阅读说明：本技术 用于对rf线圈进行质量分析的方法和磁共振成像设备 (For carrying out the method and MR imaging apparatus of quality analysis to RF coil ) 是由 P.穆利希 A.波特哈斯特 于 2019-05-13 设计创作，主要内容包括：本发明涉及一种用于对RF线圈进行质量分析的方法和磁共振成像设备。本发明涉及一种用于对磁共振成像设备(1)的RF线圈(3)进行质量分析(QA)的方法,其中,在工作模式下,RF线圈(3)被设计为用于从要观察的对象获取MR信号,所述方法在测试模式下包括：-由RF发射器(5)发射测试信号(20),-由RF线圈(3)直接接收来自RF发射器(5)的测试信号(20),其中,RF线圈(3)提供输出信号(21),以及-通过分析RF线圈(3)的输出信号(21)提供性能指示(11),以进行质量分析。(The present invention relates to a kind of for carrying out the method and MR imaging apparatus of quality analysis to RF coil.The present invention relates to a kind of methods that the RF coil (3) for MR imaging apparatus (1) carries out quality analysis (QA), wherein, in the operational mode, RF coil (3) be designed to be used as from will from object acquisition MR signal, the method includes: in test mode-emit test signal (20) by RF transmitter (5), the test signal (20) from RF transmitter (5) is directly received by RF coil (3), wherein, RF coil (3) provides output signal (21), and-output signal (21) offer Performance figure (11) of analysis RF coil (3) is provided, to carry out quality analysis.)

1. the method that one kind carries out quality analysis (QA) for the RF coil (3) to MR imaging apparatus (1), wherein in work Under operation mode, RF coil (3) be designed to be used as from will from object acquisition MR signal, the method wraps in test mode It includes:

Emit test signal (20) by RF transmitter (5),

The test signal (20) from RF transmitter (5) is directly received by RF coil (3), wherein RF coil (3) provides output Signal (21), and

Performance figure (11) are provided by the output signal (21) of analysis RF coil (3), to carry out quality analysis.

2. according to the method described in claim 1, wherein, by output signal (21) and/or Performance figure (11) and reference value (22) it is compared.

3. according to the method described in claim 2, wherein, reference value (22) corresponds to

Based on the value of the measurement during Medical Resonance imaging device (1) initialization, and/or

A reference value.

4. method according to any one of the preceding claims, wherein in order to provide Performance figure (21), detection output letter The temporal correlation of the amplitude of the amplitude and/or output signal (21) of number (21).

5. method according to any one of the preceding claims, wherein test signal (20) includes several frequencies or sweeps Frequently.

6. method according to any one of the preceding claims, wherein MR imaging apparatus (1) includes hole (2), In, in test mode, object, MR sample and/or the model that hole (2) not observed.

7. method according to any one of the preceding claims, wherein during receiving test signal (20), make RF coil (3) it tunes and/or detuning.

8. method according to any one of the preceding claims, wherein during receiving test signal (20), activate medicine The other component of resonance image-forming equipment (1), such as amplifier (4) and/or gradient coil (8).

9. method according to any one of the preceding claims, wherein several RF coils (3) are arranged in hole (2), In, each RF coil (3) receives the test signal (20) for coming from RF transmitter (5), wherein RF coil provides output signal respectively (21), and

Performance figure (11) are provided by the output signal (21) of analysis RF coil (3), to carry out quality analysis.

10. method according to any one of the preceding claims, wherein test signal (20) include with ramp shaped or The RF pulse of person's rectangular shape.

11. method according to any one of the preceding claims, wherein by RF coil (3) and another RF receiver (13) test signal (20) is received, in addition with the output signal (21) for comparing RF coil and another described RF receiver (13) Output signal (23).

12. method according to any one of the preceding claims, wherein RF transmitter (5) is MR imaging apparatus (1) Body coil or additional RF transmitter.

13. it is a kind of for RF coil carry out quality analysis equipment, wherein the equipment include RF transmitter, processor and RF coil, wherein the equipment is configurable for

Emit test signal (20) by RF transmitter (5),

The test signal (20) from RF transmitter (5) is directly received by RF coil (3), wherein RF coil provides output signal (21), and

Performance figure (11) are provided by the output signal (21) of analysis RF coil (3), to carry out quality analysis.

