Patent Application
20140176137
This application claims the benefit of CN 201210555182.X, filed on Dec. 20, 2012, which is hereby incorporated by reference in its entirety.
The present embodiments relate to the technical field of magnetic resonance imaging.
Magnetic resonance imaging (MRI) is a technology for imaging by use of magnetic resonance. Magnetic resonance includes that an atomic nucleus with an odd number of protons (e.g., a hydrogen atomic nucleus, which widely exists in the human body), the protons have spinning motion, like a small magnet, and the spin axes of these small magnets do not have a certain orientation. If an external magnetic field is applied, these small magnets are rearranged according to the magnetic force lines of the external magnetic field, and, more specifically, arranged in two directions that are parallel or antiparallel to the magnetic force lines of the external magnetic field. The above-mentioned direction parallel to the magnetic force lines of the external magnetic field is called a positive longitudinal axis, and the above-mentioned direction antiparallel to the magnetic force lines of the external magnetic field is called a negative longitudinal axis. The atomic nuclei only have a longitudinal magnetization component, and the longitudinal magnetization component has both direction and amplitude. Atomic nuclei in the external magnetic field are excited by a radio-frequency (RF) pulse with a specific frequency to make the spin axes of these atomic nuclei deviate from the positive longitudinal axis or the negative longitudinal axis to produce resonance. This is magnetic resonance. After the spin axes of the above-mentioned excited atomic nuclei deviate from the positive longitudinal axis or the negative longitudinal axis, the atomic nuclei will have a transverse magnetization component. After the radio-frequency pulse transmission has been stopped, the excited atomic nuclei transmit an echo signal and gradually release the absorbed energy in the form of electromagnetic waves, with the phase and energy level thereof both restoring to the state before being excited. An image may be reconstructed after the echo signal transmitted by the atomic nuclei is further processed by, for example, spatial encoding.
In the prior art, the magnetic resonance imaging system may operate with a number of various radio-frequency (RF) antennas (e.g., coils). The radio-frequency antennas are used for transmitting and receiving radio-frequency pulses so as to excite the atomic nuclei to radiate magnetic resonance signals and/or for acquiring the induced magnetic resonance signals. A magnetic resonance imaging (MRI) system includes various coils, such as a body coil covering the whole body area, a receiving coil only covering a certain part of the body and so on. The magnetic resonance system may have a large integrated coil (e.g., body coil) that is permanently fixed in a magnetic resonance scanner. The integrated coil may be arranged in a cylindrical manner surrounding a patient acquisition cavity (e.g., using a structure referred to as a birdcage structure), and in the patient acquisition cavity, a patient is supported on a bed (e.g., a patient positioning table) during measurement. Since the coverage area of the body coil is relatively large, a higher transmitting power is needed, and the signal-to-noise ratio of an obtained image is relatively low. The signal-to-noise ratio throughout the image is non-uniform as well. With respect to the body coil, the coverage area of a local coil is relatively small (e.g., the knee area covered by a knee coil, the head covered by a head coil, a wrist covered by a wrist coil), so the local coil receives only radio-frequency signals within a limited radio-frequency excitation range (in order to distinguish from the radio-frequency signals in the transmission stage, the radio-frequency signals received by the coil are hereinafter referred to as magnetic resonance signals). The signal-to-noise ratio of an obtained image is thus relatively high, and the signal-to-noise ratio throughout the image is relatively uniform.
The local coil is externally attached to the magnetic resonance imaging system. For existing magnetic resonance imaging systems, one interface may only support one local coil, and the number of interfaces configured by an early magnetic resonance system is relatively small. For an advanced application such as a later whole body image sweeping that uses a plurality of local coils simultaneously, this number of interfaces is apparently not enough. In order to make the magnetic resonance imaging system compatible with multiple local coils, a common practice is to increase the number of interfaces or to use control bus technology to send an upper-layer command to a decoder, so that the decoder controls a corresponding radio-frequency switch to switch according to the content of the command. The defects of the above method are the increase of costs of the magnetic resonance imaging system, and the original magnetic resonance imaging system that does not have enough interfaces will not be easily upgraded to a plurality of interfaces. The method that uses the control bus modifies software. The magnetic resonance imaging system has corresponding control lines and may introduce a clock signal that easily causes interference to the magnetic resonance imaging system.
The scope of the present invention is defined solely by the appended claims and is not affected to any degree by the statements within this summary.
The present embodiments may obviate one or more of the drawbacks or limitations in the related art. For example, an adapter that enables a magnetic resonance imaging system to increase the number of radio-frequency channels under the condition of not changing any hardware is provided. One interface is compatible with a plurality of coils. Without defining a complex communication protocol, the switching of the input signals of each coil may be realized by using the tuning/detuning signal currently possessed by an interface of the magnetic resonance imaging system.
The adapter provided by one or more of the present embodiments includes a control circuit, a control signal interface, a first input signal interface, a second input signal interface, and a first output signal interface. The control signal interface receives a tuning/detuning signal, and the control circuit switches, according to the tuning/detuning signal, the input signal interface and the second input signal interface to be in conduction with the first output signal interface.
