Magnetic resonance imaging (MRI) is a medical imaging device that uses strong magnetic fields, radio waves, and a computer to produce detailed images of the organs and tissues within the body. An MRI scan does not use ionizing radiation, unlike X-rays and computed tomography (CT).
What is ionizing radiation?
Ionizing radiation activity can alter molecules inside the cells of our bodies. It can also lead to tissue or skin damage.
How does an MRI scan machine work?
The MRI scan machine consists of a large tube with a table in the middle, allowing the patient to slide in during the scan. The scanner contains powerful magnets that release radio waves knocking the nuclei of the atoms in your body, out of their natural position. As the nuclei realign into the proper position, they send out radio signals. These signals are then received by the computer that processes and converts them to form a two-dimensional (2D) image of the part of the body that is being examined. The image then appears on a viewing monitor for the doctor to see and analyze.
MRI scan uses
What is an MRI scan used to diagnose?
MRI scan can be used to examine different parts of the body, including:
- The brain and spinal cord
- Bones and joints
- Heart and blood vessels
- Internal organs, such as the liver and uterus
If you have a medical condition with any of the above organs, then your doctor would recommend you to get an MRI scan done for proper diagnosis. If you are from Mumbai, India, then get tested at a nearby lab with LabsAdvisor.com.
Following are the types of MRI scans a person can get :
I. MRI scan of the brain
MRI scan of the brain can be useful in evaluating problems such as headaches, weakness, seizures, and blurry vision. It helps us detect certain chronic diseases related to the nervous system of the body.
An MRI of the brain and blood vessels looks for :
- Blood vessel damage
- Brain damage/injury
- Spinal cord related issues
- Eye issues
- Inner ear problems
II. MRI scan of the bones and joints
MRI scan may be used to examine bones, joints, and soft tissues. It may also be used to check the presence of structural abnormalities.
An MRI of the bones and joints looks for :
- Bone infection
- Damaged joints
- Disk problems in the spine
- Neck or lower back pain
For example, an MRI scan of the leg or knee allows the doctor to inspect the parts of the knee that might have been injured during physical activity or from daily wear and tear. It provides us with detailed images of different sections of the knee, including the bones, cartilage, tendons, muscles, blood vessels, and ligaments.
III. MRI scan of the heart and blood vessels
MRI scan of the heart is performed to help your doctor detect or control the cardiac disease by evaluating the function of the heart chambers, heart valves, size, and blood flow through blood vessels.
MRI scan of the heart and blood vessels looks for :
- Damage caused by heart attacks
- Blocked blood vessels
- Problems with the structure of the heart
- Heart disease(s)
IV. MRI of the breasts
MRI scan used with breast ultrasound can be used to detect breast cancer in women with breast implants and in younger women with dense breast tissues. An MRI scan can also locate any abnormal change in the tissue around the breast area (a lesion) which is sometimes missed in ultrasounds.
MRI scan of the breasts looks for :
- Breast cancer
- Breast lesion
- Tumors in the breast
MRI scan preparations
How can I prepare for an MRI scan?
There are a few things you should let your doctor know before you get an MRI scan, including :
- If you have existing health issues, such as kidney or liver disease
- If you have undergone surgery
- If you have any specific allergies
- If you have any breathing issues
- If you are or might be, pregnant
- If you have any tattoos or piercings
- If you have any implants
- If you are carrying any medical devices
Metal is not allowed inside the MRI scan room. All items that contain any type of metal must be removed, some of which include:
- Mobile phone
- Hearing aids
- Dentures (false teeth)
- Underwire (bras)
- Belts and buckles
- Any clothing item that may contain metallic threads
This precaution is taken because the magnetic field in the machine attracts metal. This may cause these items to become hot and burn the patient during the MRI scan.
The patient is also provided with earplugs or headphones during the MRI scan. This helps with blocking out the loud noises of the scanner. These loud noises/sounds are normal and one should not be worried by them. Music is sometimes played in the background which helps calm any anxiety that one may feel.
MRI scan procedure
What is the procedure for an MRI scan?
On arrival at the hospital, the MRI scan procedure usually takes place in the following manner :
- Depending on which part of the body is being examined, the patient is asked to change into a gown
- The patient is then asked to remove all metal items (as mentioned above)
- A form is then filled out by the patient in order to take safety precautions and the patient is free to discuss any issues/concerns with the doctor
- On entering the scanning room, the doctor helps the patient onto the scanner table to lie down, comfortably
- The patient will be provided with earplugs or headphones to block out the loud sounds from the scanner
- The MRI scan will then begin
MRI scan side effects
It is nearly rare that a patient will experience any sort of side effect post an MRI.
However, there are a few cases that should be known to us :
- People who experience claustrophobia or feel uncomfortable in small, enclosed spaces may express difficulties during an MRI scan. Sedation is one way that can be used in such a case.
- Pregnant women should not get an MRI scan during their first trimester unless it is of utmost importance to do so.
How much time does an MRI scan take?
MRI scan is a painless procedure that can last from 30 to 60 minutes or even up to 2 hours. This depends on the part of the body that is being tested, and the number of images being taken.
However, if the images taken are not clear enough, the patient may be asked to undergo another MRI scan again, immediately.