Quick Answers
The general guideline is to avoid food and drink for 4-6 hours before an MRI with contrast. However, the exact fasting time may vary depending on the exam. Here are some quick answers:
- For MRI abdomen/pelvis with contrast: Do not eat for 4-6 hours before the exam.
- For MRI enterography: Follow instructions from your doctor, but often need extended fast of 8-12 hours.
- For cardiac MRI with contrast: Fast for 2-4 hours prior.
- For MRI brain with contrast: Most facilities allow a light meal up to 4 hours before.
- For MRA head and neck: Fast for 2-4 hours beforehand.
The most important thing is to follow the guidelines provided by your doctor and imaging facility. Tell your provider about any food allergies or other conditions that may affect your prep instructions. Pay close attention to what you can and cannot consume before your specific MRI exam with contrast.
Why Fasting is Required Before an MRI with Contrast
Most MRI exams with intravenous (IV) contrast require some period of fasting leading up to the procedure. This fasting helps avoid side effects and improves the quality of the images.
There are two main reasons fasting is recommended before an MRI with contrast:
- Reduce side effects: IV contrast agents can sometimes cause nausea or vomiting. Eating food before the exam increases the chances of these side effects occurring. Fasting helps reduce nausea that may be caused by the contrast material entering an empty versus full stomach.
- Improve image quality: Any food particles remaining in the gastrointestinal tract can alter or degrade the images taken during an MRI with contrast. Fasting helps clear food from the GI system so the images of these organs are clearer.
Role of Gastrointestinal Contrast
For MRI studies of the abdomen and pelvis, oral contrast is often given in addition to IV contrast. This helps improve visualization of the gastrointestinal tract. The radiologist can then better distinguish the intestinal organs from other soft tissues in the images.
Oral contrast usually consists of a special solution you drink before the exam. Because it coats the inside of your GI tract, eating food too soon before the MRI can disrupt the contrast coating and reduce the quality of images.
General Timeline for Fasting Before an MRI with Contrast
The typical fasting period required before common MRI exams with contrast include:
- MRI abdomen and pelvis: Do not eat for 4-6 hours beforehand.
- MRI enterography: Requires extended fast of 8-12 hours.
- Cardiac MRI: Hold food intake for 2-4 hours prior.
- MRI brain: Most facilities allow light meal up to 4 hours before exam.
- MRA head and neck: Fast for 2-4 hours before procedure.
However, these are just general guidelines. The exact fasting instructions can vary between healthcare facilities. And different types of MRI exams may require longer or shorter prep times.
Key Tips
- Always follow the specific guidelines provided by your doctor and imaging center.
- Ask your provider if you have any questions about what you can eat/drink before the MRI.
- Be sure to mention any food allergies or health conditions that may affect your ability to fast.
- Pay attention to instructions about oral contrast or other bowel prep if needed.
- Do not sneak any snacks, gum, candy, etc. This could affect your images or cause side effects.
Detailed Fasting Instructions Based on MRI Exam
The necessary fasting period can range from 2-12+ hours depending on the type of MRI with contrast you are having. Here is more detail on prep for specific exams:
MRI Abdomen and Pelvis with Contrast
For an MRI of the abdominal and pelvic organs, you will typically be instructed to avoid all food and drink for 4-6 hours beforehand. This allows your stomach and GI system to empty.
You may be given oral contrast to drink before the exam. Follow all instructions about when to start drinking the contrast solution and how much to consume.
Let your provider know if you have any food allergies, swallowing problems, or conditions like gastroparesis that could impact your ability to digest the oral contrast.
MRI Enterography
MRI enterography provides detailed images of the small intestine. It requires more extensive preparation to optimize the images.
You will need to follow bowel prep instructions from your provider. This typically involves:
- Drinking only clear liquids starting the evening before the exam.
- Avoiding all solid foods for 8-12 hours prior.
- Taking a laxative or enema to cleanse the bowels.
