MRIs, or magnetic resonance imaging, can be done with or without contrast.
An MRI with contrast is performed in a hospital or outpatient facility. During the procedure, a healthcare provider will inject the contrast material into a vein in your arm, then place you in an MRI machine for the scan.
This article explains how MRI with contrast works as well as the different dyes a radiologist may use. It also describes the potential risks and what to expect if you need to undergo this common procedure.
What Is the Purpose of an MRI With Contrast?
An MRI with contrast can make it easier to see the condition of your organs and blood vessels during an MRI scan. It isn’t a good choice for every situation, however. The decision to use contrast is based on whether the aim of the procedure is:
Diagnostic (to identify disease)Interventional (to aid with the management of a known condition)
Their use is directed in part by the American College of Radiology (ACR) Appropriateness Criteria.
The list of conditions in which contrast may or may not be useful is extensive. They are broadly outlined by the ACR in the following chart.
Types of Contrast Agents
Most of the contrast agents used contain a rare metal called gadolinium that interacts with the magnetic field created by the MRI machine. Gadolinium-based contrast agents (GBCAs) come in several types that are differentiated by:
Chemical compositionMagnetic propertiesHow they’re dispersed through the bodyHow they’re administered
Some GBCAs are organ-specific, while others have a heavier molecular weight so they remain within the circulatory system and don’t diffuse into adjacent tissues. Others still can target specific cells like tumors.
A GBCA isn’t always useful. For example, gadolinium can’t readily cross the blood-brain barrier (BBB) that protects the brain from harmful substances. While helpful in diagnosing diseases with a compromised BBB, like multiple sclerosis, GBCAs aren’t as useful if the barrier is intact.
MRI contrast agents approved for use by the U.S. Food and Drug Administration (FDA) include:
Dotarem (gadoterate meglumine)Evoist (gadoxetate disodium)Gadavist (gadobutrol)Magnevist (gadopentetate dimeglumine)Multihance (gadobenate dimeglumine)Omniscan (gadodiamide)OptiMARK (gadoversetamide)Prohance (gadoteridol)
Before the Test
An MRI study is performed by a radiology technician (also known as a radiographer or radiology technologist) and interpreted by a radiologist.
Timing
An MRI scan with contrast can take anywhere from 30 minutes to 90 minutes, depending on the area of the body being scanned, the agent used, and the GBCA’S route of administration.
MRIs using oral GBCAs may take up to two and a half hours, requiring you to drink multiple doses and wait until the agent passes into the intestine.
Be sure to arrive 15 to 30 minutes before your appointment to fill out the necessary paperwork and settle in.
Location
MRIs are performed in outpatient MRI clinics and in hospitals.
The MRI machine will be situated in its own room within the facility. After placing you inside the machine, the radiology technician will operate the unit from behind a glass partition. You’re able to communicate via a two-way speaker system inside the unit.
The MRI machine itself is a tube-like device into which a flatbed is inserted and removed via remote control. Some smaller units allow you to insert just an arm or leg.
Many newer models are open on the sides, reducing the claustrophobia that some people feel when being scanned.
What to Wear
Because MRI utilizes strong magnetic fields, you will not be allowed to wear anything that contains metal during the procedure, including:
ZippersBucklesMetal buttonsUnderwire bras
It’s best to leave jewelry at home and to remove metal accessories from the body, such as piercings and hairpieces.
You’ll be given a gown to change into if your clothing interferes with the MRI readings. Some people come with their own clothes, such as drawstring pants, sweatpants, plain T-shirts, or workout wear. To avoid walking on bare feet, bring along socks or a pair of slippers.
Dentures and hearing aids should be removed prior to the procedure. Medical staff will provide you with a secure place to store your belongings.
Food and Drink
For GBCAs delivered by injection or IV, you can usually eat, drink, and take medications as you normally would. The same does not apply to oral GBCAs, which may require you to stop eating and drinking four or more hours in advance.
The radiology staff will advise you if any dietary or medication restrictions apply to your procedure.
Cost and Health Insurance
MRIs with contrast can cost anywhere from $300 to $3,000, depending on the body part being scanned and your location.
Many insurance companies will cover at least a portion of the cost but require prior authorization to ensure that it is medically necessary.
