot be performed without confirmation and documentation of the type of implant and MRI compatibility. You should also bring any pamphlet to your exam in case the radiologist or technologist has any questions.

If there is any question, an x-ray can detect and identify any metal objects. Metal objects used in orthopaedic surgery generally pose no risk during MRI. However, a recently placed artificial joint may require the use of a different imaging exam.

Tell the technologist or radiologist about any shrapnel, bullets, or other metal that may be in your body. Foreign bodies near and especially lodged in the eyes are very important because they may move or heat up during the scan and cause blindness. Dyes used in tattoos may contain iron and could heat up during an MRI scan. This is rare. Tooth fillings, braces, eyeshadows and other cosmetics usually are not affected by the magnetic field. However, they may distort images of the facial area or brain. Tell the radiologist about them.

Anyone accompanying a patient into the exam room must also be screened for metal objects and implanted devices.

What does the equipment look like?

The traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie on a table that slides into the center of the magnet.

Some MRI units, called short-bore systems, are designed so that the magnet does not completely surround you. Some newer MRI machines have a larger diameter bore, which can be more comfortable for larger patients or those with claustrophobia. “Open” MRI units are open on the sides. They are especially helpful for examining larger patients or those with claustrophobia. Open MRI units can provide high quality images for many types of exams. Certain exams cannot be performed using open MRI. For more information, consult your radiologist.

How does the procedure work?

Unlike x-ray and computed tomography (CT) exams, MRI does not use radiation. Instead, radio waves re-align hydrogen atoms that naturally exist within the body. This does not cause any chemical changes in the tissues. As the hydrogen atoms return to their usual alignment, they emit different amounts of energy depending on the type of body tissue they are in. The scanner captures this energy and creates a picture using this information.

In most MRI units, the magnetic field is produced by passing an electric current through wire coils. Other coils are located in the machine and, in some cases, are placed around the part of the body being imaged. These coils send and receive radio waves, producing signals that are detected by the machine. The electric current does not come in contact with the patient.

A computer processes the signals and creates a series of images, each of which shows a thin slice of the body. These images can be studied from different angles by the radiologist.

MRI is able to tell the difference between diseased tissue and normal tissue better than x-ray, CT and ultrasound.

How is the procedure performed?

MRI exams may be done on an outpatient basis.

You will be positioned on the moveable exam table. Straps and bolsters may be used to help you stay still and maintain your position.

Devices that contain coils capable of sending and receiving radio waves may be placed around or next to the area of the body being scanned.

MRI exams generally include multiple runs (sequences), some of which may last several minutes.

Depending on where your symptoms are, only part of the spine may be scanned. For example, the cervical (neck) portion, the thoracic (chest) spine or the lumbar (lower) spine. Gadolinium contrast material may be used when looking for infection, tumours or recurrent disk issues after a surgery.

If a contrast material is used, a doctor, nurse or technologist will insert an intravenous catheter (IV line) into a vein in your hand or arm that will be used to inject the contrast material.

You will be placed into the magnet of the MRI unit. The technologist will perform the exam while working at a computer outside of the room.

When the exam is complete, you may be asked to wait while the radiologist checks the images in case more are needed.

Your IV line will be removed after the exam is over.

The entire exam is usually completed within 30 to 60 minutes. This will depend on whether part or all of the spine is scanned. If contrast material is used, more images will be taken after the injection. This will add another 15 to 20 minutes to the total scan time.

What will I experience during and after the procedure?

Most MRI exams are painless. However, some patients find it uncomfortable to remain still. Others may feel closed-in (claustrophobic) while in the MRI scanner. The scanner can be noisy. Sedation may be arranged for anxious patients, but fewer than one in 20 require it.

It is normal for the area of your body being imaged to feel slightly warm. If it bothers you, tell the radiologist or technologist. It is important that you remain perfectly still while the images are being taken. This is typically only a few seconds to a few minutes at a time. You will know when images are being recorded because you will hear and feel loud tapping or thumping sounds. These are made when the coils that generate the radio waves are activated. You will be provided with earplugs or headphones to reduce the sounds made by the scanner. You may be able to relax between imaging sequences. However, you will be asked to keep the same position without moving as much as possible.

