Physics
/
Magnetic Resonance Imaging

Magnetic Resonance Imaging

Shiken premium Upgrade Banner
An MRI Machine

For more than two decades, scientists have been using NMR to create super clear pictures in MRI. This cool technology doctors learn important things about our our organs, the health of tissues, if there are any lumps or bumps (like tumors or infections), and even how our bones are shaped (like in our spines or knees). But instead of calling it NMR, we say MRI to avoid confusion. Some people might think MRI uses scary nuclear stuff, but it doesn't!

The process of producing an MRI scan

The main part of an MRI machine is a huge magnet that makes a really strong magnetic field. This magnetic field is so strong that it interacts with the nuclei of certain atoms (mainly hydrogen). Since a big part of the human body is made up of hydrogen atoms, their nuclei are affected by this magnetic field. This causes them to align in a certain way and create new energy levels. The direction of the alignment depends on the atom's spin, like a north and south pole on a magnet.

The MRI machine turns the magnetic field on and off really quickly using electricity. This is what makes the loud noise in the machine. The hydrogen atoms in the body align and then quickly go back to their normal state. The machine's scanners detect these changes and create an MRI image for the doctor to look at.

Bones don't have many hydrogen atoms, so they don't show up well on the MRI image. They look black. The machine's settings and the type of tissue being scanned affect the colors on the image. Soft tissues like blood and spinal fluid range from black to white in the final image.

There are five types of MRI used today. Functional MRI (fMRI) is used to map out the brain before surgery. Magnetic resonance ven (MRV) creates a picture of the veins. Cardiac is used to image the heart. Breast scans use MRI to look for abnormalities in the breasts. Magnetic resonance angiography (MRA) uses a special dye to look at blood vessels and blood flow.

The advantages and disadvantages of magnetic resonance imaging

Although MRI procedures have many advantages, there are also disadvantages to using MRI techniques. Let’s look at these in more detail.

Advantages

MRI scans are really cool because they can take pictures of any part of the human body and from any direction. They're especially good at creating high-quality images of soft tissues, like muscles and organs. They're even better at telling the difference between different types of tissue like fat, water, and muscle.

The best part about MRI scans is that they don't use any scary nuclear radiation. They're totally safe! MRI scans can also create really precise images of blood vessels, which is super helpful for doctors. They're better at this than other types of imaging techniques.

Disadvantages

While MRI scans are really helpful, they do have some downsides. For one, they happen in a loud and closed space which can be scary for some people, especially those who have claustrophobia. Additionally, MRI scans take longer to complete than CT scans, which can be inconvenient for patients.

Another thing to keep in mind is that the strong magnetic field used during an MRI scan can affect metal devices or structures implanted within the body, like pacemakers or metal plates. It's important to tell your doctor about any metal implants or devices you have before getting an MRI scan.

Magnetic Resonance Imaging - Key takeaways

Magnetic resonance imaging (MRI) is an amazing technique that can produce both two and three-dimensional images of the inside of the human body. It works by using the nuclear magnetic resonance (NMR) effect, which is the interaction between an external magnetic field and certain atoms in the body.

The main part of an MRI machine is a superconductive magnet that produces a strong magnetic field. Electricity is passed through coils to turn the magnetic field on and off in quick pulses. This causes the hydrogen atoms in the body to align in one direction and then quickly return to their normal state. The machine's scanners can detect these changes and use them to create an image.

One interesting thing about MRI scans is that hard bones contain few hydrogen atoms and therefore do not produce a strong MRI signal. This means that bones appear black in the final image. In contrast, MRI scans produce a range of colors between black and white depending on the tissue's hydrogen atoms. This makes them particularly helpful for creating high-quality images of soft tissues and blood vessels.

However, there are some downsides to using MRI scans. One is that they take longer to produce than other types of imaging techniques. Additionally, the strong magnetic field used during an MRI can affect metal devices or structures implanted within the body. It's important to tell your doctor about any metal implants or devices before getting an MRI scan.

Magnetic Resonance Imaging

How does magnetic resonance imaging work?

Magnetic resonance imaging (MRI) works via a superconductive magnet that produces a magnetic field. This magnetic field has a relatively large intensity and interacts with the nuclei of particular atoms (mainly hydrogen). The magnetic field is turned on and off in a series of quick pulses by passing electricity through the coils. In these series of quick pulses, the hydrogen atoms in the body align in one direction and then quickly go back to their normal state. The scanners in the machine detect these changes and produce an MRI image for the radiologist. 

What is magnetic resonance imaging?

Magnetic resonance imaging (MRI) is an imaging technique used in medical physics that produces two- and three-dimensional images of the interior of the human body by creating a magnetic field. 

 What is magnetic resonance imaging used for?

Magnetic resonance imaging (MRI) is used to create images of the inside of the human body. It gathers a lot of useful information about organ function, tumours, infections, conditions of tissue, etc.

How does a magnetic resonance scanner form an image?

A magnetic resonance scanner uses strong magnetic fields that affect hydrogen atoms in the human body, causing them to align in certain directions. The scanners pick up signals from the nuclei of the hydrogen atoms to form an image.

What is an MRI scan used to diagnose?

An MRI scan is used to gather medically useful information about the human body. This information includes the condition of tissues, organ functioning, the presence of tumours, infections, and the shape of bone structures, such as vertebral disks and knee-joint surfaces.

Join Shiken For FREE

Gumbo Study Buddy

Explore More Subject Explanations

Try Shiken Premium
for Free

14-day free trial. Cancel anytime.
Get Started
Join 20,000+ learners worldwide.
The first 14 days are on us
96% of learners report x2 faster learning
Free hands-on onboarding & support
Cancel Anytime