From Siemens Medical Systems;
Received FDA clearance in 2012.
The MAGNETOM Spectra is a cost-optimized high field MRI system with Tim 4G and Dot technologies. The system consumes less energy compared to other 3 Tesla scanners. The magnet-cooling helium is contained in a closed loop, which prevents the gas from escaping and reduces the need for refills. TimTX includes innovative techniques in the radio frequency excitation hardware as well as new application and processing features enabling uniform RF distribution in all body regions.

From Siemens Medical Systems;
The Magnetom Trio™, a 3T whole body MRI system with Tim (total imaging matrix technology), targets clinical applications such as abdominal, cardiac, spine, whole body and orthopedics. TIM enables flexible coil combinations for high resolution imaging of large anatomical areas without the need to change coils.

There are different types of contraindications that would prevent a person from being examined with an MRI scanner. MRI systems use strong magnetic fields that attract any ferromagnetic objects with enormous force. Caused by the potential risk of heating, produced from the radio frequency pulses during the MRI procedure, metallic objects like wires, foreign bodies and other implants needs to be checked for compatibility. High field MRI requires particular safety precautions. In addition, any device or MRI equipment that enters the magnet room has to be MR compatible. MRI examinations are safe and harmless, if these MRI risks are observed and regulations are followed.

Safety concerns in magnetic resonance imaging include:

It is important to remember when working around a superconducting magnet that the magnetic field is always on. Under usual working conditions the field is never turned off. Attention must be paid to keep all ferromagnetic items at an adequate distance from the magnet. Ferromagnetic objects which came accidentally under the influence of these strong magnets can injure or kill individuals in or nearby the magnet, or can seriously damage every hardware, the magnet itself, the cooling system, etc.. See MRI resources Accidents.
The doors leading to a magnet room should be closed at all times except when entering or exiting the room. Every person working in or entering the magnet room or adjacent rooms with a magnetic field has to be instructed about the dangers. This should include the patient, intensive-care staff, and maintenance-, service- and cleaning personnel, etc..
The 5 Gauss limit defines the 'safe' level of static magnetic field exposure. The value of the absorbed dose is fixed by the authorities to avoid heating of the patient's tissue and is defined by the specific absorption rate. Leads or wires that are used in the magnet bore during imaging procedures, should not form large-radius wire loops. Leg-to-leg and leg-to-arm skin contact should be prevented in order to avoid the risk of burning due to the generation of high current loops if the legs or arms are allowed to touch. The patient's skin should not be in contact with the inner bore of the magnet.
The outflow from cryogens like liquid helium is improbable during normal operation and not a real danger for patients.
The safety of MRI contrast agents is tested in drug trials and they have a high compatibility with very few side effects. The variations of the side effects and possible contraindications are similar to X-ray contrast medium, but very rare. In general, an adverse reaction increases with the quantity of the MRI contrast medium and also with the osmolarity of the compound.

See also 5 Gauss Fringe Field, 5 Gauss Line, Cardiac Risks, Cardiac Stent, dB/dt, Legal Requirements, Low Field MRI, Magnetohydrodynamic Effect, MR Compatibility, MR Guided Interventions, Claustrophobia, MRI Risks and Shielding.

From Toshiba America Medical Systems Inc.;
OPART™ is a 0.35 T superconducting open MR system featuring cryogenless operation. Superconducting speed and performance are combined with the patient access advantages of open MRI design for unmatched clinical versatility. OPART™ features innovative technologies such as digital RF, high speed gradients and optimized RF coils, which support advanced MRI applications.

Quenching is the cryogen boil off (liquid helium) which is used to cool the superconducting magnet coils of high field MRI systems. This results in a loss of superconductivity in the magnet, in a rapid increase in the resistivity of the magnet, which generates heat that results in further evaporation of the cryogen.

A quench can cause total magnet failure and should be avoided.