Optimized noise filters for improved contrast in MRI

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We propose to develop and implement optimized experimental schemes for magnetic resonance imaging (MRI) experiments that modulate the interaction between the nuclear spins and their environment such that the information content of the resulting images is maximized. Depending on the specific diagnostic requirements, it can be optimized to either (i) optimally suppress decoherence (noise) effects in structured media characteristic of living tissue; (ii) optimally measure and analyze the noise spectra, and extract diagnostic information from the noise. For both goals, the optimal modulation scheme must be robust against experimental imperfections that are typically encountered in a clinical environment and keep the SAR values at acceptable levels. We expect that such optimally designed field modulation schemes will result in substantial improvements in signal-to-noise ratios and / or generate images that provide more direct information, e.g. on molecular diffusion processes in the tissues. The sequences will be designed with the help of optimal control theory, building on a substantial amount of expertise in the group in Dortmund as well as in the group of Gershon Kurizki, our cooperation partner in Israel. Initial experiments will be performed on a high-resolution NMR spectrometer. This allows for more measurement time, avoids many of the complications associated with clinical scanners and allows the most direct comparison between theory and experiment. When the initial checks are completed, we will move the experiment to a microimaging system that allows well-controlled tests of all aspects that require spatial resolution. To test aspects that are specific to whole-body imaging systems, we will implement the experiments on the 7 Tesla MRI scanner of the Erwin Hahn Institute. As the ultimate result, we expect that clinical MRI will have new tools at its disposal that significantly extend the diagnostic toolset of MRI.