Magnetic resonance imaging equipment

Abstract

To reduce the impact of interference in transmitting magnetic resonance data.SOLUTION: An MRI (magnetic resonance imaging) apparatus according to an embodiment includes a data collection unit, an encoding unit, and a data transmission line. The data collection unit generates MR data. The encoding unit digitally encodes the MR data so that a frequency component becomes a predetermined value or less at a Larmor frequency. The data transmission line transmits the digitally encoded MR data.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The embodiments disclosed herein and in the drawings relate to magnetic resonance imaging apparatus and methods of operation. [Background technology]

[0002] Magnetic resonance (MR) signals received by a radio frequency (RF) coil are typically transmitted to a magnetic resonance imaging (MRI) data acquisition system using coaxial cables for analog data transmission and fiber optic cables for digital data transmission. Analog data transmission requires baluns in the cables, which reduces operator usability and increases costs. Fiber optic cables used for digital data transmission also increase costs and may generate excessive heat due to the associated photoelectric conversion circuitry. Coaxial cables are not used for digital data transmission due to significant data artifacts caused by interference from the RF coil frequency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2015 / 0015256 [Patent Document 2] US Patent Application Publication No. 2019 / 0018089 [Patent Document 3] DE 2010 / 0329527 Summary of the Invention [Problem to be solved by the invention]

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to reduce the influence of interference when transmitting MR data. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0005] The MRI apparatus according to the embodiment includes a data acquisition unit, an encoding unit, and a data transmission line. The data acquisition unit generates MR data. The encoding unit digitally encodes the MR data so that the frequency components at the Larmor frequency are equal to or less than a predetermined value. The data transmission line transmits the digitally encoded MR data. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing the configuration of an MRI apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing the structure of a receiving circuit and an RF coil included in the MRI apparatus. [Diagram 3] FIG. 3 is a graph showing the power spectral density of a data stream. [Figure 4] FIG. 4 is a diagram of the MRI data acquisition and post-processing subsystems. [Diagram 5] FIG. 5 is a diagram of the tuning / matching circuit of FIG. [Figure 6] FIG. 6 is a circuit diagram of the notch filter according to this embodiment. [Figure 7] FIG. 7 is a graph showing the frequency response of the notch filter of FIG. [Figure 8] FIG. 8 is a circuit diagram of the notch filter according to this embodiment. [Figure 9] FIG. 9 shows a signal diagram of the MRI apparatus according to this embodiment and a corresponding eye pattern diagram. [Figure 10]FIG. 10 shows a signal diagram of a comparative example and a corresponding eye pattern diagram. [Figure 11] FIG. 11 is a block diagram of an embodiment deployed on a PC board with stripline or microstrip data transmission lines. [Figure 12] FIG. 12 is a block diagram of an embodiment in which stripline or microstrip data transmission lines and fiber optic converters are provided on a PC board. [Figure 13] FIG. 13 is a flow diagram of the operation method of the MRI apparatus according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] An embodiment will be described with reference to the drawings.

[0008] Fig. 1 is a diagram showing the configuration of an MRI apparatus according to the first embodiment. As shown in Fig. 1, the MRI apparatus 100 according to the first embodiment includes, for example, a static magnetic field magnet 101, a gradient magnetic field coil 103, a gradient magnetic field power supply 105, a bed 107, a bed control circuit 109, a transmission circuit 113, a transmission coil 115, a reception coil 117, a reception circuit 119, an imaging control circuit 121, an interface 123, a display 125, a storage device 127, and a processing circuit 129.

[0009] The static magnetic field magnet 101 is formed in a substantially cylindrical hollow shape. The static magnetic field magnet 101 generates a uniform static magnetic field in its internal space. A superconducting magnet may be adopted as the static magnetic field magnet 101. The static magnetic field magnet 101 may be formed in an open type.

[0010] The gradient magnetic field coil 103 is formed in a hollow cylindrical shape. Each gradient magnetic field coil 103 is disposed in the static magnetic field magnet 101. The gradient magnetic field coil 103 is configured by combining three coils corresponding to the mutually orthogonal X, Y, and Z axes. The Z-axis direction is the same as the direction of the static magnetic field. The Y-axis direction is the vertical direction, and the X-axis direction is the direction perpendicular to the Z and Y axes. Each of the three gradient magnetic field coils 103 receives power supply from a gradient magnetic field power supply 105, and each coil generates a gradient magnetic field, the magnetic field strength of which varies along the X, Y, and Z axes. Considering that the three coils are controlled by different channels, the gradient magnetic field coil 103 may be called a "gradient magnetic field coil having multiple channels."