You will usually be alone in the exam room. However, the technologist will be able to see, hear and speak with you at all times using a two-way intercom. Many facilities allow a friend or parent to stay in the room if they have also been screened for safety.

Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help pass the time.

In some cases, IV injection of contrast material may be given before the images are obtained. The IV needle may cause you some discomfort and you may experience some bruising. There is also a very small chance of skin irritation at the site of the IV tube insertion. Some patients may have a temporary metallic taste in their mouth after the contrast injection.

If you do not require sedation, no recovery period is necessary. You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, a few patients experience side effects from the contrast material. These may include nausea, headache and pain at the site of injection. It is very rare that patients experience hives, itchy eyes or other allergic reactions to the contrast material. If you have allergic symptoms, tell the technologist. A radiologist or other doctor will be available for immediate assistance.

Who interprets the results and how do I get them?

A radiologist, a doctor trained to supervise and interpret radiology exams, will analyze the images. The radiologist will send a signed report to your primary care or referring physician, who will share the results with you.

Follow-up exams may be needed. If so, your doctor will explain why. Sometimes a follow-up exam is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. A follow-up exam may also be done to see if there has been any change in an abnormality over time. Follow-up exams are sometimes the best way to see if treatment is working or if an abnormality is stable or has changed.

What are the benefits vs. risks?

Benefits

• MRI is a non-invasive imaging technique that does not involve exposure to radiation.
• MR images of the spine are clearer and more detailed than images obtained with other imaging methods. MRI can show spinal abnormalities, injuries and disease that may not be seen with other methods. MRI is the best available method to visualize the spinal cord and nerves.
• MRI can detect abnormalities that might be obscured by bone with other imaging methods.
• The MRI gadolinium contrast material is less likely to cause an allergic reaction than the iodine-based contrast materials used for x-rays and CT scanning.
• MRI is very useful for evaluating spinal injuries. It helps diagnose or rule out acute spinal cord compression when a physical exam shows muscle weakness or paralysis. MRI is the best available method to evaluate ligament injuries.
• MRI is able to detect subtle changes in the vertebral column that may be an early sign of infection or tumour. MRI is more sensitive than CT scanning for evaluating tumours, abscesses and other soft tissue masses near the spinal cord.
• MRI is the preferred method for assessing potential complications of surgery, including bleeding, scarring, infection and re-appearance of a herniated disk.

Risks

• The MRI exam poses almost no risk to the average patient when appropriate safety guidelines are followed.
• If sedation is used, there is a risk of using too much. However, your vital signs will be monitored to minimize this risk.
• The strong magnetic field is not harmful. However, it may cause implanted medical devices to malfunction or cause distortion of the images.
• Nephrogenic systemic fibrosis is a recognized, but rare, complication related to injection of gadolinium contrast. It usually occurs in patients with serious kidney disease. Your doctor will carefully assess your kidney function before considering a contrast injection.
• There is a very slight risk of an allergic reaction if contrast material is used. Such reactions are usually mild and controlled by medication. If you have an allergic reaction, a doctor will be available for immediate assistance.

What are the limitations of MRI of the Spine?

• High-quality images depend on your ability to remain perfectly still and follow breath-holding instructions while the images are being recorded. If you are anxious, confused or in severe pain, you may find it difficult to lie still during imaging.
• A person who is very large may not fit into certain types of MRI machines. There are weight limits on the scanners.
• Implants and other metallic objects can make it difficult to obtain clear images. Patient movement can have the same effect.
• A very irregular heartbeat may affect the quality of images. This is because some techniques time the imaging based on the electrical activity of the heart.
• MRI is generally not recommended for seriously injured patients. However, this decision is based on clinical judgment. This is because traction devices and life support equipment may distort the MR images. As a result, they must be kept away from the area to be imaged. Some trauma patients, however, may need MRI.
• Although there is no reason to believe that MRI harms the foetus, pregnant women should not have an MRI exam during their first trimester unless medically necessary.
• MRI typically costs more and may take more time to perform than other imaging methods. Talk to your insurance provider if you have concerns about the cost of MRI.
• In some patients, vertebral fractures may be better detected by CT scan.