In an implementation of one or more of the present embodiments, the adapter further includes a second output signal interface. The control circuit switches, according to the tuning/detuning signal, the first input signal interface and the second input signal interface to be in conduction with the first output signal interface and the second output signal interface.
In an implementation of one or more of the present embodiments, the control circuit includes a first diode, a second diode, a third diode, and a fourth diode. Cathodes of the first diode and the second diode are connected to the first input signal interface, and anodes of the third diode and the fourth diode are connected to the second input signal interface. An anode of the first diode and a cathode of the fourth diode are connected to the second output signal interface, and an anode of the second diode and a cathode of the third diode are connected to the control signal interface and the first output signal interface.
In an implementation of one or more of the present embodiments, the second output signal interface is grounded.
In an implementation of one or more of the present embodiments, the first diode, the second diode, the third diode, and the fourth diode are respectively connected in parallel with a protection circuit.
In an implementation of one or more of the present embodiments, the protection circuit includes a resistor and an inductor connected in series.
In an implementation of one or more of the present embodiments, the control circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode. Anodes of the first diode and the second diode are connected to the control signal interface. A cathode of the first diode, a cathode of the third diode and the first input signal interface are connected to an anode of the sixth diode. A cathode of the second diode, a cathode of the fourth diode and the second input signal interface are connected to an anode of the fifth diode. An anode of the third diode and a cathode of the fifth diode are connected to the first output signal interface. An anode of the fourth diode and a cathode of the sixth diode are connected to the second output signal interface.
The magnetic resonance imaging system provided by the embodiments includes any one of the above-mentioned adapters.
The coil provided by the embodiments includes any one of the above-mentioned adapters.
The magnetic resonance imaging system provided by the embodiments includes any one of the above-mentioned coils.
The embodiments enable the magnetic resonance imaging system to increase the number of radio-frequency channels under the condition of not changing any hardware, and one interface is compatible with a plurality of coils. Without defining a complicated communication protocol, the switching of the input signals of each coil may be realized by using the tuning/detuning signal currently possessed by an interface of the magnetic resonance imaging system itself, thereby substantially reducing the system structure and the replacement costs.
An adapter is provided. A tuning/detuning signal of a magnetic resonance imaging system is applied to control a radio-frequency switch. The adapter is controlled, via the radio-frequency switch, to realize accessing a plurality of coils to one connector simultaneously. The radio-frequency output of each coil of the plurality of coils, which are connected in a cascading manner, is switched via a switch, and the radio-frequency outputs are output to the system, so that the function of a multi-channel system may be realized on a system that has limited channels. Due to the use of an existing tuning/detuning signal, only the radio-frequency switch is to be integrated into the adapter or coil without any alterations to the original magnetic resonance imaging system.
Specific to the magnetic resonance imaging system, the adapter includes a radio-frequency signal output interface and two radio-frequency signal input interfaces. The radio-frequency signal output interface selects one of the two radio-frequency signal input interfaces through the tuning/detuning signal. When one of the radio-frequency signal input interfaces connects to the radio-frequency signal output interface, the other radio-frequency signal input interface connects to a 50 Ω resistor and is then grounded.
The second output signal interface GND is grounded, but the second output signal interface GND may also be connected to other components of the magnetic resonance imaging system so as to provide a corresponding output signal. The first diode V1, the second diode V2, the third diode V4, and the fourth diode V5 are respectively connected in parallel with a protection circuit. The protection circuit includes a resistor and an inductor connected in series.
From the perspective of operating principles, as shown in
Specific to the magnetic resonance imaging system, the adapter includes two radio-frequency signal output interfaces and two radio-frequency signal input interfaces. The two radio-frequency signal output interfaces select the two radio-frequency signal input interfaces through the tuning/detuning signal. When one of the radio-frequency signal input interfaces connects to one of the radio-frequency signal output interfaces, the other radio-frequency signal input interface connects to the other radio-frequency signal output interface.
From the perspective of operating principles, as shown in
One or more of the present embodiments enable the magnetic resonance imaging system to increase the number of radio-frequency channels under the condition of not changing any hardware, and one interface is compatible with a plurality of coils. Without defining a complicated communication protocol, the switching of the input signals of each coil may be realized by using the tuning/detuning signal currently possessed by an interface of the magnetic resonance imaging system, thereby substantially reducing the system structure and the replacement costs.
What are described above are merely embodiments of the present invention and are not intended to limit the protection scope of the present invention. During specific implementation, an appropriate improvement may be performed according to embodiments of the present invention, so as to adapt the specific requirements of specific situations. Therefore, it may be understood that the embodiments of the present invention as described herein are just used as demonstration, and are not intended to limit the protection scope of the present invention.
It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present invention. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims can, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.
While the present invention has been described above by reference to various embodiments, it should be understood that many changes and modifications can be made to the described embodiments. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201210555182.X | Dec 2012 | CN | national |