[0011] The gradient magnetic fields generated by the gradient coil 103 in the X, Y, and Z axes may form a frequency encoding gradient magnetic field (also called a readout gradient magnetic field), a phase encoding gradient magnetic field, and a slice selection gradient magnetic field. The frequency encoding gradient magnetic field is used to change the frequency of the MR signal depending on the spatial location. The phase encoding gradient magnetic field is used to change the phase of the MR signal depending on the spatial location. The slice selection gradient magnetic field is used to determine the imaging plane.

[0012] The gradient magnetic field power supply 105 functions as a power supply device that supplies current to the gradient magnetic field coil 103 under the control of the imaging control circuit 121. The gradient magnetic field power supply 105 will be described in detail later.

[0013] The bed 107 is a device including a top board 107a on which the subject P lies. The bed 107 moves the top board 107a on which the subject P lies into a bore 111 under the control of a bed control circuit 109. The bed 107 may be installed in an examination room in which the MRI apparatus 100 is installed so that the longitudinal direction of the bed 107 is parallel to the central axis of the static magnetic field magnet 101.

[0014] The bed control circuit 109 controls the bed 107 and moves the tabletop 107a in the longitudinal and vertical directions by driving the bed 107 according to instructions input by the operator via the interface 123. Here, the bed control circuit 109 is an example of a means for realizing a bed control unit.

[0015] The transmission circuit 113 supplies an RF pulse corresponding to the Larmor frequency to the transmission coil 115 under the control of the imaging control circuit 121. The Larmor frequency in MRI refers to the precession speed of the magnetic moment of a proton subjected to an external magnetic field, and is, for example, 64 MHz or may be 128 MHz. Here, the transmission circuit 113 is an example of a means for realizing a transmission unit.

[0016] The transmitting coil 115 is an RF coil disposed inside the gradient magnetic field coil 103. The transmitting coil 115 receives an RF pulse from the transmitting circuit 113 and generates a transmitting RF wave corresponding to an RF magnetic field. The transmitting coil may be a whole body (WB) coil. The WB coil may be used as a transmitting / receiving coil.

[0017] The receiving coil 117 is an RF coil arranged inside the gradient magnetic field coil 103. The receiving coil 117 receives an MR signal emitted from the subject P under an RF magnetic field. The receiving coil 117 outputs the received MR signal to a receiving circuit 119. The receiving coil 117 may be a coil array having one or more coil elements, and may generally be a coil array having a plurality of coil elements. Although the transmitting coil 115 and the receiving coil 117 are illustrated as separate RF coils in FIG. 1, the transmitting coil 115 and the receiving coil 117 may be realized as an integrated transmitting / receiving coil. The transmitting / receiving coil may be arranged corresponding to an imaging target region of the subject P. For example, a head coil may be arranged as a local transmitting / receiving RF coil.

[0018] The receiving circuit 119 generates a digital MR signal, which is digitized complex data, based on the MR signal output from the receiving coil 117 under the control of the imaging control circuit 121. In particular, the receiving circuit 119 performs various signal processing on the MR signal output from the receiving coil 117, and then performs analog-to-digital (A / D) conversion on the data that has been subjected to the signal processing. The receiving circuit 119 samples the A / D converted data. In this manner, a digital MR signal (hereinafter, referred to as "MR data") is generated. The receiving circuit 119 outputs the generated MR data to the imaging control circuit 121. Here, the receiving circuit 119 is an example of a means for realizing a receiving unit.

[0019] The imaging control circuit 121 controls the gradient magnetic field power supply 105, the transmission circuit 113, and the reception circuit 119 according to the imaging protocol output from the processing circuit 129, and performs imaging of the subject P. The imaging protocol has various pulse sequences according to the examination. The imaging protocol may define, for example, a gradient magnetic field waveform indicating the magnitude of a current supplied from the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the timing at which a current is supplied from the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the magnitude of an RF pulse supplied from the transmission circuit 113 to the transmission coil 115, the timing at which an RF pulse is supplied from the transmission circuit 113 to the transmission coil 115, and the timing at which an MR signal is received by the reception coil 117. Here, the imaging control circuit 121 is an example of a means for realizing an imaging control unit.