14. a kind of computer program product, for when computer program product is loaded into the memory of programmable device, The step of executing method according to any one of claim 1 to 12.

15. a kind of computer-readable medium is stored thereon with the program element that computer unit can read and execute, so as to When the computer unit executes described program element, method according to any one of claim 1 to 12 is executed Step.

Technical field

The present invention relates to a kind of for carrying out the method and MR imaging apparatus of quality analysis to RF coil.

Background technique

MR imaging apparatus, particularly magnetic resonance tomography (MRI) scanner are commonly known in the art, and It and is powerful for understanding the internal structure of object, particularly patient in depth.In mri, patient is usually transported to In the hole of magnet, and at the interested region that will be scanned or it is disposed about local RF coil.In the operational mode, RF transmitter is usually body coil transmitting excitation RF signal, and RF Coil Detector comes from object in response to excitation RF signal Magnetic resonance signal.Acquired data are collected and rebuild, the internal structure of patient is visualized.US9360541B2, US9194924B2, US20170089991A1 and US8190237B2 disclose the local coil of several types.

In order to ensure operating reliability and picture quality in clinical magnetic resonance imaging (MRI) measurement, regular quality is carried out Guarantee (QA) measurement.In particular, these QA measurements concentrate in local coil characteristic.In the feelings of current MR imaging apparatus Under condition, software tool is provided to check the quality of RF coil.This local coil QA process usually requires operator for local RF Coil and suitable MR model (phantom) are located in hole together.For big coil, that is, have than MRI scanner The coil of the big spatial dimension of visual field, it is necessary to which multiple such model settings are continuously provided.

When QA process starts, one or more MR measurement is carried out.Then, for general picture characteristics, such as Brightness and/or signal-to-noise ratio analyze the two-dimensional image data of the data reconstruction obtained according to acquired in.Due to current Local coil generally there are multiple coil parts, therefore to the generated data from all coils element and come from each member Both data of part are analyzed.Finally, reference value or reference inspection relative to standard parameter predetermined appropriate The result of these assessments.This inspection offer local coil QA process passes through/fail criteria.

Summary of the invention

The technical problem to be solved by the present invention is to improve, particularly simplify the process to the progress QA measurement of RF coil.

Above-mentioned technical problem by it is according to the present invention to MR imaging apparatus carry out quality analysis method and according to MR imaging apparatus of the invention solves.

According to the first aspect of the invention, a kind of RF coil progress quality analysis for MR imaging apparatus is provided Method, wherein in the operational mode, RF coil be designed to from will from object acquisition MR signal, wherein test mould Following steps are executed under formula:

- RF transmitter transmitting test signal,

- RF coil directly receives the test signal from RF transmitter, wherein and RF coil provides output signal, and

It is analyzed by the output signal to RF coil to provide Performance figure, to carry out quality analysis.

In contrast to the prior art, RF coil directly detects the test signal provided by RF transmitter.Therefore, mould is not both needed Type body does not need MR sample (probe) yet, and does not need to place it in hole.Therefore, QA process is simplified, because Can be omitted step MR model being arranged in hole.In particular, not needing to determine MR model relative to RF coil To guarantee the reproducibility of QA analysis.In addition, QA process can carry out automatically, and the timing of QA process and MR sample Availability is unrelated (such as when several MR imaging apparatus share common MR model).Another advantage is not need Two dimension or 3-D image of reconstruction including time-consuming imaging sequence and MR signal, MR model.It replaces, use is defeated The initial data that signal, i.e. RF coil itself provides out, to identify the modification and/or defect of RF coil.Therefore, and in QA process The middle method using MR model and by MR model volume visualization to identify defect is compared, and the effort for carrying out QA analysis significantly subtracts It is few, and especially carry out faster.

