Introduction
Magnetic resonance imaging (MRI) scan is a painless non-invasive medical procedure that uses strong magnetic field and radio waves to produce very clear images of internal body organs and structures. Strong magnetic and radio waves are used by this imaging technology to create three dimensional detailed anatomical images.
Facts & Figures
Key facts and statistics about MRI scanning
- It is a non-invasive, painless medical procedure.
- The first MRI full body scanner was created and invented by Raymond Damadian.
- Having 48 MRI machines for every 100,000 nationals, Japan stands as the country with the highest number of scanners per capita.
Indications/Uses
Brain and spinal cord MRIs can be used assess, evaluate and diagnose:
- Brain aneurysms.
- Multiple sclerosis.
- Stroke.
- Brain and spinal tumors.
Body MRIs can be used for evaluation of structures and diagnosis of various conditions, such as :
- Vasculitis.
- Tumors.
- Liver cirrhosis.
- Fetal development in the body.
Functions of bone and joint MRI include:
- To evaluate bone tumors and infections such as osteomyelitis.
- To assess joint problems as a result of injuries.
Heart MRIs can be used for:
- Diagnosing cardiovascular conditions such as infections and inflammatory conditions.
- Evaluation of anatomy and function of the heart in persons with congenital heart disease.
- Assess and evaluate functions and anatomy of the heart chambers and heart valves.
Preparation & Details
- MRI test take around 30 to 50 minutes to be completed.
- Radiologists perform MRIs. They also interpret imaging tests to diagnose medical conditions.
- MRI machines have very strong magnets.
- For MRI to work, electric current is passed through coiled wires and a temporary magnetic field is created inside the human body. A transmitter located in the machine sends radio waves then receives them again. These signals are used by a computer to create digital images of the region of the body which is scanned.
- Individuals who have implanted devices should make their healthcare provides aware of these as this medical procedure can lead to malfunctioning of these devices.
- Healthcare specialists should also be notified of:
- Pregnancy.
- Claustrophobia.
- Inability to lie on the back for more than one-half of an hour.
Types
Two main types of MRI machines are closed bore and open MRI machines. There is also another type; wide bore MRI machine.
Closed bore MRI machine
It is used to capture highest quality images.
Open bore MRI machine
It has two flat magnets located below and above the space where the patient is placed.
It does not take clear images a s compared to closed bore MRI machine.
Wide bore MRI machine
Contrast
MRI with contrast
In some MRI examinations, an injection of a contrast material is given intravenously and it contains a metal called gadolinium. This metal changes the magnetic properties of nearby molecules of water, therefore image quality is enhanced.
The contrast material enhances the visibility of:
- Blood vessels.
- Tumors.
- Inflammation.
- Infection.