- Drinking oral contrast solution over a set timeframe before the test.
Follow all enterography prep guidelines carefully for the best results. Inform your provider if any aspect of the bowel preparation is problematic for you.
Cardiac MRI with Contrast
For an MRI to examine the heart and vessels, fasting for 2-4 hours before the procedure is typically adequate.
You may be instructed to avoid caffeine and nicotine before the cardiac MRI as well. Drink only water during the fasting period leading up to your appointment time.
MRI Brain with Contrast
For imaging of the brain, many facilities allow patients to have a light meal up to 4 hours prior to the MRI scan.
A light meal may include:
- Plain toast or crackers
- Fruit juice without pulp
- Clear liquids like water, black coffee/tea, carbonated beverages
Avoid solid foods, milk products, and thick drinks within the 4 hours pre-MRI. Check with your provider about any fasting guidelines for medications you take.
MRA Head and Neck
When imaging the cerebral arteries and veins or carotid arteries, fasting for 2-4 hours pre-procedure is common.
You may be allowed limited clear liquids during this brief fast. Avoid any thick, heavy, or fatty foods which could degrade the image quality.
If you are also having an MRI brain, follow the fasting instructions for that exam which may be less restrictive.
What You Can Eat and Drink Before an MRI with Contrast
During the fasting period leading up to your exam, restrictions depend on the type of MRI you are having. Here are some general guidelines on what may be allowed:
- Water: Clear, non-carbonated water is almost always ok.
- Clear sodas/juices: Clear soft drinks, juices without pulp, etc. are usually permitted in moderation.
- Plain coffee/tea: Black coffee or tea with no milk/creamer may be approved.
- Broth: Clear broths without solid pieces may be allowed.
- Gelatin: Plain gelatin desserts are sometimes ok.
- Popsicles: Flavored ice pops can help with hunger and thirst.
Avoid any products containing milk, pulp, seeds, fiber, fat, or protein which could leave residue in your GI tract. Check with your provider if unsure about a particular food or drink.
Tips to Make Fasting Easier
- Stay well-hydrated with approved clear fluids.
- Avoid caffeinated and carbonated drinks which can cause dehydration.
- Suck on hard candies to help distract from hunger.
- Chew sugar-free gum to promote saliva production.
- Try to schedule exam for early morning when you are less hungry.
- Rest and avoid strenuous activities that can make you more aware of hunger.
What You Cannot Eat or Drink Before an MRI with Contrast
Certain foods and beverages should always be avoided in the hours leading up to your MRI scan with contrast. Restricted items include:
- Solid foods of any kind.
- Dairy products – milk, yogurt, cheese, ice cream, etc.
- Nuts, seeds, granola, popcorn, crackers with seeds.
- Fibrous fruits and vegetables – oranges, apples, celery, broccoli, etc.
- Oils, butter, fatty and fried foods.
- Thick, pulpy juices.
- Alcohol.
- Caffeine.
- Herbal supplements.
Also avoid any liquids colored red, purple, green, or dark blue, which can affect MRI image quality. Do not chew gum or eat candy/mints during the fasting period.
If you have a medical condition that requires you to eat or drink specific items at certain times, discuss this with your provider managing the MRI prep.
Reasons to Strictly Follow Fasting Guidelines
It is critical to carefully follow all fasting instructions before an MRI with contrast for several reasons:
- Avoid side effects like nausea or vomiting from contrast material.
- Prevent delays or cancellation if you are unable to complete the exam due to sickness.
- Get the clearest images free of artifacts from gastrointestinal contents.
- Decreased need to repeat MRI sequences or possibly reschedule exam if prep was inadequate.
Non-compliance with fasting or bowel prep requirements can seriously impact the accuracy and effectiveness of your MRI scan.
What to Expect After an MRI with Contrast
Oral contrast agents are designed to pass through your system quickly. Intravenous contrast also clears within a short timeframe. So you can generally expect to be able to eat and drink normally soon after your MRI exam is completed.