In test mode, RF transmitter, the body coil transmitting of preferably MR imaging apparatus or injection test letter Number, test signal at least has the amplitude similar with the general amplitude of the response signal detected in the operational mode.RF coil, Especially local coil, such as surface coils or birdcage coil directly receive these test signals.It is even conceivable that RF line Circle is body coil, in this case, RF transmitter not instead of body coil, additional RF transmitter.Term " direct " It means in test mode, the signal of receiver detection transmitting, the response signal without detecting MR model or patient's transmitting. Output signal is the electric signal with amplitude and specific and/or temporal correlation.The form of output signal preferably has with test signal It closes.Due to the processing carried out by RF coil and its electronic equipment, state of the output signal also with RF coil, particularly RF coil has It closes.Therefore, variation or modification can be identified by using known test signal.It is preferred that signal normalization will be tested, make Obtain the modification or defect of the variation instruction RF coil of output signal.In other words: RF coil picks up test signal, generates output letter Number, and the output signal for identical test signal or at least similar test signal is compared.

Term " Performance figure " is general for the parameter of the current Quality suitable for assessment magnetic resonance equipment.It is this The example of Performance figure is noise figure, snr value, the Noise Correlation between different single coil elements and spike electricity It is flat.It is preferred that identified Performance figure is compared with reference value, especially it is compared automatically, and for example pass through MRI Equipment sends warning signal come the state for notifying operator's RF coil current.When Performance figure is more than or is lower than threshold value, Caution signal can be provided.It is preferred that by the processor offer property for being configurable for analyzing the data obtained from RF coil It can instruction.For example, processor is merged into the work station or console of (individual) computer, such as medical imaging devices. Preferred processor is a part of MRI machine.It is also contemplated that processor is located at the server of network or cloud, and online It is analyzed.Further, it is contemplated that Performance figure is stored in storage equipment.Therefore, it can be advantageous to which observation is about performance The trend of instruction.In particular, between quality analysis or QA process are or carrying out, particularly the quality that carries out at regular intervals is protected Card measurement.It is even conceivable that in the case where no operator, for example execute this method at night because do not need into The movement of one step.Alternatively, immediately in operation for diagnosing image or spectrum test method (spectroscopy) medicine at As equipment executes this method later and/or before.

For example, can by extract output signal maximum amplitude and generate RF coil output signal test signal it Preceding and/or specific time later amplitude determines signal-to-noise ratio.Then, can by formed the relationship of described two amplitudes come Determine signal-to-noise ratio (SNR).It is also contemplated that the temporal correlation of record output signal, and handled by Fourier transform The signal recorded, to obtain the spectral characteristic of RF coil.It is preferred that changing the frequency of variable test signal when recording output signal.In In this case, Performance figure can be by frequency spectrum designation.It is also contemplated that test signal includes several pulses or pulse sequence Column, to improve measurement accuracy.

It is set as according to preferred embodiment, output signal and/or Performance figure is compared with reference value.Therefore, may be used To identify variation or difference relative to reference signal.The difference of preferred properties instruction/between output signal and reference value can be with It is no more than or is lower than threshold value, guarantees the normal function of RF coil.It is preferred that providing magnetic when being more than or lower than the threshold value The caution signal of resonant device.

It is especially arranged to, reference value corresponds to

Based on the value of the measurement during the initialization of Medical Resonance imaging device, and/or

A reference value, for example, at the corresponding database obtained by a reference value.For example, reference value corresponded in the installation phase Between the Performance figure that is extracted from measurement by using MR sample or model.In other words, the QA mistake using MR sample is carried out Journey, to provide reference value.Then, QA analysis is carried out to RF coil in the case where no MR model or MR sample.Replacement Ground, it is envisioned that the general standard of specific RF coil or a reference value are used as reference value.

It is preferred that the temporal correlation of the amplitude of the amplitude and/or output signal of measurement output signal, to provide Performance figure. Especially it is possible to using the temporal correlation of output signal, it is special with the frequency spectrum for providing RF coil by carrying out Fourier transform Property.It is also contemplated that only extracting maximum amplitude and/or the amplitude of time predetermined from output signal.

It is set as in another embodiment of the present invention, RF coil is located in predetermined position.It therefore, can be with Easily reproduce the condition having been carried out in the previous measurement of output signal in response to test signal.It is preferred that RF coil is placed Specific location in the hole of MR imaging apparatus.It is also contemplated that executing the side outside MR imaging apparatus Method, because local RF coil can be separated with MR imaging apparatus.In this case, additional external RF also can be used Transmitter.

