You may have clear liquids only (jello, tea, fruit drinks without pulp, black coffee, water, etc.) for 6 hours before the exam.
It's important not to drink a lot of caffeine before your MRI because caffeine will make your blood vessels constrict. If your scan is monitoring blood flow, constricted blood vessels will give you inaccurate results.
This high incidence of use is significant because caffeine can affect the results of several common diagnostic tests, including MRI.
No other preparation is required, except for the cardiac stress perfusion MRI where you will be asked to avoid caffeine for 24–48 hours before the test. Caffeine interferes with the action of adenosine (see Stress Perfusion MRI above), which is used to simulate the stress part of this MRI scan.
Since the MRI machines are magnets, it is best to not apply deodorants, antiperspirants, perfumes, or body lotions before the examination. These items contain metals that might interfere with the magnetic field inside the MRI machine and cause you to have distorted images and wrong results.
You will not be able to have breakfast the morning of your surgery. You can brush your teeth in the morning, just be sure to spit the water out!
On the day of your MRI scan, you should be able to eat, drink and take any medication as usual, unless you're advised otherwise. In some cases, you may be asked not to eat or drink anything for up to 4 hours before the scan, and sometimes you may be asked to drink a fairly large amount of water beforehand.
If You Have an Overactive Bladder
This feeling of urgency can make it harder to hold urine in. While you may still experience this urgency to a degree, not drinking for several hours before your procedure can make you less likely to experience incontinence during the scan.
If you're getting an MRI/MRA with IV Contrast
For IV Contrast patients, you should stay hydrated and should drink 16 oz. of water prior to your exam and 16 oz. of water after your exam.
The level of caffeine in your blood peaks about one hour later and stays at this level for several hours for most people. Six hours after caffeine is consumed, half of it is still in your body. It can take up to 10 hours to completely clear caffeine from your bloodstream.
Radiologists recommend fasting prior to undergoing a CT or MRI with contrast because of the possible side effects of the contrast agents. While rare, side effects of contrast can cause nausea or vomiting during the test.
Keep your eyes closed or even wear a blindfold.
It's much easier in an open MRI it's wider than a standard scanner, so patients shouldn't feel any walls touching them.
Preparing for a CT scan
Usually, you will be asked to not eat for two hours before your appointment time and to drink 500ml of water (tea or coffee is fine) during this time.
Exam preparation:
Patient should not eat or drink anything for eight hours before MRI scan.
It's important that patients remove all clothing prior to their MRI exam. We ask patients to remove: All outer clothing, including shoes. Bras or any undergarment that could have metal in it.
Unless you're told otherwise, you can shower and wash your hair the morning of your MRI. Don't use any hair products (such as hair spray or hair gel). Don't wear any metal objects. Remove all jewelry, including body piercings.
How long does an MRI scan take? A single scan may take a few seconds or 3 to 8 minutes. You may be asked to hold your breath during short scans. The total scan lasts 15 to 90 minutes, depending on the size of the area being scanned and how many images are needed.
Conclusion. We demonstrate that within a range of physiologic conditions commonly encountered in routine clinical scans (no pretreatment with hydration, well hydrated before MRI, and overnight fasting), brain TWC and brain volumes are not substantially affected in a healthy control cohort. J. Magn.
You won't have pain from the magnetic field or radio waves used for the MRI test. But you may be tired or sore from lying in one position for a long time. If a contrast material is used, you may feel some coolness when it is put into your IV.
A pelvic or abdominal MRI scan requires fasting (no food & water consumption) for a minimum of 5 hours before the scan to ensure accurate test results. In most other MRI scans, no fasting is necessary.
Most metal tooth fillings or other permanent dental implants won't cause a problem. If you have detachable metal braces or a retainer, you should take them out before you get an MRI.
You may take all medicines. You may eat and drink unless you are having an MRCP, a specific exam for your gallbladder. You will be asked to fill out a patient history form before your exam. A non‐iodine contrast medication may be injected into your vein through an IV line to make a better, clearer picture.
Drawbacks of MRI scans include their much higher cost, and patient discomfort with the procedure. The MRI scanner subjects the patient to such powerful electromagnets that the scan room must be shielded.