Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to produce cross-sectional images of organs and internal structures in the body. Each cross-section represents a “slice” of the part of the body being imaged. When viewed together, these images provide a view that has greater clarity and more detail than X-ray images.
An MRI system includes a scanner shaped like a donut and a motorized table that slides in and out of the opening. The magnetic strength of the scanner is measured in teslas, with 3 tesla (3T) scanners providing the highest resolution images. For some exams, a lower resolution is more appropriate. Columbia Radiology offers state-of-the-art MRI, including:
- 3T and 1.5T scanners
- Wide bore technology (wider and shorter opening) for added comfort
- Multiple locations
- Subspecialized radiologists from Columbia read all exams
How MRI is Used by Doctors
Doctors use MRI to diagnose brain and nervous system disorders; problems affecting tendons, cartilage, ligaments, and bone marrow; inflammatory bowel disease and other gastrointestinal disease; and heart problems, such as congenital heart disease. MRI is also used to diagnose cancer and monitor response to treatments for cancer and other conditions.
A form of MRI called magnetic resonance angiography (MRA) is an MRI that focuses on blood vessels and blood flow. MRA is most commonly used to identify aneurysms and blockages of blood vessels in the head, neck, chest, abdomen, or extremities.
How do I prepare for the test?
On the day of the test you should wear comfortable clothes, and we may ask you to change into a gown when you arrive at the exam site. Do not wear eye makeup and leave metallic accessories like jewelry and watches at home.
For some MRI exams we will give intravenous contrast ("dye") to help doctors see normal and abnormal anatomical details. If you will be sedated or receive a contrast material for the MRI, we will give you more specific instructions when you schedule the exam.
Please let us know about allergies you may have to contrast agents.
What will happen during the test?
If your doctor has requested that you have an MRI with contrast, we will first insert an IV, usually into your arm.
We will then take you to the MRI exam room and position you on the MRI table, with your head on a pillow or in a padded plastic cradle. Usually you will lie on your back, although for some scans you may have to lie on your stomach or side. Once you are positioned, the table will slide into the scanner, and a red light may shine on your body momentarily to ensure that you are properly positioned. MRI scanners make buzzing and clicking sounds, so we will give you ear plugs to make you more comfortable.
The MRI technologist will leave the room to perform the scan, but he/she will be able to see, hear, and speak with you at all times. You may be asked to hold your breath for short periods of time. It's important to lie still and relax so that we can record clear images.
The MRI scan can take from 15 minutes to one hour. Most exams take between 20 to 30 minutes.
Are there any risks?
MRI does not use ionizing radiation, the type of radiation used in X-rays and CT scans, and there are no known harmful side effects associated with temporary exposure to the magnetic field used by MRI scanners. There is a slight risk that you will develop an allergic reaction to the contrast agent.
After the test
After the exam you can immediately resume your normal activities. A radiologist will analyze the MRI images and will share the results with the doctor who requested the exam. Your doctor will then discuss the results with you.