Wireless local transmit coils and array with controllable load

摘要

A local radio frequency (RF) transmitting coil (26) of a magnetic resonance imaging system (5) has a plurality of coil elements (100). Each coil element (100) has an adjustable load (62) which is adjusted by a control unit (60) to adjust a transmitted B1 field distribution. The load can be adjusted to shim for a uniform B1 field distribution. Non-uniform B1 field distributions can be selected to perform magnetic resonance sequences that use such B1 field distributions, such as parallel imaging. The B1 field distribution can be changed during the magnetic resonance sequence to track a moving region of interest, time division multiplex parallel imaging, and the like.

主权项

1. A magnetic resonance system comprising:
a main magnet which generates a static (B0) magnetic field in an examination region; magnetic field gradient coil which superimposes time varying magnetic field gradients on the B0 in selected directions within the examination region; a whole body radio frequency coil which generates radio frequency (B1) pulses; and a local radio frequency coil inductively coupled to the whole body radio frequency coil, the inductively coupled local radio frequency coil for a magnetic resonance system comprising: a plurality of radio frequency coil elements each including an adjustable load, the load having at least one of an adjustable capacitance, resistance or impedance; and a control unit which includes:
a load controller which controls adjustments of the load; anda communications interface connected to the load controller which communicates between the load controller and an off-coil controller.