The extent of coverage can vary by the insurance plan, so check on copay or coinsurance costs in advance of the procedure and confirm that the radiology unit and radiologist are both in-network providers.
What to Bring
Be sure to bring your photo ID and insurance card with you as well as an approved form of payment for any copay/coinsurance costs. If you plan to wear any small jewelry there, you may want to bring a pouch for safekeeping.
Other Considerations
Let the radiology staff know in advance if you have:
A metal implantPacemakerDrug infusion pumpArtificial limbs or jointsTattoos containing metal ink
While many of these are MRI-safe, they can potentially interfere with the reading.
Tell the staff if you’re pregnant.
If you have claustrophobia, let the staff know well in advance. In some cases, you might be able to take a light sedative. If one is used, you’ll need to arrange for someone to drive you home after the procedure.
How an MRI With Contrast Is Performed
For an MRI with contrast, you’ll be working with a technician certified in the administration of intravenous, oral, and intra-articular GBCAs.
Qualified technicians are also allowed to administer sedation, although a nurse may also be on hand to do so.
Pre-Test
After filling out the necessary paperwork and signing a consent form, you will be led to a changing room to change into a hospital gown (if needed).
Prior to the MRI, the technician or nurse will check your weight, height, heart rate, temperature, and blood pressure. The technician will then prepare you for the scan in one of several ways.
Intravenous
If the GBCA is intravenous, an IV catheter will be placed in a vein (usually in your arm).
You may feel a sharp poke and a momentary cold sensation as the GBCA is delivered, but you should otherwise feel little pain. If it hurts, let the technician know.
A sedative can also be administered through a portal in the catheter if needed.
Oral
If the GBCA is oral, you’ll be given one or several doses of the agent to drink. Some are berry-flavored, while others have a sweet, syrupy taste.
Some people develop a metallic taste in their mouth or feel the need to go to the bathroom after drinking the solution. This is normal. However, if you feel nauseated or have stomach pain, let the technician know immediately.
Intra-articular
If the GBCA is delivered intra-articularly, the radiologist may use a topical numbing agent prior to delivering the injection. In some cases, excess joint fluid may need to be removed via arthrocentesis.
During the injection, you may feel pressure or pain along the injection route along with a momentary cold sensation. The injection usually takes around 30 seconds to a minute.
Throughout the Test
After the GBCA is delivered, you’ll be led to the flatbed of the MRI machine and strapped in to prevent movement.
For MRIs of the head, a cage-like head brace may be used. Depending on the level of sedation used, breathing, heart rate, blood oxygen, and blood pressure may be tracked during the procedure, especially in children.
You may also be given a pair of noise-reducing headphones through which you can communicate with the technician.
It is not uncommon to feel a little warmth during the scan. You will also need to be prepared to experience a loud noise, which some describe as locomotive-like, as each image is taken. Newer machines are far quieter, however.
If you are unable to hold a position, are cramping, or suddenly feel nauseated, let the technician know. It is not a problem to stop and rest until you are ready to proceed.
Once the technician has completed the requested scans, the images will be reviewed to ensure that all are clear and correctly positioned. In some cases, a part of the scan may need to be repeated.
Post-Test
If a sedative was not used, you can usually dress and leave immediately. The technician or nurse may want to check that you have no ill effects before you are allowed to go.
If a sedative was used, you will be taken to a recovery room and monitored until you are able to sit up steadily. Once you are able to stand, someone will need to drive you home. Ideally, that person will stay with you for 24 hours in the event of an unexpected side effect.
After the Test
In most cases, there will be no immediate or lasting effects from an MRI with contrast. Still, it is important to call your healthcare provider immediately if you have any unusual or severe symptoms, including:
Abnormal heartbeatShortness of breathSevere pain, redness, swelling, or discharge at an injection site
Interpreting Results
MRI with contrast scans are interpreted by a radiologist who will review the findings in context with previous scans and your available medical history. They’ll then issue a radiology report within a few days, which your healthcare provider will review with you.
A typical radiology report includes a copy of each individual scan along with notations of any abnormalities seen. Typically, each image will be broadly classified as either:
NormalAbnormalInconclusive
Specific details will be listed in the impressions section of the report, which your healthcare provider can explain to you.
