What is MRI?

A mother comforting her son in the AIRISŽ II Open MRI equipment while the nurse answers any questions. Magnetic Resonance Imaging (MRI) is a method used by physicians to look inside the human body to obtain diagnostic information. Incorporating an advanced technology, MRI uses a computer and the physical properties of magnetic fields and radio waves to generate images of the soft tissues within the body without the use of radiation found in x-ray and CT scanning.

You are placed inside a strong magnetic field for your examination. This causes the hydrogen atoms in your body to align themselves in a position to receive radio signals. Your body responds and transmits signals of its own that are processed by a computer and made into images or pictures. The pictures produced assist your doctor in diagnosing health problems at their earliest, most treatable stages. This technique is commonly used as a primary diagnostic tool and in many cases, MRI eliminates the need for additional diagnostic procedures.

It can help provide a quick and accurate diagnosis for your physician, which in some situations can reduce the need for exploratory surgery and other diagnostic procedures which might have associated risk.

MRI is a non-invasive procedure, and there are no known side or after effects. The procedure is painless; in fact, you won't see or feel anything. A faint knocking sound will be heard which is simply the imaging process in operation.

Magnetic Resonance Imaging (MRI) systems are able to generate high quality diagnostic images through the use of a powerful magnetic field. Magnetic resonance images are formed by the computer processing of signals that are emitted by body tissue. These signals are generated using a safe magnetic field in combination with radio waves of a specific frequency.

Hydrogen protons within the body align with the magnetic field. By applying short radio frequency (RF) pulses to a specific anatomical slice, the protons in the slice absorb energy at the resonant frequency causing them to spin perpendicular to the magnetic field. As the protons relax back into alignment with the magnetic field, a signal is received by a RF coil that acts as an antennae. This signal is processed by a computer to produce diagnostic images of the anatomical area of interest.

Different tissue characteristics are revealed through this process and translated into different contrast levels on the image. These contiguous thin slice images can be obtained in various planes for optimum clinical evaluation.

How does the MRI machine work.

This is what the AIRISŽ ll Open MRI control console looks like.

The magnetic field is used to align hydrogen protons in the body.
Radio frequency waves are absorbed by the protons and then emitted as a signal.
A radio frequency coil picks up the signal and transmits it to the computer.
The computer processes the data and an image is generated.