What is the function of the gradient system in MRI?

The gradient system in MRI is essential for spatial localization of the magnetic resonance (MR) signal. It accomplishes this by producing linear variations in the magnetic field across the imaging volume. When the gradient coils are activated, they change the strength of the magnetic field in a controlled manner, allowing specific frequencies of the emitted radiofrequency (RF) signals to be associated with particular spatial locations in the body.

This spatial encoding is crucial for creating detailed images of the anatomy, as it enables the determination of where in the body the signals originate. Consequently, the system helps in distinguishing between different tissues and structures, providing the foundation for the MRI's imaging capabilities.

The function of the gradient system does not involve creating non-linear variations in the magnetic field, generating RF signals, or enhancing image resolution through cooling, which distinguishes it from other components of the MRI system, like the RF coils or the overall imaging protocol.