Just a few decades and the use of Magnetic Resonance Imaging (MRI) scanners has sprung up enormously. To name just a few, doctors order MRI scan to help diagnose cancer, multiple sclerosis, torn ligaments, brain tumors, strokes and tendonitis. Without any piercing of instruments into the body, an MRI scan is the most adept way to look inside the human body. Is it really true that this ordeal is truly better than another imaging technique, such as an X-ray or a CAT scan??? Check how.
The Prima Players: MRI Magnets
The main characteristics of a magnet are:
- Type of the magnet used is superconducting electromagnet.
- Strength of the magnet measured in Tesla (T) or gauss. In current clinical practice, these create a magnetic field which varies from 0.5 to 2.0 T.
The magnet is the heart of an MRI system. A horizontal tubes runs through the magnet from front to back. But don’t think that what we are dealing with is just a magnet. This is an unbelievably strong system that is capable of creating an ample and static magnetic field.
Some other Components of MRI
Other components include a patient table which allows sliding the patient in and out of the MRI machine, a very powerful computer system and a set of coils that send radiofrequency waves into the body of the patient. Different coils are used for different parts of the body like the neck, knees, head and wrist and so on. The part of the body which has to be examined determines whether a patient goes in head of feet first. The scanning can began once the body of the patient is at the isocenter of the magnetic field.
Role of atoms in the working of MRI
Billions of atoms that make up the human body are taken into the MRI when the patient slides into the machine for scanning. These atoms spin in random directions around their individual magnetic field. They line up either north or south in the magnetic field produced by the MRI. There may be a few unmatched atoms but atleast half of them go each way. When radiofrequency waves are applied those unmatched atoms spin the other way. The extra atoms return to the normal position emitting energy once the radiofrequency is turned off. This emitted sends signals to a computer which then uses a mathematical formula to convert it into image.
Imaging of MRI
The advantage of MRI scanner is that it can pick out even the minute points inside the body of the patient when required. The system goes point by point into the patient’s body forming a map and then it combines all these to create 3-d or 2-d images using a mathematical formula called FOURIER TRANSFORM. The spinning atoms send the signal to the computer as mathematical data which is then converted into an image.MRI Safety Concerns MRI scanning requires the patients to hold still as long as the tests are being perform and even the slightest movement may cause distorted images which may lead to entire scan being performed again.
There are no known biological risks involved when a patient is exposed to magnetic field of the strength used in MRI machines. So one need not worry about their safety unless they are carrying any metal objects as it may cause serious troubles like being pulled out without any warning towards the opening of the magnet at very high speeds. However patients who have implants like aneurysm clips in the brain, metallic fragments in the eye, dental implants (if magnetic) and so on are preferred to stay away from this type of scanning.Price of the MRI equipment Depending on potency and strength the prices of MRI equipment differs. The more the strength then more is the cost of the equipment as the images produced by it are of high quality. The cost of the MRI machines ranges from $1 to $3 million. The assemblages may require an additional $500,000. The overall cost involved in buying and maintaining of the MRI equipment requires a huge investment. The life-cycle of the machine is assessed to be around 7 years.Hope the magnets of this mighty machine drew you to understand well the working of the MRI machine. These machines are fast evolving so that they are more patient friendly.