It is set as in another embodiment, test signal includes several frequencies or frequency sweep (frequency sweep). Therefore, it can analyze reaction of the output signal to different frequencies, and can identify the response line for being suitable as Performance figure The reaction of the frequency dependence of circle.

It is set as according to another embodiment of the invention, MR imaging apparatus includes hole, wherein in test pattern Under, object, MR sample and/or model that hole not observed.Therefore, it can be advantageous to not by object, MR sample and/or Model carries out QA process in the case where being placed in hole.Especially it is possible to which several coils are arranged in hole using available space.

It is set as in useful embodiment, during receiving and testing signal, makes RF coil tuning and/or detuning.Therefore, It can produce output signal to respond the another of test signal.The response may be used as another Performance figure.Such as it is arranged The resonant frequency of RF coil to be shifted or changing during receiving test signal, so that resonant frequency is between the time of definition It is matched and detuning every interior with the frequency of test signal, particularly carrier frequency.As a result, the case where with not detuning/tuning It compares, output signal reduces, because frequency of the resonant frequency of RF coil at least temporarily with test signal mismatches.In addition, In The output signal detected under the conditions of described allows to extract other spectral characteristic.It is also contemplated that for about the time It is spaced different several different tunings/detuning event detection output signals, wherein resonant frequency receives survey with about RF coil The beginning of the time interval of the time of trial signal and/or the carrier frequency matching for testing signal.It is preferred that receiving the output signal phase Between generate tuning/detuning event.Then, to the assessment of the time course of output signal permit a determination that the tuning of RF coil/ The detuning switching time between detuning/tuning.

It is set as in another embodiment of the present invention, activates Medical Resonance imaging device during receiving test signal Other component, such as amplifier and/or gradient coil.Therefore, it can be advantageous to the property of identification and MR imaging apparatus It can relevant other Performance figure.For example, different gradient pulses can be generated in cycle tests, wherein gradient pulse Length and/or amplitude it is different.These gradient pulses are preferably generated by gradient coil.Therefore, it can identify that high exception is defeated Signal out generally will lead to spike artifact when visualizing medical image in the operational mode.Furthermore, it is possible to simulate in addition in work Existing physical condition during operation mode.For example, RF coil receive test signal during or before activate amplifier.It is logical Often, common in the operational mode " interference " can be simulated, to observe RF coil in response to the reaction of interference.

It is preferably arranged to, several RF coils is arranged in hole, wherein each RF coil receives the survey from RF transmitter Trial signal, wherein RF coil provides output signal respectively, and

Performance figure is provided by analyzing the output signal of RF coil, to carry out quality analysis.It is preferred that coil phase each other It arranges and/or is connected to each other adjacently.Therefore, it can be advantageous to while quality analysis is carried out to several RF coils.It is preferably arranged to, RF coil is arranged and is connected to each other in a predefined manner, to guarantee reproducible condition.

It is set as in another embodiment of the present invention, test signal includes having ramp shaped or rectangular shape RF pulse.By the shape for modifying pulse, thus it is possible to vary the output signal of the response as test signal.As a result, it is possible to Different Performance figures is provided according to the shape of test signal.

It is set as according to another embodiment of the invention, test signal is received by RF coil and another RF receiver, To compare the output signal of RF coil and the output signal of another RF receiver.Especially it is possible to use another RF Receiver is as the additional reference for controlling test signal.Also another RF receiver can be used and carry out compensating test signal Signal to signal fluctuation.This improves the accuracy of determining Performance figure.In addition it is possible to use another RF receiver, To guarantee to carry out quality analysis using standardized test signal.Another RF receiver, which can be, is able to detect RF signal Another sensor or another coil.It is preferred that another receiver is a part of MRI machine.