Based on an evaluation of the scans and a review of your medical history, the radiologist may offer a specific diagnosis or a list of possible causes in a differential diagnosis.
Follow-Up
If findings are abnormal or potentially abnormal, you may be sent for additional imaging tests or procedures to either confirm the diagnosis or determine the severity of the condition.
For example, a growth suspected of being cancerous may require a positron emission tomography (PET) scan, which can identify malignancies based on changes in metabolism, or a biopsy, in which a tissue sample is obtained for examination by a pathologist.
If a finding is inconclusive, the MRI may be repeated or an alternative method of imaging may be used. For example, CT scans are often better at imaging bone disorders than MRIs, which are better able to image soft tissues.
Risks and Contraindications
GBCAs are generally considered safe with relatively few side effects. If side effects do occur, they tend to be transient and resolve on their own without treatment. In rare instances, certain groups of people, including those with kidney dysfunction, may experience severe side effects or complications.
The long-term, cumulative effects of GBCAs are unknown. Due to this, your healthcare provider may limit the number of MRIs with contrast you receive or interspersed MRIs with other imaging techniques, such as X-rays or computed tomography (CT) scans.
Intravenous Side Effects
GBCAs are most commonly delivered by an intravenous (IV) infusion into a vein. The most common side effects of GBCA infusions are:
A cold sensation during the injectionHeadacheNauseaDizzinessCoughVomitingRapid heartbeatShortness of breath
Although rare, some people may experience a mild allergic reaction to gadolinium. The main symptom is itchy skin, and the allergy itself is rarely severe.
Oral Side Effects
Oral GBCAs are sometimes used for MRI scans of the gastrointestinal tract. You swallow them in liquid form before the scan. The contrast agent typically involves a form of gadolinium (called gadolinium-DPTA) mixed with mannitol (a type of sugar alcohol that is poorly absorbed by the intestines).
Mannitol is known to cause nausea, vomiting, and diarrhea in some people. While gadolinium can be used on its own with few, if any, gastrointestinal side effects, it needs mannitol to remain stable in the acidic environment of the stomach and intestine.
Intra-articular Side Effects
Arthrography is an MRI technique used to image joints if a standard MRI does not provide enough detail. Arthrography requires an intra-articular injection of GBCA into the joint space.
The injection itself can cause localized pressure and pain. Some mild swelling may also occur after the procedure, which can usually be treated with ice application. There may also be redness and bruising at the injection site.
Rare Side Effects
On rare occasions, certain GBCAs have been known to cause a serious condition called nephrogenic systemic fibrosis (NSF) in people with severe kidney disease.
NSF can cause tightening and hardening of the skin similar to scleroderma, as well as the contraction of tendons and muscles, impairing movement and joint mobility. The function of certain organs, such as the heart, lung, diaphragm, stomach, intestines, or liver, may also be impaired.
NSF has no cure, and no treatment is known to deliver consistent results. For this reason, GBCAs should be used with extreme caution in people with reduced kidney function and avoided in anyone with severe chronic kidney disease, acute kidney injury, or on dialysis.
Long Term Safety
The discussion about the long-term safety of GBCAs is ongoing, particularly when they’re used extensively or on a regular basis (such as when monitoring multiple sclerosis).
In 2015, the FDA issued a safety announcement citing studies in which the prolonged use of gadolinium in people with MS resulted in deposits of the material in brain tissues.
More recent research suggests that the risk of accumulation is dose-dependent, meaning the longer gadolinium is used, the greater the risk. For people exposed to GBCAs only once or several times, the risk appears to be negligible.
What the FDA advisement failed to say is whether the deposits pose any health risks. Though some scientists have suggested that the accumulations may cause neurotoxicity (poisoning of the brain), there has been little evidence of this.
Despite the conclusions, the researchers would not go so far as to say that the buildup of gadolinium would never cause problems. Rather, they suggested that further research is needed before gadolinium can be empirically regarded as safe.
A Word From Verywell
If a healthcare provider recommends a contrast-enhanced MRI, it is not unreasonable to ask if the contrast agent is really necessary. There may be reasons why contrast is needed, but it’s fair to ask if there are other options.
This is especially true if you have known kidney disease or have undergone multiple MRIs with contrast. If in doubt, don’t hesitate to seek a second opinion.
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