(McAb) Monoclonal antibodies are used for tumor detection and localization in nuclear medicine. In MRI, monoclonal antibodies labeled with paramagnetic or superparamagnetic particles are being studied for targeting tumors, for example contrast agent containing gadolinium attached to a targeting antibody. The antibody would bind to a specific target (e.g., a metastatic melanoma cell) while the gadolinium would increase the MRI signal. Further developments are MRI contrast agents that specifically target glucose receptors on tumor cells; coupled with the high spatial resolution of high field MRI devices, these agents have potentials to detect small tumor foci.
The monoclonal antibody manufacturers produce a wide variety of ligands, which can be directed against a multiplicity of pathologic molecular targets. MRI enhanced with targeted contrast agents can be used for molecular imaging.

An implantable medical device that stimulates nerves.

Depending on the used MRI field strength not necessarily a contraindication, but the examination may damage or impair it. In mid to high field MRI machines the reduction of the SAR value during the scan is necessary to avoid the risk of heating.

Open MRI scanners have been developed for people who are anxious or obese or for examination of small parts of the body, such as the extremities (knee, shoulder). In addition, some systems offer imaging in different positions and sequences of movements. The basic technology of an open MRI machine is similar to that of a traditional MRI device. The major difference for the patient is that instead of lying in a narrow tunnel, the imaging table has more space around the body so that the magnet does not completely surround the person being tested.
Types of constructions:
Difficulties with a traditional MRI scan include claustrophobia and patient size or, for health related reasons, patients who are not able to receive this type of diagnostic test. The MRI unit is a limited space, and some patients may be too large to fit in a narrow tunnel. In addition, weight limits can restrict the use of some scanners. The open MRI magnet has become the best option for those patients.
All of the highest resolution MRI scanners are tunnels and tend to accentuate the claustrophobic reaction. While patients may find the open MRI scanners easier to tolerate, some machines use a lower field magnet and generates lower image quality or have longer scan time. The better performance of an advanced open MRI scanner allows good image quality caused by the higher signal to noise ratio with maximum patient comfort.

See also Claustrophobia, MRI scan and Knee MRI.

The interactions between the most tested heart valve prostheses and the magnetic field of MRI devices are of no significance. However, there are many different types of heart valve prostheses and in the particular case their MRI safety should be checked.

Prosthetic heart valves, depending on the type and the material, are not necessarily considered to be dangerous in fields up to 3T. Patients should not undergo high field MRI examinations if valve dehiscence is clinically suspected.

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.