JP2005013538A - Magnetic resonance imaging equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide magnetic resonance imaging equipment capable of omitting a sequence data changeover operation by a CPU during a sequence operation of a sequencer and having the sequencer executing the high-speed and complicated sequence. <P>SOLUTION: The CPU 8 sets index data and parameter data in an index table 24 and a parameter table 25 of the sequencer 7. Later on, when the CPU 8 feeds a scan start command to an index parameter controller 26, the controller 26 reads the parameter data according to the index data and outputs them to an output part 27. The controller 26 reads a Next Group among the index data, determines whether or not a scan completion command is instructed in the read Next Group and, if it is instructed, completes the scan. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic resonance imaging apparatus.
[0002]
[Prior art]
The magnetic resonance imaging apparatus includes a static magnetic field generation magnetic circuit, a gradient magnetic field generation system, a transmission system, a reception system, a signal processing system, a sequencer, and a central processing unit (hereinafter abbreviated as CPU). Yes.
[0003]
The CPU controls the sequencer, transmission system, reception system, and signal processing system in accordance with a predetermined program. The sequencer operates in a sequence based on a control command from the CPU, and sends various commands necessary for collecting data of the tomographic image of the subject to the transmission system, gradient magnetic field generation system, and reception system.
[0004]
Here, since the sequencer does not have a function of preparing data for controlling the sequence operation in the sequencer, the sequence cannot be reserved in advance.
[0005]
For this reason, it is necessary to read the same or a plurality of sequence data as many times as necessary, regardless of whether the same sequence is repeated or a plurality of sequences are performed.
[0006]
FIG. 10 is a schematic configuration diagram of the sequencer. In FIG. 10, the sequencer 30 includes a memory (parameter table) 28 for storing sequence data (parameter data) and a controller (parameter controller) 29 for controlling the memory.
[0007]
The parameter table 28 can store only one parameter data. As shown in FIG. 10A, the CPU first writes parameter data to the parameter table 28, and the CPU controls the sequence operation of the sequencer 30, so that the sequencer 30 uses the written parameter data. Execute the sequence.
[0008]
By the way, as shown in FIG. 10B, the CPU completes one sequence operation while controlling the sequence operation in either case of using the same sequence or a plurality of sequences. Each time, necessary parameter data must be written in the parameter table, which makes it difficult to speed up a series of sequence operations. Further, when a complicated sequence operation is requested, it is difficult to execute it.
[0009]
Therefore, Patent Document 1 describes a technique for executing a complex pulse sequence by reducing the time required for rewriting a pulse sequence in a magnetic resonance imaging apparatus.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-277085
[Problems to be solved by the invention]
However, in the technique described in Patent Document 1, in order to switch from a certain pulse sequence to a different pulse sequence during a series of pulse sequence operations, the CPU still has to rewrite data even though the rewrite time has been shortened. In other words, it is difficult to shorten the time further, and it is difficult to increase the processing speed.
[0012]
An object of the present invention is to realize a magnetic resonance imaging apparatus including a sequencer that can omit a sequence data switching operation during a sequence operation of a sequencer by a CPU and that can execute a high-speed and complicated sequence.
[0013]
[Means for Solving the Problems]
In order to achieve such an object, the present invention is configured as follows.
(1) A magnetic field generation system (2, 3) that applies a static magnetic field and a gradient magnetic field to a subject, a transmission system (4) that irradiates a high frequency magnetic field to the subject, and a reception system (5) that detects a nuclear magnetic resonance signal A signal processing system (6) for performing image reconstruction calculation using the nuclear magnetic resonance signal detected by the receiving system, an operation control unit (8) for controlling the operation of the entire apparatus, and an operation control unit. A magnetic resonance imaging apparatus having a sequencer (7) for supplying an operation command signal to the magnetic field generation system, the transmission system, and the reception system according to the command and sequence
The sequencer includes a plurality of sequence storage units (24, 25) for storing a plurality of sequence data (parameter data) supplied from the operation control unit and data (index data) designating the execution order of the plurality of sequence data. And a sequence controller (26) for generating a command signal for executing the sequence data stored in the plurality of sequence storage units according to the stored execution order.
