Self-generating and self-receiving birdcage array coil and its control circuit

Abstract

Provided is a self-transmitting and self-receiving birdcage array coil, comprising: a first end ring, on which is provided a plurality of first end ring capacitors; a second end ring, on which is provided a plurality of second end ring capacitors; a plurality of legs, lower ends of which are connected to the first end ring, and upper ends of which are connected to the second end ring; and a ring body, which is provided between the first end ring and the second end ring, wherein directions of diodes on each leg are the same, directions of diodes on adjacent legs are the opposite, and the ring body is provided with a plurality of third capacitors. Also provided is a control circuit for the self-transmitting and self-receiving birdcage array coil, which uses at least a two-level power divider so that each of two or more birdcage coils obtains an orthogonal signal pair with equal power, equal feed is conducted on each coil, and each transmit-receive control sub-circuit includes a power divider, an emission control circuit, a transmit-receive isolation circuit and a reception amplification circuit. The present application solves the problem of a low signal-to-noise ratio of each birdcage radio-frequency coil, and the problem of coupling interference between an emission coil and a receiving coil.

Description

technical field [0001] The invention relates to a self-generating and self-receiving birdcage array coil and a control circuit thereof. Background technique [0002] At present, the general birdcage coil (also known as birdcage coil, BC for short) requires its diameter (D) and length to be basically the same or the length (L) to be slightly smaller than the diameter in design, otherwise the coil’s emission efficiency will be reduced, so the current birdcage coil Cage coils basically adopt the principle of D≈L. In order to further improve the signal-to-noise ratio of the birdcage coil as a receiving coil, Uli Gotshal et al. proposed to use two birdcage coils or multiple birdcage coils in the longitudinal direction. For a single birdcage coil, D≈2L , forming a birdcage array coil, compared with a single birdcage coil with the same diameter and length, the signal-to-noise ratio will be increased by 15-20%. [0003] Because birdcage coils can produce very uniform image quality...

AI Technical Summary

Problems solved by technology

However, if a large birdcage coil (excitation voltage over 600V) is used to excite smaller objects to be scanned, such as the human head, limbs (including wrists, arms, knees, ankles, etc.), or animals (such as cats and dogs, mice, Rabbits, etc.), due to the restrictions on the safety index of radio frequency absorption rate SAR (specific absorption rate) by regulations, the emission energy cannot be effectively transmitted to the scanned object, which will reduce the emission efficiency, further optimize the image scanning parameters, and sacrifice Image SNR and Resolution

For this reason, someone proposed to adopt a local radio-frequency coil device with integrated transceiver, that is, a birdcage coil with a suitable size (determined according to the size of the scanning object) is used as the transmitting layer, and the inner layer adopts a phased array surface radio-frequency coil as the receiving layer. This can indeed improve the transmission efficiency and the receiving signal-to-noise ratio of the image, but at the same time it will complicate the design of the coil, and the coupling between the transmitting layer and the receiving layer is difficult to eliminate fundamentally.

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