[0020] The interface 123 includes a circuit for receiving various commands and information from an operator. The interface 123 may include, for example, a circuit related to a pointing device such as a mouse, or an input device such as a keyboard. The circuits included in the interface 123 are not limited to circuits related to physical operating parts such as a mouse and a keyboard. For example, the interface 123 may be provided with an electrical signal processing circuit that receives an electrical signal corresponding to an operation input from an external input device provided separately from the MRI apparatus 100 and outputs the received electrical signal to various other circuits.

[0021] The display 125 displays the MR images generated by the image generation function and various information related to imaging and image processing under the control of the system control function 129a of the processing circuitry 129. The display 125 may be a device such as a CRT display, a liquid crystal display, an organic electroluminescent display, an LED display, a plasma display, or any other display or monitor known in the art.

[0022] The storage device 127 stores MR data filled in the k-space using the image generating function 129b, and image data generated by the image generating function 129b. The storage device 127 also stores imaging conditions such as various imaging protocols and various imaging parameters that define the imaging protocols. The storage device 127 stores programs corresponding to various functions executed by the processing circuitry 129. The storage device 127 may be, for example, a semiconductor memory element such as a random access memory (RAM) or a flash memory, a hard disk drive, a solid state drive, or an optical disk. The storage device 127 may also be a drive device that reads and writes various information between a portable storage medium such as a CD-ROM drive, a DVD drive, or a flash memory. Here, the storage device 127 is an example of a means for realizing a storage unit.

[0023] The processing circuitry 129 includes a processor, a memory such as a ROM (Read Only Memory) and a RAM (RAM), and controls the MRI apparatus 100 as hardware resources, which are not shown. The processing circuitry 129 is provided with a system control function 129a and an image generation function 129b. Various functions executed by the system control function 129a and the image generation function 129b are stored in the storage device 127a in the form of a program executable by a computer. The processing circuitry 129 is a processor that can read out a program corresponding to each function from the storage device 127 and execute the program to realize the function corresponding to the program. In other words, the processing circuitry 129 in a state in which the program is read out is provided with the functions shown in FIG. 1 of the processing circuitry 129. Here, the processing circuitry 129 is an example of a means for realizing a processing unit.

[0024] 1 has been described as a structure in which various functions are realized by a single processing circuit 129, multiple independent processors may be combined to form the processing circuit 129, and functions may be realized by each processor executing a respective program. That is, the various functions described above may be prepared as a program implemented by a single processing circuit, or a specific function may be implemented by a dedicated independent program execution circuit.

[0025] The term "processor" may refer to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or a programmable logic device (e.g., SPLD (Simple Programmable Logic Device), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array)).

[0026] The processor realizes various functions by reading and executing the programs stored in the storage device 127. Instead of storing the programs in the storage device 127, the programs may be directly embedded in the circuitry of the processor. In this case, the processor realizes functions by reading and executing the programs embedded in the processor. Similarly, the bed control circuit 109, the transmission circuit 113, the reception circuit 119, and the imaging control circuit 121 are also configured by the above-mentioned processors or electronic circuits.

[0027] The processing circuitry 129 controls the MRI apparatus 100 using the system control function 129a. Specifically, the processing circuitry 129 reads out a system control program stored in the storage device 127, expands it on the memory, and controls each circuit of the MRI apparatus 100 according to the expanded system control program. The processing circuitry 129 may read out an imaging protocol from the storage device 127 using the system control function 129a based on imaging conditions input by an operator to the interface 123. The processing circuitry 129 may generate an imaging protocol based on the imaging conditions. The processing circuitry 129 transmits the imaging protocol to the imaging control circuitry 121 and controls imaging of the subject P. Here, the processing circuitry 129 that executes the system control function 129a is an example of a means for realizing a system control unit.

[0028] The processing circuitry 129 uses the image generation function 129b to store the MR data in the readout direction of the k-space according to the strength of the readout gradient magnetic field. The processing circuitry 129 generates an MR image by performing a Fourier transform on the MR data stored in the k-space. The processing circuitry 129 outputs the MR image to the display 125 and the storage device 127. Here, the processing circuitry 129 that executes the image generation function 129b is an example of a means for realizing an image generation unit.

