Types of MRI Machines, Exams, Tests and Scans

Magnetic Resonance Imaging (MRI) works by using magnets and radio waves to create a series of detailed pictures of your organs from many different angles. It’s painless, non-invasive (meaning it does not involve any needles), which makes it perfect for scanning infants and people with severe health conditions.

A common misconception about the procedure is that it sends strong bursts of energy into the body; this isn’t true at all. There’s no radiation involved in MRIs whatsoever – only safe magnetics! The most common side effect is claustrophobia.

An MRI machine or scanner is a device that uses magnetic fields and radio waves to create images of the inside of the body.

MRI machines are a central part of modern medical technology. There are different types of machines, depending on what type of scan is needed.

It should be noted that MRI types may refer to the design, type of MRI machine or even the purpose (and technique) of the scan or exam. The type of machine or scan an individual requires depends on his or her conditions and needs.

Types of MRI Designs

Under this classification, we consider only the design in which the MRI machine is set up, and the two main designs are open, closed, and stand-up MRI designs.

#1 Open Design

Open MRI machines have an open design that allows for more space in which patients can move around during the procedure as well as better access to equipment such as tables or stretchers so they can be moved into position without having to exit the scanner.

Open MRIs have the advantage of being able to accommodate larger patients, but they also tend to be less expensive than their closed counterparts.

#2 Closed Design

Closed MRI machines have a much smaller opening where only one patient may fit at a time with their head in close proximity to all parts of the scanner including large magnets and other moving parts that could potentially injure the patients.

Closed MRIs offer higher resolution images, but may not be compatible with individuals who cannot lie still for long periods of time due to claustrophobia or anxiety disorders such as panic attacks and post-traumatic stress disorder (PTSD).

Doctors often need access to high-quality imaging equipment in order to provide accurate diagnoses for their patients, which is one reason why some doctors prefer closed MRIs over open ones.

Types of MRI Machines

there are three different types of Magnetic Resonance Imaging scanners based on the machines namely Full-body, Extremity, Open, and Tesla MRI scanners and machines.

1. Full-body (Traditional) MRI Scanner

A full-body MRI scanner is a device in which in order to generate comprehensive images of the inside of your body, it makes use of a strong magnetic field, radio waves, and computer technology.

It may be used to aid in the diagnosis or monitoring of therapy for a range of diseases affecting the chest, abdomen, and pelvis, among other areas of the body.

If you’re expecting a child, a body MRI may be utilized to carefully monitor your unborn child.

2. Extremity MRI Scanner

An Extremity MRI machine is a device that is used to take pictures of the limbs. It can be used to diagnose many different problems including carpal tunnel syndrome.

The images are taken in order for the doctor to be able to see what might have caused the problem, or if there are any other issues going on that could worsen or become an issue.

It makes use of a relatively small scanner that is tailored to the body’s extremities. This removes the risk of claustrophobia, which can occur when a person is encased in a full-body Mri scanner.

The Extremity MRI machine provides images of the bones, muscles, joints, and tendons that are located in your extremities.

This is a great tool for doctors to assess if there is an injury or disease affecting these areas which may include, bone tumors, soft-tissue tumors, fractures, arthritis, bone infections, stress injuries and nerve-related issues.

If you’re considering getting one for your healthcare practice, here are some things to consider:

  • The cost of the machine and its maintenance
  • Size considerations (they come in different sizes)
  • The space required
  • The type of warranty it has

3. Open MRI (OMRI) Scanner

Open MRI Machine (OMRI) is a non-smaller open magnetic resonance imaging scanning machine that offers more space and greater operating flexibility.

They depart from the typical design of the full-body MRI, which might cause some patients to feel uneasy owing to the “closed-in” aspect of the scanner, which some patients find unnerving.

An open MRI is one that is open on the sides or has bigger apertures, but it still requires the patient to lie on a sliding table during the procedure.

Because of the open design of the scanner, it produces less clear images than its closed MRI equivalents, despite the fact that it is more comfortable for individuals who suffer from anxiety or claustrophobia.

They can be set up in line, horseshoe, or pit configurations without the sheet metal enclosure around the magnet that reduces patient access to tables and controls.

The pillow coil surface area can also be increased for some scanners and is often installed at ground level to accommodate patients with wheelchair ramp access from an external loading dock.

These machines have been designed for modalities including positron emission tomography (PET), CT scans, angiography scans, fluoroscopy procedures, and nuclear medicine procedures such as cardiac stress testing.

4. Tesla MRI Scanner

The Tesla MRI machine is a newer class of MRI instrument designed by the Advanced Imaging Research Center.

This type of MRI, or tomography imaging technique, makes use of magnets with strong magnetic fields and narrow aperture to help provide a clearer image than that typically obtained using an echo-based magnetic resonance system or comparably sized unit.

Tesla rotorless synchronous motors are used within the scanner to achieve faster scanning experiments without producing any interference on the desired signal-to-noise ratio and accuracy levels for MR studies.

