3T in der neuroradiologie - Spannungsfeld zwischen wunsch und wirklichkeit

Progress in MR technology depends on a variety of parameters. Overcoming the inherent poor signal to noise ratio (SNR) by increasing the field strength has been a successful strategy for the past, however, switching from 1.5T to 3T has disclosed several problems including increased specific absorption rate (SAR), striking susceptibility artifacts especially at the base of the scull, and low contrast on T1-weighted images. These drawbacks had to be compensated by additional procedures like parallel imaging, new sequences, and special measures for distortion correction. Consequently, induced by the increase of the field strength to 3T a new and more complex platform for MRI was developed. Benefits of 3T in comparison to 1.5T are already evident regarding fMRI, MRA and perfusion imaging with spin labeling. In addition, there is improved signal quality for spectroscopy at higher field strength, but also an unexpected loss in sensitivity of lactate, which can only be compensated by an additional measurement. At present, T1-weighted images of the spine are unsatisfactory and have to be improved. The increasing importance of MRI in neuroscience will drive further installations of 3T scanners inside of brain imaging centers. In this environment, the role of neuroradiology has to be adjusted as an important player that participates in development and application of this promising new technology.