An MRI (magnetic resonance imaging) is widely used radiology examination. This imaging technique uses principles of magnetism, radio waves, and a computer to create detailed images of the body structures. Your doctor can use MRI examination to diagnose you or to see how well you have responded to treatment.
MRI is used to produce two-dimensional pictures of internal organs and tissues. Doctors might be looking for variety of disorders, such as:
MRI is also widely used in research to measure brain structure and function. This examination is called functional MRI. In other cases, you may need an MRI with contrast agent to increase the visibility of certain parts of your body.
The MRI scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. The receiver information is processed by a computer, and an image is produced.
In contrast to X-rays and CT imaging techniques, an MRI does not use radiation. However, there are some risks and conditions, when it is better not to undergo an MRI examination, unless it is inevitable. This includes, for example, pregnancy and breastfeeding.
The MRI scanner is operated by a radiographer, who is trained in carrying out imaging investigations. This specialist controls the scanner using a computer, which is in a different room, to keep it away from the magnetic field generated by the scanner. You can talk to the radiographer through an intercom during the examination and they'll be able to see you on a television monitor throughout the scan.
Do you need an MRI examination? Read more here about how to prepare for it.