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Broadband RF pulses for cardiac MRI


The separate imaging of fat and water rich tissue is a frequent objective in magnetic resonance imaging (MRI). An efficient solution is provided by the Dixon technique where both compartments are excited simultaneously and the signals are later separated based on their different temporal evolution. At the 'ultrahigh' MRI field strength of 7T, the frequency shift between fat and water protons is large. This helps to separate both signals but now the simultaneous excitation becomes a problem. This is particularly true when a large field-of-view like the human chest is to be imaged, where both the static magnetic field B0 and the radiofrequency (RF) magnetic field B1+ tend to be inhomogeneous. Christoph Aigner and coworkers from PTB's Ultrahigh Field MRI group 8.14 now developed a new class of broadband RF pulses for cardiac MRI at 7T providing homogeneous excitation of both fat and water rich tissue over the whole heart. In their recent paper "Tailored and universal parallel transmit broadband pulses for homogeneous 3D excitation of the human heart at 7T" (Magnetic Resonance in Medicine 2024, doi: 10.1002/mrm.30072) the authors demonstrate that both subject-specific 'tailored' pulses as well as calibration-free 'universal' pulses are available.


Christoph Aigner, E-Mail: 📧 christoph.aigner(at)ptb.de