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Abstract #2906

Improved Navigator Performance by Parallel Transmission

Manuel Walther1, Kay Nehrke2, Ingmar Grsslin2, Ulrich Katscher2, Markus Eblenkamp1, Erich Wintermantel1, Peter Brnert2

1Chair of Medical Engineering, Technische Universitt Mnchen, Garching, Germany; 2Philips Research Laboratories, Hamburg, Germany

Parallel transmission has been used to overcome B1 homogeneity limitations and to improve the performance of multi-dimensional RF pulses by shortening their duration. One of the simplest multi-dimensional RF pulses is the pencil beam which finds application as a navigator to sense respiratory motion. As modern high-field systems (3T and beyond) are especially prone to off-resonance effects, shorter pulse durations are necessary to overcome this problem. However, accelerated pulses also cause aliasing artifacts. Transmit SENSE, replacing gradient encoding with transmit sensitivity encoding, has been found to significantly improve the performance of these accelerated navigator pulses, allowing pulse durations of 1.7ms.