How MRI Works?
An MRI scanner consists of a large and very strong magnet in which the patient lies. A radio wave antenna is used to send signals to the body and then receive signals back. These returning signals are converted into pictures by a computer attached to the scanner. Pictures of almost any part of your body can be obtained at almost any particular angle and plane. The triple-layered icing on the cake is, MRI has absolutely no side effects, it is completely painless and is non-invasive as well.
What is a Tesla?
The Tesla is a unit to measure the strength of a magnetic field. It is symbolized by the letter T, and is named in honour of Nikola Tesla, considered the father of modern electrical engineering, the man who pioneered the radio.A magnetic field of 1 Tesla will be about 30,000 times as powerful as the earth’s magnetic field, but magnetic fields of high Teslas can be achieved by concentrating magnetic power in a small space. A very powerful superconducting electromagnet generates a magnetic field which is about 20 T strong.
What does the equipment look like?
The traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table that slides into the center of the magnet.Some MRI units, called short-bore systems , are designed so that the magnet does not completely surround you; others are open on the sides (open MRI). These units are especially helpful for examining patients who are fearful of being in a closed space and for those who are very obese.
Experience during the MRI Scanning - I
You will be asked to remove all jewelry and metal abjects like hairclips and detachable dental fixtures.You will be made to lie on a special table that moves into the center of the magnet. Prior to going into the magnet you will be offered earplugs or head phones to reduce the noise that you hear.You might hear some “hammering” noises while the scanner is preparing to work. At this time, it is important not to move, as movement will blur the pictures.
Experience during the MRI Scanning - II
You may also feel some vibration during the hammering noise and some slight movement of the table during the examination.Some patients may be given an injection of a substance called a 'contrast agent', for imaging purposes. This agent is very safe.Depending on the area being scanned, you may also be asked to hold your breath for few seconds.
Experience during the MRI Scanning - III
The scanning staff will be in another room, but will keep you and the equipment within sight through a glass panel and CCTV. You will be able to communicate with the staff and vice versa by means of microphones and you will also normally have access to a bell by means of which the staff can be called.
How safe is an MRI?
MRI is the safest among the imaging modalities. MRI scanners are good at looking at the muscles, ligaments, and tendons of 'soft tissues' of the body. In particular, the brain, spinal cord and nerves are seen much more clearly with MRI that with regular X-Ray and CT scans.. An MRI scanner uses no X-Rays or other radiation.
How safe is an MRI?
- No ionizing radiation
- No known biological hazards
- High-resolution-isotropic images (3D images)
- Excellent soft tissue contrast – Opportunity to interpret pathological changes
- MRI is usually non-invasive- imaging of blood vessel without contrast injection
- Dynamic imaging of joints and the heart
How safe is an MRI?
Some patients may not be able to have an MRI scan. They include people who get nervous in small spaces (claustrophobic) and those with implanted medical devices such as aneursm clips in the brain, heart pacemakers and cochlear (inner ear) implants. Also, people with pieces of metal close to or in a vital organ (e.g. the eye) may not be scanned. There are a few additional safety considerations and some exceptions based on individual circumstances.