In some cases, it can detect tumor changes in as little as two days while traditional magnetics may take up to three months for similar detection revelations with more clarity in diagnosis and subsequent medical treatments.

When used for the brain, it is often used to check for symptoms of a stroke, a tumor, or aneurysms.

When used for the heart and circulatory system, it is often used to look for damage from a heart attack or heart disease or blockages in the blood vessels.

When used for the limb bones and joints it is used to check for diseases including arthritis, disc disease, or bone infections.

5. Upright (Stand-Up) MRI

An Upright MRI (also known as a Stand-Up MRI) is a technological breakthrough in medical diagnostics that has the potential to revolutionize the field.

The Stand-Up MRI, which has a front-open design, allows radiologists to scan patients in a variety of different postures.

Types of MRI Exam Techniques

The MRI scans and exams are requested by doctors when they want to check for specific problems within the body. It is for this reason that MRI scans differ in each case depending on the requests of the physician,

In this section, we explore the various types of MRI scans, exams, or testing techniques, which are:

#1. Functional MRI

Functional MRI (fMRI) is a groundbreaking way of viewing the brain in action by examining changes in blood flow.

Since regular MRI scans only show structures, they can not tell scientists whether the brain is properly sending messages to different parts of the body.

fMRI creates a three-dimensional map by which the scientist can get a glimpse into how neurons and other cells are connected; it will reveal activity patterns, for example, which helps doctors diagnose what needs treatment.

An fMRI may also be ordered by a physician for the purpose of brain mapping. Brain mapping is required for brain surgery, as well as for the detection of epilepsy and malignancies.

#2. Magnetic Resonance Venography

Magnetic Resonance Venography (MRV) is the technical term for the type of MRI scan that is used to assess patients’ venous system, such as if there are blockages present, but an MRV scan can also evaluate other aspects of the venous system, such as blood clots or obstruction.

A Magnetic Resonance Venography (MRV) defines all vessels in a certain area by mapping their cross-sections with a magnetic vector field.

As one might imagine from what was just explained, it’s not an easy procedure for doctors to use because they have to distinguish between veins and tissue in order to follow them completely without missing anything.

#3. Magnetic Resonance Angiography

Magnetic Resonance Angiography (MRA) is a non-invasive diagnostic method that visualizes blood arteries using a combination of magnetic resonance technology (MRI) and intravenous (IV) contrast dye.

It is a medical imaging technique to visualize the detailed anatomy of blood vessels and permits assessment of the severity of artery disease.

One of the most important cardiovascular conditions that can be assessed with magnetic resonance imaging is carotid artery stenosis, which often precedes sudden death.

An MRA can also provide information about the vessel wall thickness and characteristics of atherosclerotic plaques, such as calcification or extension into smaller branches among other diagnostic information not obtained or available using traditional MRI scans.

On an MRI image, contrast dye makes blood vessels look opaque, allowing the physician to see the blood vessels under examination. An MRA is commonly used to evaluate blood flow and check the heart and other soft tissues.

#4. Non-contrast MRA

It is possible that some patients will be unable to tolerate contrast dye. This is especially true for people who are suffering from renal issues. Historically, these patients were unable to have MRAs performed on them.

However, it is now feasible for all patients to have MRAs performed utilizing modern diagnostic technologies that eliminate the need for dye while maintaining crystal-clear pictures in the process.

#5. Cardiac (Heart) MRI

A cardiac MRI is a diagnostic method or medical imaging technique that produces precise pictures of heart structures using a powerful magnet, radio frequencies, and a computer. The heart MRI is best done when the heart is in a resting beat.

#6. Breast MRI

Patients who are at a high risk of developing cancer of the breast should get an MRI. While this is a non-invasive technique, physicians may request a needle biopsy of the breast guided by an MRI.

Breast cancer can be detected via an MRI, which also provides information about the tumor’s development and location.

It is important to mention that most MRI breast examinations are performed with the patient lying down, and without any metal.

Generally, there should be no problem unless the implant is made of ferrous metal, or if it’s made of silicone because they’re sometimes more sensitive to changes in magnetic fields.

#7. Brain Magnetic Resonance Spectroscopy

Magnetic resonance spectroscopy is a powerful non-invasive technique that can be used to assess the structure and dynamics of molecules within cells. It relies on nuclear magnetic moments of certain atoms such as water or fat, and hydrogen nuclei in general.

This technique provides chemical information for intracellular materials without destroying or damaging the cell.

Measurements are done by applying a radio frequency magnetic field which disrupts magnetization from this proton (or other nuclei) and causes the nucleus to start spinning out of synch with its surroundings.

It is often used to investigate the metabolic alterations produced by strokes, brain tumors, Alzheimer’s disease, seizure disorders, disease, and other brain disorders.

References:

  • 1: Types of Magnetic Resonance Imaging (MRI) Exams – Stanford Health Care
  • 2: Different types of MRIs – Independent Imaging
  • 3: 3 Types of MRI Machines and the Difference Between an Open MRI vs a Closed MRI
  • 4: An Introduction to Different Types of MRI – PBMC Health

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