The compact 3T MRI system has been in continuous operation at the Mayo Clinic since March 2016. To date, over 200 patient studies have been completed, including 96 comparison studies with a clinical 3T whole-body MRI. The increased gradient performance has reliably resulted in consistently improved image quality.

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The authors have reported the results of low n-value from a MgB 2 test coil developed a year ago. A second test coil has been developed with wire of different structure and manufacturing process. Although the n-value related voltage of the second test coil was lower than the first test coil at designed current, it still showed low n-value. A third test coil has been wound with reduced mechanical stress. It also showed very similar n-value related voltage and n-value. Investigation of voltage distribution over the coil indicated that magnetic field was the major factor causing degradation of the n-value and resulting in n-value related voltages. Since the n-value related coil voltages were on the order of 0.1 μV/cm, the usual short sample I c test (1 μV/cm was the definition of I c ) might not detect the n-value related voltage and might not be able to investigate the cause of low n-value. Therefore, the medium length (∼10 m) samples were tested and they showed the wire's lengthwise nonuniformity both on n-value and I c , which might be another potential cause of the low n-value of the coil. Along with the electrical investigation, the manufacturing process of the wire was carefully inspected for longitudinal uniformity. Some wire segment samples from the same batch exhibited nonuniformity in the particle size distribution resulting in nonuniform filaments. This might have occurred in the wire for the second and third test coils.

An test coil was manufactured and tested as the first step in the development of a 3 T magnet system. Due to the fact that has a higher critical temperature, replacing conventional NbTi superconductor with , higher temperature operation will be possible. It will make the cryogenic design much simpler and less expensive.Furthermore, operating the magnet at higher temperature results in larger heat capacity of the materials and surrounding structures. Higher heat capacity, therefore, results in increased thermal stability of the magnet against quench initiation.The 3 T magnet design consists of several coils. One of the center coils was manufactured for testing the performance at higher temperatures. The test coil was conduction cooled and the quench performance of the coil was good, which means there were no critical issues during the coil manufacturing process. However, AC loss heating, as well as a small resistance of the coil was found, both of which might result from wire design, manufacture, and quality.

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