[0029] The overall structure of the MRI apparatus 100 according to the first embodiment has been described above. Next, the structures of the receiving circuit 119 and the RF coil will be described with reference to FIG. 2. The coil element 201 generates an analog data signal during MRI operation. The analog data signal is sent to the analog / digital signal processing system 200 and converted into digitized data (MR data) by the analog / digitalization subsystem 202. The digitized data is digitally encoded by the line serializer / encoder 203. The line serializer / encoder 203 generates digitally encoded data in the form of a SERDES (SERializer / DESerializer) data stream 204 having a period τ. The SERDES data stream is input to a notch filter 205 centered on a frequency corresponding to τ. The SERDES data stream that has passed through the notch filter is transmitted via a data transmission line (transmission medium) 206. The data transmission line 206 may be an intracoil medium or a coil system medium. Here, the analog / digitalization subsystem 202 is an example of a data acquisition unit. The line serializer / encoder 203 is an example of an encoding unit, and the notch filter 205 is an example of a filter unit.

[0030] As shown in FIG. 2, the SERDES data stream is digitally encoded to have a period τ, where if τ is selected to correspond to the Larmor frequency, the spectral content at the Larmor frequency is minimized. FIG. 3 shows the power spectral density of the SERDES data stream as a function of frequency. The power spectral density has null values ​​at multiples of τ, where null values ​​mean zero. Because the data content of the SERDES data stream is essentially zero at frequencies equal to multiples of τ, interference at frequencies equal to multiples of τ does not significantly affect the SERDES data stream. By selecting τ to be equal to the Larmor frequency, noise artifacts at the Larmor frequency from RF coils on subsequent data transmission lines, such as coaxial cables, can be minimized.

[0031] Schematically illustrates a notch filter 300. The notch filter has a desired attenuation in a desired bandwidth centered at a frequency τ. For example, the attenuation may be −3 dB or less in a bandwidth equal to the imaging band (e.g., 1 MHz).

[0032] FIG. 4 shows the analog / digital signal processing system 200 in more detail. The coil element 201 of the RF coil has coil element loops 201-0 to 201-n, where n can range, for example, from 1 to 128, and typically ranges from 8 to 32. The coil element loops 201-0 to 201-n correspond to data channels CH0 to CHn, respectively, of the analog / digital subsystem 202. Each channel of the analog / digital subsystem 202 carries an analog data signal from the RF coil and has a set of circuits that convert the analog data signal to a digital signal. For example, the data channel CH0 includes a tuning / matching circuit 207-0 as illustrated in FIG. 5.

[0033] The tuning / matching circuit 207-0 has a balanced tuning circuit 221 and a matching circuit 222 connected to the coil element 201, followed by a discrete balun 223 that converts the balanced configuration to a single-ended transmission line. A phase shifter 224 converts the input impedance of the preamplifier to a high impedance seen by the coil. To provide a suitable impedance, the phase shifter 224 may be replaced by a coaxial cable, microstrip or stripline. The output of the phase shifter 224 (or one end of the cable, microstrip or stripline) is connected to a low noise amplifier (LNA) 225.

[0034] More specifically, tuning circuit 221 is preferably a pair of series connected capacitors placed across the differential lines with the node between the capacitors grounded. Matching circuit 222 is preferably a pair of inductors placed on each differential transmission line. Balun 223 is a pair of LC circuits placed on each differential transmission line. Phase shifter 224 is an LC circuit that provides a desired impedance.

[0035] The data channel CH0 also has an amplifier circuit having a structure of two LNAs 208-0 and 209-0 separated by an attenuator 210-0 consisting of a variable resistor for gain adjustment, for example. The two LNAs are generally different, with the LNA closer to the coil having a lower noise value and an input impedance suitable for the coil interface. The amplified data signal is sent to a bandpass filter 211-0 designed for the imaging band. For example, the bandpass filter has a flat response in the imaging band. The signal output from the bandpass filter 211-0 is converted into a digital data signal by an ADC (Analog-to-Digital Converter) 212-0. Typically, this data signal contains 16 bits.

[0036] The digital data signals from the ADCs 212-0 to 212-n are digitally encoded in the modulator 213. The modulator 213 is an example of the line serializer / encoder 203. The modulator 213 encodes the digital data signals from the ADCs 212-0 to 212-n using a standard DC-balanced limited run-length technique, such as 8B / 10B encoding, to generate two SERDES data streams of 10 bits each from the 16-bit data. The run-length may be limited to, for example, 5 symbols. The 8B / 10B decoding function may be provided using a discrete chipset, such as a Cypress CY7B923 / CY7B933 HOTLink® transceiver, or as part of a multi-function chipset.

