WHAT IS MRI
MRI
Medicine/Medical.
Also called NMR. magnetic resonance imaging: a noninvasive diagnostic procedure employing an MR scanner to obtain detailed sectional images of the internal structure of the body.
magnetic resonance imager. See MR scanner.
Examples from the Web for mri
3 Types of MRI Machines and the Difference Between an Open MRI vs a Closed MRI
Physicians often use magnetic resonance imaging (MRI) to diagnose and treat medical conditions that can be seen only by use of x-ray or magnetic fields and radio frequencies. An MRI machine produces detailed pictures of internal body structures. This radiology imaging technique has improved by great leaps and bounds over the years, leading to the invention of a variety of specialized MRI instruments and equipment. Depending on your symptoms, you may undergo a number of different MRI procedures. Below are three types of magnetic resonance imaging machines commonly used today, but before we briefly discuss the differences in machines (also known as modalities), let’s discuss the difference between a closed versus open mri.
What’s the difference between an open MRI vs a closed MRI?
The difference between an open MRI vs a closed MRI is actually quite simple but first let’s talk about the closed MRI. A closed MRI is a machine that takes detailed images of your anatomy in a narrow cylindrical container normally spanning a bore diameter of 60 cm. Depending on the level of strength of the magnet used (also known as tesla) for your MRI study, the procedure can sometimes last up to 90 minutes or more.
An open MRI was created to offer an alternative to patients who either have symptoms of anxiety or suffer from claustrophobia or obesity due to the enclosed-nature and duration of study normally attributed to closed MRIs. While the open MRI excels at providing comfort, it does not provide the same level of detail as a closed MRI at this time. See an example of a closed MRI on the left and an open MRI on the right.
Three Types of MRI Machines
- Extremity MRI: This is a diagnostic imaging procedure that uses a closed MRI machine to look at the tissues in the arms and legs. Unlike a traditional MRI procedure that uses a large tube-shaped device, an extremity MRI uses a smaller scanner designed specifically for the body’s extremities. This eliminates the potential for claustrophobia, which some patients experience when enclosed in a full-body MRI machine. A traditional MRI requires you to lie completely still, but an extremity MRI won’t limit your body movements quite as much. One may undergo an extremity MRI to diagnose any of the following conditions in the arms, legs, hands, and feet:
- Arthritis
- Fractures
- Bone infections
- Tumors of the bone or soft tissue
- Nerve-related issues
- Stress injuries or injuries related to torsion or heavy impact
- Open MRI: Open MRI machines also stray from the traditional design of the full-body MRI, which makes some patients feel anxious due to the “closed-in” nature of the machine. An open MRI is open on the sides or features wider openings, still requiring the patient to lie on a sliding table. Although an Open MRI offers increased comfortability for patients suffering from anxiety or claustrophobia, it comes at the cost of producing less detailed images than its closed MRI counterparts because the open nature of the machine does not provide as strong of a magnetic field.
- 3 Tesla MRI: This type of closed MRI uses magnetic fields that have double the strength of a traditional MRI machine, thus producing an even more detailed image in less time. It is commonly used to identify the signs of stroke, tumors, or aneurysms in the brain; to examine the heart and circulatory system for damage resulting from a heart attack or heart disease, or blockages in the blood vessels; to look for conditions such as arthritis, disc disease, or bone infections in the bones and joints; or to analyze the state of internal organs like the liver, kidneys, uterus, ovaries, or prostate.
As many as 30 million MRI scans are performed in the U.S. each year, 6.6 million of which are head scans. Your physician will determine which type of MRI is best to diagnose your particular ailment.
A magnetic resonance imaging (MRI) scan is a common procedure around the world.
MRI uses a strong magnetic field and radio waves to create detailed images of the organs and tissues within the body.
Since its invention, doctors and researchers continue to refine MRI techniques to assist in medical procedures and research. The development of MRI revolutionized medicine.
This article looks specifically at MRI scans, how they work, and how doctors use them.
Fast facts on MRI scanning
- MRI scanning is a non-invasive and painless procedure.
- Raymond Damadian created the first MRI full-body scanner, which he nicknamed the Indomitable.
- The cost of a basic MRI scanner starts at $150,000 but can exceed several million dollars.
- Japan has the most MRI scanners per capita, with 48 machines for every 100,000 citizens.
What is an MRI scan?
An MRI scan uses a large magnet, radio waves, and a computer to create a detailed, cross-sectional image of internal organs and structures.
The scanner itself typically resembles a large tube with a table in the middle, allowing the patient to slide in.
An MRI scan differs from CT scans and X-rays, as it does not use potentially harmful ionizing radiation.
Uses
The development of the MRI scan represents a huge milestone for the medical world.
Doctors, scientists, and researchers are now able to examine the inside of the human body in high detail using a non-invasive tool.
The following are examples in which an MRI scanner would be used:
- anomalies of the brain and spinal cord
- tumors, cysts, and other anomalies in various parts of the body
- breast cancer screening for women who face a high risk of breast cancer
- injuries or abnormalities of the joints, such as the back and knee
- certain types of heart problems
- diseases of the liver and other abdominal organs
- the evaluation of pelvic pain in women, with causes including fibroids and endometriosis
- suspected uterine anomalies in women undergoing evaluation for infertility
This list is by no means exhaustive. The use of MRI technology is always expanding in scope and use.
There is very little preparation required, if any, before an MRI scan.
On arrival at the hospital, doctors may ask the patient to change into a gown. As magnets are used, it is critical that no metal objects are present in the scanner. The doctor will ask the patient to remove any metal jewellery or accessories that might interfere with the machine.
A person will probably be unable to have an MRI if they have any metal inside their body, such as bullets, shrapnel, or other metallic foreign bodies. This can also include medical devices, such as cochlear implants, aneurysm clips, and pacemakers.
Individuals who are anxious or nervous about enclosed spaces should tell their doctor. Often they can be given medication prior to the MRI to help make the procedure more comfortable.
Patients will sometimes receive an injection of intravenous (IV) contrast liquid to improve the visibility of a particular tissue that is relevant to the scan.
The radiologist, a doctor who specializes in medical images, will then talk the individual through the MRI scanning process and answer any questions they may have about the procedure.
Once the patient has entered the scanning room, the doctor will help them onto the scanner table to lie down. Staff will ensure that they are as comfortable as possible by providing blankets or cushions.
Earplugs or headphones will be provided to block out the loud noises of the scanner. The latter is popular with children, as they can listen to music to calm any anxiety during the procedure.