[0014]
Since a plurality of sequence data and the execution order thereof are stored in advance in the plurality of sequence storage units, the sequence controller can continuously execute a plurality of sequences without intervention of an operation control unit (CPU). It becomes possible.
[0015]
(2) Preferably, in the magnetic resonance imaging apparatus, the plurality of sequence storage units includes a sequence data table (25) for storing a plurality of sequence data, and an index for storing a plurality of index data assigned a predetermined number. The table (24) is provided, and one index data stores an address (parameter data address) where sequence data to be executed is stored and an index number (Next group) to be referred to next or an end instruction. The sequence controller starts processing from index data of a predetermined number. Then, when the sequence data stored at the address stored in the index data is executed or when an end instruction is read, the process ends.
[0016]
The order of the sequence to be executed can be changed only by changing the index number to be referred to next in the index data. The parameter data stored in the parameter table can be used effectively, and the data rewriting time by the CPU can be shortened.
[0017]
(3) Preferably, in the magnetic resonance imaging apparatus, during operation of the sequence controller, the operation controller rewrites an index number to be referred to next to the index data, so that the sequence controller Refers to the rewritten index number.
[0018]
In the event of a situation where the sequence of execution of the sequence should be changed during the operation of the sequence controller (for example, when re-imaging is required due to body movement of the subject), the operation control unit By rewriting the index number to be referred to, the sequence execution order can be changed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a magnetic resonance imaging apparatus (MRI apparatus) to which the present invention is applied.
[0020]
In FIG. 1, the MRI apparatus is roughly classified into a static magnetic field generating magnetic circuit 2, a gradient magnetic field generating system 3, a transmitting system 4, a receiving system 5, a signal processing system 6, a sequencer 7, and a central processing unit (CPU). 8 and.
[0021]
The static magnetic field generation magnetic circuit 2 is for generating a uniform static magnetic field in a predetermined direction around the subject 1, and includes a high-frequency coil (irradiation coil) 14 of the transmission system 4 and a gradient magnetic field generation system 3. And a high-frequency coil (reception coil) 15 of the reception system 5.
[0022]
The gradient magnetic field generating system 3 generates a gradient magnetic field around the subject 1 from the gradient magnetic field coil 9 by control by the sequencer 7 and current supply by the gradient magnetic field power supply 10.
[0023]
The transmission system 4 includes a high-frequency oscillator 11, a modulator 12, an amplifier 13, and an irradiation coil 14. A reference high-frequency pulse from the high-frequency oscillator 11 is passed through the modulator 12 and the amplifier 13 in response to a command from the sequencer 7. To the irradiation coil 14 to irradiate the subject 1 with a predetermined pulsed electromagnetic wave.
[0024]
The reception system 5 includes a reception coil 15, an amplifier 16, a quadrature detector 17, and an analog / digital converter (ADC) 18. The reception system 5 collects the nuclear magnetic resonance signal (NMR signal) from the subject 1 by sampling through the reception coil 15, the amplifier 16, the quadrature phase detector 17, and the ADC 18 controlled by the sequencer 7. Data is converted and sent to the CPU 8.
[0025]
The signal processing system 6 includes an external storage device including an optical disk 20 a and a magnetic disk 20 b, a display 21, and a keyboard 22. When data from the receiving system 5 is input to the CPU 8, the CPU 8 executes processing such as signal processing and image reconstruction, displays an image of the tomographic plane of the subject 1 on the display 21, and external memory. Store in device 20.
