What type of MRI unit uses a cryogen?

The type of MRI unit that uses a cryogen is a superconducting MRI unit. Superconducting magnets rely on the principle of superconductivity, allowing them to maintain a magnetic field without electrical resistance when cooled to very low temperatures, typically with liquid helium. This cryogenic cooling is essential as it enables these magnets to achieve and maintain their necessary magnetic strength, which is crucial for producing high-quality images in an MRI.

In contrast, resistive MRI units use electrical resistance to generate a magnetic field, and they do not require a cryogen for operation. Permanently magnetized units, as the name implies, use permanent magnets and also do not rely on cryogens. Therefore, only superconducting MRI units utilize cryogens for maintaining the required operating conditions. This characteristic distinguishes them from other types of MRI systems.