Components in an MRI Machine

A magnetic resonance imaging (MRI) machine is a complicated device that relies on a combination of sophisticated technologies for smooth operation. Each component in an MRI machine serves its own unique function. Main examples of these components include:

The Magnet

All MRI machines are built around a powerful magnet that generates a stable magnetic field capable of encompassing an entire human body. Types of these components used by various manufacturers include permanent magnets, resistive magnets and superconducting magnets. Most MRIs contain superconducting magnets.

Gradient Coils

During operation, an MRI must distort the magnetic field in a precise and reliable way in order to produce accurate images. Gradient coils are used for this purpose. Essentially, these coils change the strength of the generated field at various points in patients’ bodies.

Shim Coils

This component is used to make sure that the magnetic field produced for imaging has an overall uniform level of strength. In turn, this uniform strength promotes image accuracy.

Radio Frequency Coils

All MRIs use radio waves to relay the images of each patient’s body. Radio frequency (RF) coils produce the required waves. There are three types of these coils used to send signals into the patient and produce images: head coils, body coils and surface coils.

Computer

A computer controls the commands sent to a magnetic resonance imaging machine, and also controls the power supplies for the gradient coils and the radio frequency transmitter. The same computer receives the raw radio frequency data from each scan and makes a viewable image from that data. In addition, the computer relays the viewable image data to a monitor, as well as to a device that makes film hard copies of each image.

Problems with any one of the components in an MRI machine can degrade the quality of the images produced by scanning. Since such a loss of quality is unacceptable, each machine must undergo periodic inspection.