Simultaneous Neuromelanin Sensitive Imaging and Quantitative Susceptibility Mapping by 3D Multi-echo GRE sequence with Optimized MTC Pulse

Although 3D magnetization transfer contrast (MTC) GRE sequence can image neuromelanin and magnetic susceptibility simultaneously, MTC saturation pulse takes too long time, and whether MTC affects accuracy of the susceptibility is unclear. Six subjects were scanned using 3D multi-echo GRE sequences with different durations of MTC pulse. 3D GRE sequence with 5ms of MTC pulse provided same saturation effects in highlighting neuromelanin as 10ms of MTC pulse, and yielded susceptibility values in the deep gray matter nuclei similar to sequence without MTC pulse. Short MTC pulse provides a practical means to simultaneously image the neuromelanin and magnetic susceptibility.