Here is what to expect and when you can resume your regular diet:
- Immediately after: Most facilities provide water or juice once the MRI is finished to help you rehydrate. Take anti-nausea meds if prescribed.
- 30 minutes to 2 hours after: Consume light snacks like saltine crackers, broth, or gelatin if you are feeling up to it.
- 2 hours after: Drink clear fluids to help flush any remaining contrast and hydrated. Try juice, soda, popsicles, etc.
- 4-6 hours after: Return to a normal diet as tolerated with plenty of water. Start with bland foods that are easy to digest.
Some patients report feeling minor side effects like headache or nausea for 12-24 hours after the MRI with contrast. Call your doctor if symptoms persist or worsen.
Tips for Eating After MRI with Contrast
- Begin with easily digested foods – broth, crackers, apple sauce, white rice, etc.
- Avoid spicy, greasy, fried, or gas-producing items at first.
- Stay well-hydrated by sipping water constantly.
- Take anti-nausea medications as prescribed if needed.
- Rest and take it easy until any side effects resolve.
- Consider a bland BRAT diet – bananas, rice, applesauce, toast.
Most patients can return to a normal diet within 6-8 hours after the MRI contrast administration as long as they do not experience severe side effects requiring longer dietary restrictions.
Special Considerations
Certain conditions may require advance preparation or special instructions for fasting before an MRI with contrast. Be sure to discuss any relevant factors with your doctor.
Bowel Issues
Let your provider know about any bowel problems like:
- Inflammatory bowel disease (IBD)
- Irritable bowel syndrome (IBS)
- Diverticulitis
- Constipation or diarrhea
- Bowel obstruction
- Colostomy or ileostomy
Modifications to the standard prep may be needed. You may also be given additional laxatives or enemas to help adequately clear your bowels.
Diabetes
Inform your provider if you have diabetes requiring insulin or other medications. Your normal dosage and timing schedule may need adjusted for optimal blood sugar control while fasting.
Bring glucose tablets or candy in case you experience low blood sugar symptoms during the MRI.
Medications
Discuss all medications and supplements you take with your provider. You may need to adjust the timing of certain doses before the MRI.
For example, oral diabetes medicine or antibiotics may need taken at a different time than normal when fasting.
Allergies to Contrast
If you have a prior contrast allergy or sensitivity, the radiologist may prescribe a steroid medication to take in advance of the MRI exam.
Let your provider know about any history of reaction to gadolinium, iodine, or shellfish allergies which could indicate higher risk.
Kidney Problems
Impaired kidney function can increase the risk of a rare but serious complication called nephrogenic systemic fibrosis (NSF) from gadolinium-based contrast agents used in MRI exams. Be sure your provider knows your latest glomerular filtration rate (eGFR) and information about any kidney diseases like:
- Acute kidney injury
- Chronic kidney disease
- Dialysis treatment
- Single kidney
- Kidney transplant
Your doctor may choose an alternative imaging exam if your kidney function is significantly decreased.
| Type of MRI Exam | Recommended Fasting Period |
|---|---|
| MRI abdomen/pelvis with contrast | 4-6 hours |
| MRI enterography | 8-12 hours |
| Cardiac MRI with contrast | 2-4 hours |
| MRI brain with contrast | Light meal up to 4 hours before |
| MRA head and neck | 2-4 hours |
Conclusion
Fasting for a period before an MRI exam with contrast allows the gastrointestinal tract to empty and leads to clearer images free of food material artifacts. This also reduces the chances of nausea or other adverse reactions to the contrast agent.
Follow all prep guidelines provided by your doctor and MRI facility. The fasting time required varies based on the body part being studied but commonly ranges from 2-12 hours for most MRI procedures with contrast.
Drink only clear liquids during the fasting window. Avoid all solid foods, dairy products, and anything with fat, fiber or protein. Speak with your provider if you have any medical conditions that may affect your ability to follow the necessary fasting instructions.