It is set as according to another embodiment of the invention, the amplitude for testing signal is less than the work used in the operational mode Make the amplitude of signal, wherein the signal amplitude for testing signal is preferably 100-10000 times smaller than working signal, especially than specific The achievable maximum functional signal of MR imaging apparatus is 10000 times small.Therefore, test signal is avoided to damage RF coil.It is special It is not the saturation for considering preamplifier, to select the amplitude of test signal.For example, the preamplifier of local coil has The maximum input level of about -30dB, and the transmission between body coil and local coil is about -40dB, so that preposition amplification Device is unsaturated.The maximum amplitude of the signal, i.e. maximum functional signal that are emitted by the body coil of 3 tesla's systems is typically about 75dB.For some additional safeties, test signal can be reduced into 80dB, this corresponds to 10000 times.But usually work Signal is less than peak swing.As a result, it is assumed that small 100 to 10000 times of Amplitude Ration working signal for testing signal are reasonable. In particular, it is contemplated that the variation of working signal is very big, and may have 10V (2W, 33dB) and 1000V (20kW, Value between 73dB).

Be set as in another embodiment of the present invention, RF transmitter be MR imaging apparatus body coil or Additional RF transmitter.

It is preferred that RF transmitter and RF coil are a part of MR imaging apparatus.For example, RF transmitter is configured as, make It obtains RF transmitter and emits working signal in the operational mode, and transmitting test signal in test mode.It therefore, can be advantageous Ground emits both working signal and test signal using body coil.

Alternatively, RF transmitter, which can be, for example sends out the additional RF that MR imaging apparatus adds for test pattern Emitter, and RF transmitter is only configured to for emitting test signal.Additional RF transmitter can be located in magnetic resonance External coil in the magnet bore of imaging device.This additional RF transmitter is for cannot easily be switched to test pattern The upgrading of system can be reasonably.In addition, this additional RF transmitter has the advantages that and it can be used, to body Body coil carries out QA.

Another theme of the invention is the MR imaging apparatus for carrying out quality analysis to RF coil, wherein magnetic Resonance image-forming equipment includes RF transmitter, wherein MR imaging apparatus is configurable for

Test signal is emitted by RF transmitter,

- RF coil directly receives the test signal from RF transmitter, wherein and RF coil provides output signal, and

Performance figure is provided by analyzing the output signal of RF coil, to carry out quality analysis.

It can be diverted to MR imaging apparatus for all features of the method description, vice versa.

Another aspect of the present invention is computer program product, for programmable when computer program product to be loaded into When in the memory of equipment, the step of execution according to the method for the present invention.

Another aspect of the present invention is computer-readable medium, and being stored thereon with computer unit can read and hold Capable program element, so as to computer unit execute described program element when, execute according to the method for the present invention the step of.

Detailed description of the invention

In attached drawing:

Fig. 1 shows the block diagram of method of the explanation for carrying out quality analysis to magnetic imaging equipment.

Specific embodiment

Block diagram is shown in FIG. 1, wherein block diagram show for the RF coil provided for MR imaging apparatus into The method of row quality-assurance processes, i.e. quality analysis QA.MR imaging apparatus 1, such as magnetic resonance tomography equipment, are logical Cross the powerful that different tissue visualizations is for example understood in depth to the internal structure of patient.Magnetic imaging equipment 1 include by The hole 2 of magnet formation, RF transmitter 5, such as body coil and RF coil 3.It in the operational mode, such as will by using platform 4 Patient is arranged in hole 2.In particular, RF coil 3 forms RF coil and is positioned at the area-of-interest of patient or attached Closely, so as to by the internal structure of patient visualize.In order to obtain data, RF transmitter 5 emits working signal, working signal excitation The molecule of patient's body.Due to this excitation, the tissue emissions signal to be observed, wherein the signal emitted is again by RF coil 3 It receives.Then, the internal structure of patient is visualized using acquired data.

However, the constant mass in order to guarantee visual image, it is necessary to carry out surveying about the function of RF coil 3 every now and then Examination.This quality-assurance processes need that RF coil 3 and corresponding MR model or sample are manually positioned at magnetic imaging and are set In standby 1 hole 2.Then, several MR measurements are carried out, with recognition performance instruction 11, such as brightness value and/or signal-to-noise ratio.It can incite somebody to action These identified Performance figures 11 are compared with reference value 22, such as a reference value, to check to MR imaging apparatus 1 Quality analysis QA failure still passes through.

