7-T Magnetic Resonance Imaging in the Management of Brain Tumors

Although UHF MR imaging is advantageous in providing information that is complementary to the current capabilities of 1.5-T and 3-T systems, it remains to be seen whether it will replace state-of-the art 3-T scanners in the same way that 3 T has supplanted 1.5 T for brain tumor imaging. The progress of UHF imaging systems has been limited by technical challenges caused by nonuniform static (B0) and RF (B1) fields, higher specific absorption rates resulting in tissue heating, and magnetic susceptibility artifacts that still remain, despite numerous methodological advances to date. To optimally leverage the advantages and maximize the potential of UHF for clinical applications, diverse strategies need to be introduced, such as incorporating multitransmit developments that have been shown to mitigate field inhomogeneity into robust, user-friendly applications for routine clinical use. As more 7-T scanners become available and gain FDA 510(k) clearance, more confirmatory studies are likely to emerge in these areas, followed by larger, prospective, multicenter trials that will weigh the advantages of UHF imaging for brain tumor management against its disadvantages, including patient contraindications that cannot be overcome by technical strategies. The success of these systems will ultimately depend on the new information that can be attained that is not technologically possible at lower field systems, as opposed to incrementally improving the quality of the current 3-T standard.