[0026]
The CPU 8 controls the sequencer 7, the transmission system 4, the reception system 5, and the signal processing system 6 according to a predetermined program. The sequencer 7 operates based on a control command from the CPU 8, and sends various commands necessary for collecting data of a tomographic plane image of the subject 1 to the transmission system 4, the gradient magnetic field generation system 3, and the reception system 5. ing.
[0027]
FIG. 2 is a schematic configuration diagram of the sequencer 7.
In FIG. 2, the sequencer 7 includes an index table 24 that can store a plurality of index data, a parameter table 25 that can store a plurality of parameter data, an index parameter controller 26, and an output unit. 27.
[0028]
The index parameter controller 26 reads the parameter data from the parameter table 25 according to the index data stored in the index table 24, and supplies it as operation control data to the gradient magnetic field generation system 3 or the like via the output unit 27.
[0029]
The index table 24 can store a plurality of index data 1... N by a write command from the CPU 8, and each of the index data 1. The address in the parameter table 25 and the address of the index data storing the address of the parameter data to be executed next are described.
[0030]
The address of the index data in which the address of the parameter data to be executed next is stored as described above, such as NextGroup1 and NextGroup2.
[0031]
Further, parameter data corresponding to each of the index data 1... N is also stored in the parameter table 25 by a write command from the CPU 8.
[0032]
As a result, the CPU 8 can reserve a sequence in advance in the sequencer 7. These can be stored at any time by a write command from the CPU 8.
[0033]
When a scan execution command is received from the CPU 8, the index parameter controller 26 first reads the index data 1 to be used first from the plurality of index data from the index table 24.
[0034]
Since the sequence operation to be performed can be known from the index data 1, the index parameter controller 26 reads the parameter data 1 as many times as necessary at the required time.
[0035]
When one sequence operation is completed, the index parameter controller 26 reads NextGroup 1 indicating the storage destination of the data of the next sequence operation in the index data 1.
[0036]
In accordance with this NextGroup 1, the index parameter controller 26 reads index data in which the next sequence is stored.
[0037]
FIG. 3 is an operation explanatory diagram when only one sequence is executed.
As shown in FIG. 3A, the index table 24 stores index data 1 for performing one sequence operation, and the parameter table 25 stores parameter data 1 used for this sequence. Has been.
[0038]
Further, since the sequence is performed only once in NextGroup 1 of the index data 1, an end command is shown. One sequence is completed by the instruction shown in the index data 1 ((B) of FIG. 3).
[0039]
FIG. 4 is an operation explanatory diagram when a plurality of sequences are continuously executed.
As shown in FIGS. 4A to 4C, the index table 24 stores a plurality of index data 1 to N used for a plurality of sequence operations, and parameter data includes Parameter1, Parameter2,... It is stored in multiple numbers.
[0040]
In addition, NextGroup1 of the index data indicates the address of Indexdata2 for the next sequence operation, and similarly, NextGroup2 indicates the address of Indexdata3.
[0041]
In the plurality of sequence operations, first, the first sequence operation is completed using the parameter data 1 according to the command indicated by the index data 1. Next, since NextGroup 1 indicates the address of the index data 2, the second sequence operation is completed using the parameter data 2 according to the instruction indicated in the index data 2.
[0042]
Similarly, since NextGroup2 indicates the address of Indexdata3, the sequence operation is performed accordingly. By such an operation, as shown in FIG. 4D, sequences 1, 2, 3,... Are continuously executed.
[0043]
FIG. 5 is an operation explanatory diagram when one index data is repeated and one sequence is repeatedly executed.
[0044]
In FIG. 5, the index table 24 stores index data 1 to be used, and the parameter table 25 stores a plurality of parameter data to be used.
[0045]
NextGroup 1 indicates the address of the index data 1 itself for a repetitive sequence operation.
[0046]
Thus, when the first sequence operation is completed, NextGroup1 indicates the address of the index data 1, and therefore the second sequence operation is performed again using the index data 1. After that, the repeated sequence operation is performed in the same manner.