[0037] The SERDES data stream output by modulator 213 is sent to a notch filter 214. Notch filter 214 is a filter that eliminates a band centered around a null frequency, preferably the Larmor frequency (64 MHz), to further reduce frequency content in the SERDES data stream. Because notch filter 214 is tuned to the null frequency, the SERDES data stream can be transmitted to downstream components without loss of data signal fidelity.

[0038] An example of a notch filter 214 is shown in FIG. 6. The notch filter 214 has a differential transmission line structure that blocks common mode currents on the transmission line, eliminating the need for a balun on the transmission line. Typical values ​​for the parallel LC circuit are 6.22 nH and 994.72 pF. A series-connected LC circuit with a 2486.8 nH inductor and a 2.49 pF capacitor is placed between the pair of parallel LC circuits. These typical values ​​are examples, and other values ​​that provide the desired notch frequency response are possible. This filter can be used with Low-Voltage Differential Signal (LVDS) data transmission lines.

[0039] 7 shows the frequency response of notch filter 214. Notch filter 214 provides -60 dB attenuation at approximately the Larmor frequency. Other attenuation values ​​may be selected that provide sufficient suppression of frequency components at the Larmor frequency. Notch filter 214 preferably has -3 dB attenuation over a bandwidth of approximately 1 MHz centered at approximately the Larmor frequency.

[0040] FIG. 7 shows the return loss M11 and the insertion loss M21. The return loss indicates how much energy is reflected back by the filter. The insertion loss indicates the energy that passes through the filter. The filter in FIG. 7 is preferably a band-reject (notch) filter that rejects the band at the imaging frequency (approximately 64 MHz, or frequencies in a 1.5T system). The filter in FIG. 7 rejects frequencies in the SERDES data stream (approximately 64 MHz in a 1.5T system) that may interfere with the MR signal from the patient / object.

[0041] Another example of a notch filter is shown in Figure 8. This filter is intended for use with LVDS.

[0042] Eye diagrams are useful in illustrating the fidelity of signal transmission. Figures 9(a) and 9(b) show signal diagrams and corresponding eye diagrams according to the present embodiment. The signal diagram and eye diagram show the case where encoding is selected for τ=64 MHz and includes a notch filter (shown diagrammatically) centered at 64 MHz. Figures 10(a) and 10(b) show a comparative example in which the notch filter is centered at approximately 64 MHz and τ=320 MHz. The eye diagram in Figure 9(b) clearly shows that the present embodiment can reduce distortion and timing errors, as the eye pattern is wider and more open, and the voltage deviation is narrower. In particular, Figures 9(b) and 10(b) show how a notch filter centered at the Larmor frequency can eliminate potential electromagnetic interference at imaging frequencies while preserving the integrity of the SERDES data stream. As shown in Figures 10(a) and (b), the Larmor frequency notch filter removes spectral components from the SERDES data stream, causing the eye pattern to become smaller (the smaller the eye pattern, the lower the signal integrity).

[0043] Returning to Figure 4, the data signal that passes through notch filter 214 is typically sent to connector 215 for transmission over data transmission line 216. In the example of Figure 2, data transmission line 216 is further connected via connector 215 to a downstream subsystem 217 for data analysis using data processor 218.

[0044] The data transmission line 216 is an electronic data transmission line. In one example, the data transmission line 216 is a coaxial cable to eliminate or substantially reduce interference at the Larmor frequency. A coaxial cable can be used when the downstream subsystem 217 is remote from the analog / digital signal processing system 200 or is connected to a different subsystem. If the distance is long, a balun or an additional notch filter can be placed on the cable. The additional notch filter can be of the same structure as the notch filter 214 or of a different structure than the notch filter centered at approximately 64 MHz.

[0045] The data transmission line 216 may be an LVDS communication line, which accepts digitally encoded data, preferably in an 8B / 10B encoding format, and is effective at filtering common mode noise. The notch filter 214 is advantageously used in conjunction with the LVDS communication line.

[0046] FIG. 11 shows another example in which the data transmission line 216 is a stripline or a microstrip. In an MRI apparatus, an FPGA data acquisition chip (FPGA data collector) 302 is connected to an ADC chip 300 operating as a modulator / encoder on a PC board 304 via a stripline or microstrip transmission line 301. In order to further reduce noise components, a notch filter 303 centered approximately at the Larmor frequency may be used. Here, the ADC chip 300 is an example of an encoding unit. Also, the notch filter 303 is an example of a filter unit. Also, the FPGA data acquisition chip 302 is an example of a data acquisition circuit.