In order to simplify and accelerate the process of the quality analysis QA about magnetic imaging equipment 1, in the test of magnetic imaging equipment 1 Or under analytical model, by RF transmitter 5, preferably by the RF transmitter 5 of MR imaging apparatus 1, such as body coil, transmitting Test signal 20.The test signal 20 of RF transmitter 5 is configured as so that test signal 20 have with generally by RF model/ The similar amplitude of the response signal of the molecular emission of the excitation of sample, to avoid the damage of RF coil 3.It is preferably arranged to, RF transmitting Device 5 is the body coil of MR imaging apparatus 1, and can be worked under operating mode and test pattern, wherein is being tested The signal emitted under mode has the amplitude smaller than the signal emitted in the operational mode.For example, RF transmitter 5 can work Switch between mode and test pattern.It is also contemplated that there is the RF transmitter of the external add-in for generating test signal 20 5, wherein additional RF transmitter is not body coil, and is inserted into hole, to carry out the transmitting of test signal.

RF coil 3 directly detects the test signal 20 of the transmitting of RF transmitter 5.In response to testing signal 20, RF coil 3 is provided Output signal 21.The output signal 21 is preferably the electric signal with certain amplitude and/or regular hour correlation.Pass through 30 output signals 21 are analyzed, can determine Performance figure 11.In other words, in test mode, test RF transmitter 5 emitted Signal 20 is transmitted directly to RF coil 3, without motivating the molecule in MR model or MR sample.As a result, it is possible to advantageous Ground carries out quality analysis QA to magnetic imaging equipment in the case where MR sample/model not being placed in hole 2.Therefore, it checks The process of MR imaging apparatus 1 is simplified.

It is preferred that the amplitude and/or its temporal correlation of detection output signal, and it is carried out with corresponding reference value 22 Compare.Reference value 22 can be the standard value or benchmark of certain coil, or the installation in Medical Resonance imaging device 1 And/or during maintenance, i.e. during its installation, especially with the value of model and/or MR sample measurement.It is preferred that signal-to-noise ratio by The relationship when maximum amplitude and output signal 21 of output signal 21 disappear between the amplitude of output signal 21 determines.Another is closed Key Performance figure can be originated from the temporal correlation of output signal 21.For example, carrying out Fourier transform to output signal 21, provide The specification (specification) of frequency dependence as Performance figure 11, such as specific frequency spectrum, can be used for carrying out quality Analyze QA.

Further, it is contemplated that the temporal correlation of modification test signal 20, to manipulate output signal 20, so as to according to special Surely the form for testing signal 20 extracts the other information about the RF coil 3 tested from corresponding output signal 21.Example Such as, test signal 20 including several different frequencies and/or frequency sweep and/or has rectangular shape or ramp shaped.In particular, In the case where testing signal 20 has several frequencies, the information of the frequency characteristic about RF coil 3 can be extracted.

It is preferred that RF coil receives test signal along with the state of modification Medical Resonance imaging device, advised with identification feature Model.For example, it is contemplated that tuning RF coil 3 and/or detuning, i.e. displacement receives frequency, and it is total to test the frequency of signal to make it Vibration is not resonated.It is preferred that starting detuning/tuning in the received different time about test signal 20.

It is also contemplated that transmitting is sent out by one or several gradient coils 8 during RF coil 3 receives test signal 20 The general signal for the gradient pulse signal 9 penetrated.It is preferable to use the gradient pulse signals 9 of different length and amplitude.As a result, There can be abnormal high amplitude for the gradient pulse signal 9 with specific length or amplitude, registration (register) Output signal 21.Such event may lead to spike in the visualization then to acquired data.

It is also contemplated that the component that test signal 20 corresponds to Medical Resonance imaging device 1 generally draws in the operational mode The noise signal risen.The example of this component can be amplifier 4, such as RF power amplifier 4, in the operational mode immediately Active state is switched to before RF coil 3 receives response signal.The noise that amplifier generally generates is white noise.In view of RF The spectral characteristic of transmitter 5 can extract the spectral characteristic of RF coil 3, which is to indicate the survey of the noise of amplifier 4 The result of trial signal 20.

Further, it is contemplated that detecting test signal 20 by another RF receiver 13 in test mode, wherein this is another A RF receiver provides other output signal 23.It therefore, can be in the retrieval output signal 21 according to test signal 20 When, consider signal to signal fluctuation.Especially it is possible to the test signal for being not suitable for being analyzed be identified, because of these test letters Number with it is standardized test signal difference it is too big.