[0047]
As a result, as shown in FIG. 5B, the same sequence 1 is continuously executed. The process end command is written from CPU 8 to NextGroup1. Then, when the written end command is read by the index parameter controller 26, the repetitive sequence operation process is ended.
[0048]
FIG. 6 is an operation flowchart of the sequencer 7 of the processing shown in FIGS.
[0049]
In step 100 of FIG. 6, the CPU 8 sets index data and parameter data in the sequencer 7. Thereafter, when the CPU 8 supplies a scan start command to the index parameter controller 26 at step 101, the index parameter controller 26 reads the parameter data according to the index data at step 102.
[0050]
In step 104, the controller 26 generates a waveform and outputs the waveform to the output unit 27.
[0051]
In step 105, the controller 26 determines whether or not the index data currently used is instructed to read again the parameter data indicated by the index data, and if so, returns to step 103.
[0052]
If it is not instructed to read the parameter data indicated by the index data again in step 105, the process proceeds to step 106, and the controller 26 reads NextGroup in the index data.
[0053]
Next, in step 106, it is determined whether or not a scan end command is instructed to the read NextGroup. If not instructed, the process returns to step 102, and if instructed, the scan is terminated.
[0054]
FIG. 7 is an operation explanatory diagram when a switching command to another sequence is issued from the CPU 8 during the repeated sequence operation.
[0055]
During one sequence repetition operation as shown in FIG. 5, the CPU 8 rewrites the address of the index data 1 written in the NextGroup 1 to the address of the index data 2 ((A) in FIG. 7).
[0056]
Thus, when the currently performed sequence operation is completed, the operation is changed to the operation of the index data 2, and another sequence operation can be performed.
[0057]
FIG. 8 is an operation explanatory diagram when it is necessary to change the order during continuous execution of different sequences.
[0058]
When the index data 1 to 3 are stored in the address of the parameter data as shown in FIG. 4 and when some cause occurs during the operation and the sequence order is changed, as shown in FIG. Index data 1 is rewritten to the address of parameter data 3, index data 2 is rewritten to the address of parameter data 1, and index data 3 is rewritten to the address of parameter data 2.
[0059]
In this way, processing is executed in the order of sequence 3 → sequence 1 → sequence 2 as shown in FIG.
[0060]
FIG. 9 is an operation flowchart in the case of rewriting NextGroup or parameter data during the sequence operation.
[0061]
In the flowchart shown in FIG. 9, steps 101 to 107 are the same as the flowchart shown in FIG.
[0062]
In the flowchart shown in FIG. 9, steps 104A and 104B are inserted between step 104 and step 105.
[0063]
In step 104A, the CPU 8 determines whether it is necessary to rewrite NextGroup or parameter data.
[0064]
For example, when body movement of the subject occurs during tomographic imaging, it is determined whether or not it is necessary to repeat the sequence at that time.
[0065]
If it is not necessary to rewrite, the process proceeds to step 105.
[0066]
On the other hand, if it is necessary to rewrite in step 104A, the CPU 8 rewrites NextGroup or parameter data in step 104B, and proceeds to step 105.
[0067]
As described above, according to an embodiment of the present invention, the CPU stores a plurality of index data and parameter data corresponding thereto in a sequencer at any time other than during the sequence operation. According to this, since the index parameter controller is configured to generate and output sequence data, the sequence data switching operation by the CPU during the sequence operation of the sequencer can be omitted, and a high-speed and complicated sequence can be executed. A magnetic resonance imaging apparatus including a sequencer can be realized.
[0068]
In addition, during the sequence operation, the CPU does not need to rewrite data every time one sequence is completed, and thus can perform other operations. Therefore, the CPU can determine whether or not the same sequence must be re-executed during the sequence due to the body movement of the subject. That is, the MRI apparatus can be further enhanced in functionality.