[0047] A third example is shown in Figure 12. A data transmission line 401 connects a modulator 400 to a fiber optic converter / connector 402 that converts the data signal into a fiber optic signal for transmission as an optical signal. A notch filter 403 may also be used in this example. Also in this example, the data transmission line 401 is a stripline or microstrip on a PC board 404. Here, the modulator 400 is an example of an encoding section. Also, the notch filter 403 is an example of a filter section.

[0048] The MRI apparatus according to the present embodiment has several advantages. The first advantage, and the most important advantage, is that electronic data transmission can be realized between circuits or subsystems within the MRI apparatus. The second advantage is that the MRI apparatus according to the present embodiment can significantly reduce the influence of the operating frequency of the MRI, thereby reducing the amount of shielding required and therefore reducing costs.

[0049] Another advantage is that the cost and weight of the RF coil and the RF coil interface cable are reduced, and the reduced weight improves maneuverability. Conventional coils and interface cables have large and heavy baluns, but the MRI apparatus according to the present embodiment can eliminate the baluns or reduce the number of baluns.

[0050] An additional benefit is that heat generation is reduced by eliminating the fiber optic connections traditionally used for electronic data transmission in MRI systems, which is particularly useful when fiber optic connectors are located close to the patient and where heat generated by fiber optic connections complicates operation by limiting temperature operating limits or approaching patient safety limits.

[0051] FIG. 13 illustrates an embodiment of a method of operating an MRI device. In step 500, MRI data is generated in the MRI device. In one example, a data signal is generated by an RF coil. The MRI device operates at the Larmor frequency, i.e., 64 MHz. In step 501, the data signal is digitally encoded using a standard DC-balanced, limited run-length technique, e.g., 8B / 10B encoding, to generate a data stream, e.g., a SERDES data stream. The frequency of the encoding nulls is set to approximately the Larmor frequency of 64 MHz.

[0052] In step 502, the digitally encoded data is filtered with a notch filter centered about the Larmor frequency to further remove frequency components at about the Larmor frequency. In step 503, the filtered data is transmitted over an electronic data transmission line, which may be a coaxial cable, a stripline, or a microstrip conductor.

[0053] According to at least one of the embodiments described above, it is possible to reduce the influence of interference when transmitting MR data.

[0054] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0055] 100 MRI machine 202 Analog / Digital Subsystem (Data Acquisition Section) 203 Line serializer / encoder (encoding section) 205 Notch filter (filter part) 206,216 Data transmission lines 217 Back-end Subsystem 300 ADC chip (encoder section) 302 FPGA data acquisition chip (data acquisition circuit) 303 Notch filter (filter part) 400 Modulator (Encoder) 401 Data Transmission Line 402 Fiber optic converter / connector (fiber optic conversion circuit) 403 Notch filter (filter part)

Claims

1. A plurality of receiving coils for detecting magnetic resonance signals generated from a subject; A plurality of AD conversion units for converting the magnetic resonance signal as an analog signal into a digital signal, the plurality of AD conversion units being provided corresponding to different receiving coils among the plurality of receiving coils; an encoding unit that converts the plurality of digital signals outputted as parallel signals from the plurality of AD conversion units into a serial signal; a data transmission line for transmitting the serial signal output from the encoding unit; Equipped with A magnetic resonance imaging apparatus, characterized in that a period of the data stream in the encoding section corresponds to a Larmor frequency that generates the magnetic resonance signal from the subject.

2. 2. The magnetic resonance imaging apparatus according to claim 1, wherein the data transmission line includes at least one of a coaxial cable, a stripline, and an LVDS (Low-Voltage Differential Signal) line.

3. The magnetic resonance imaging apparatus includes a filter unit that attenuates signals in a predetermined frequency band including the Larmor frequency among signals included in the serial signal output from the encoding unit, 3. The magnetic resonance imaging apparatus according to claim 1, wherein the data transmission line transmits a signal output from the filter section.

4. 4. The magnetic resonance imaging apparatus according to claim 1, wherein the encoding unit performs the conversion using an 8B / 10B encoding method.

5. The magnetic resonance imaging apparatus of any one of claims 1 to 4, characterized in that it is provided with a downstream subsystem that analyzes the serial signal transmitted via the data transmission line.

6. A magnetic resonance imaging apparatus as described in any one of claims 1 to 5, characterized in that the period of the data stream is set so that the spectral components of the data stream are minimum at the Larmor frequency.

Images