What is an MRI?
An MRI is a noninvasive imaging technique that utilizes a powerful magnetic field, radio waves, and a computer to create detailed images of your body’s internal structures. MRIs are most often used when diagnosing a condition requires a clearer picture of internal organs and soft tissue, as well as other internal structures within the body.
What shows up on an MRI?
Almost everything shows up on an MRI. Your body is mostly made of water and the hydrogen atoms in H2O are magnetic. So, in essence, an MRI machine measures the water content in your soft tissue, like the brain, nerves, muscles and organs.
Your body tissue shows up in varying degrees of light and dark — depending on the fat and water content — which a radiologist can examine to see if your tissue is healthy. Air and hard bone don’t send out MRI signals, so they appear black on the image. But even in those black areas, radiologists can determine whether everything looks normal.
MR angiogram (MRA) can be used to view arteries and veins. A standard MRI can’t see fluid that is moving, such as blood in an artery, and this creates “flow voids” that appear as black holes on the image. Contrast dye (gadolinium) injected into the bloodstream helps the computer “see” the arteries and veins. Contrast is also used to view tumors and arteriovenous malformations (AVMs).
What conditions does an MRI help diagnose?
An MRI scan can be used to help diagnose a wide variety of ailments and conditions. Due to the nature of the images resulting from scans, some of the most commonly diagnosed conditions include:
- Tumors
- Diseases of the abdominal and pelvic organs
- Disorders of bones, joints and soft tissues
- Evaluation the brain and spine
- Breast imaging in high-risk individuals
How should I prepare for an MRI?
Unless directed otherwise by your doctor, you should continue eating and taking any medications as normal, however it is recommended to avoid caffeinated beverages prior to the test.
Other items you will be asked to do:
- Wear no jewelry or other metal objects the day of the procedure.
- Please be sure to arrive 30 minutes prior to your MRI appointment.
- Bring any relevant information regarding implants.
Your healthcare team will guide you through any other necessary preparations to ensure you have a safe and successful scan.
Note: you may be expected to change into a gown or scrubs at the time of your appointment for safety reasons, some clothing items may contain material not suitable for an MRI.
Many of the following items are contraindications to having an MRI as they are not compatible with the magnetic field present around all MRI machines. If you have any of the items listed below, please let us know so we can make arrangements for you before your appointment.
- Cardiac Pacemaker
- Artificial heart valve prostheses
- Aneurysm clips
- Eye implants or metal ear implants or any metal implants activated electronically, magnetically or mechanically
- Copper 7 IUD
- Shrapnel or non-removed bullet
- Pregnancy
- Weight over 350 lbs
- Claustrophobia
- Any metal puncture(s) or fragment(s) in eye
What should I expect during an MRI?
Your MRI experience will differ depending on the type of MRI you’re receiving and its purpose. The scan will typically take 20-50 minutes. In all cases you will be asked to remain as still as possible for the duration of your scan. This ensures the technician can get a clear, detailed image, which is necessary for proper analysis and diagnosis. Rest assured that your doctors will discuss the procedure with you in depth before you begin.
During your scan, you’re only lying down on a table. The table just happens to move inside a large magnet! Some MRI machines are open to accommodate larger patients and those with claustrophobia. The machine’s coils can be a little noisy. They’re switched on and off rapidly during the scan, and the sounds can range from a light tapping to a loud knocking or thumping. You can also get earplugs to help reduce the machine’s noise or listen to music on the stereo system throughout your test.
What happens after an MRI?
After your MRI procedure, the images are reviewed by a trained radiologist. They interpret the images to diagnose any abnormalities or conditions. Your doctor will then discuss the results with you and recommend any necessary follow-up actions or treatments based on the findings.