[0069]
In addition, an index table 24 storing a plurality of index data in which parameter data to be executed is stored, an index number to be referred to next is stored, and a plurality of types of parameter data to be executed are stored. Since the parameter table 25 is provided, the order of the sequence to be executed can be changed only by changing the index number to be referred to next in the index data without changing the parameter data of the parameter table. Can do.
[0070]
This makes it possible to effectively use the parameter data stored in the parameter table and to shorten the data rewriting time by the CPU.
[0071]
In the above-described example, the sequence data storage unit is divided into the index table 24 and the parameter table 25, but the parameter data and the execution order thereof are stored in one table. You can also.
[0072]
【The invention's effect】
According to the present invention, it is possible to realize a magnetic resonance imaging apparatus including a sequencer that can omit a sequence data switching operation during a sequence operation of a sequencer by a CPU and that can execute a high-speed and complicated sequence.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a magnetic resonance imaging apparatus (MRI apparatus) to which the present invention is applied.
FIG. 2 is a schematic internal configuration diagram of a sequencer.
FIG. 3 is an explanatory diagram of a single sequence operation of a sequencer.
FIG. 4 is an explanatory diagram of a multiple sequence operation of the sequencer.
FIG. 5 is an explanatory diagram of a single sequence repetition operation of a sequencer.
FIG. 6 is an example of an operation flowchart of the sequencer.
FIG. 7 is an explanatory diagram of a switching operation from a single sequence repetitive operation to another sequence;
FIG. 8 is an operation explanatory diagram when changing the sequence order;
FIG. 9 is another example of an operation flowchart of the sequencer.
FIG. 10 is a schematic internal configuration diagram of a sequencer in the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Subject 2 Static magnetic field generation circuit 3 Gradient magnetic field generation system 4 Transmission system 5 Reception system 6 Signal processing system 7 Sequencer 8 CPU
DESCRIPTION OF SYMBOLS 9 Gradient magnetic field coil 10 Gradient magnetic field power supply 11 High frequency transmitter 12 Modulator 13, 16 Amplifier 14 Irradiation coil 15 Reception coil 17 Quadrature phase detector 18 Analog / digital converter 19 Bed 20a Optical disk 20b Magnetic disk 21 Display 22 Keyboard 24 Index table 25 Parameter table 26 Index parameter controller 27 Output unit

Claims (3)

A magnetic field generation system that applies a static magnetic field and a gradient magnetic field to a subject, a transmission system that irradiates a high frequency magnetic field to the subject, a reception system that detects a nuclear magnetic resonance signal, and a nuclear magnetic resonance signal detected by the reception system A signal processing system for performing image reconstruction calculation, an operation control unit for controlling the operation of the entire apparatus, and an operation command signal for the magnetic field generation system, the transmission system, and the reception system according to commands and sequences supplied from the operation control unit In a magnetic resonance imaging apparatus having a sequencer for supplying
The above sequencer
A plurality of sequence data supplied from the operation control unit, and a plurality of sequence storage units for storing data specifying the execution order of the plurality of sequence data;
A magnetic resonance imaging apparatus comprising: a sequence controller that generates a command signal to be executed in accordance with an execution order in which the sequence data stored in the plurality of sequence storage units is stored. The magnetic resonance imaging apparatus according to claim 1, wherein the plurality of sequence storage units includes a sequence data table that stores a plurality of sequence data, and an index table that stores a plurality of index data with a predetermined number, One index data stores an address where sequence data to be executed is stored and an index number to be referred to next or an end instruction, and the sequence controller starts processing from index data of a predetermined number. The magnetic resonance imaging apparatus ends processing according to sequence data stored at an address stored in index data or an end instruction. 3. The magnetic resonance imaging apparatus according to claim 2, wherein during operation of the sequence controller, the operation controller rewrites an index number to be referred to next to the index data, so that the sequence controller can rewrite the index number. The magnetic resonance imaging apparatus characterized by the above-mentioned.

Images