JPS63132644A - Control signal generator for mri - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Use The present invention is used in the fields of medical diagnostic imaging and signal waveform generation.

The present invention relates to an MRI control signal generator.

MRl:! :,? :! , NMR (Fuai co-QfU
(Magnetic resonance imaging or its device uses D technology to image the spin density of specific atomic nuclei in living organisms.

More specifically, the present invention relates to a control signal generating device for starting various waveform generation and AD sampling in an MRI (magnetic resonance imaging) apparatus.

(B) Prior Art Conventionally, in MRI apparatuses, counter circuits involved in generating various start signals are driven at the same time as the start of S-preparation, and signals are sequentially generated.

(c) MA while the invention is trying to solve In such conventional examples, it is necessary to assemble the counter circuit in accordance with a predetermined pulse sequence, and if the pulse sequence becomes complicated, assembly becomes difficult.
It also lacks flexibility.

In view of the above-mentioned problems, the present invention provides an MRI control signal generation device that allows easy assembly or modification of sequence examples such as specifying which of various start signal generation circuits to apply and what timing to apply. It is to be.

(d) Means for solving the problem The above-mentioned purpose is to generate a control signal for starting generation of various waveforms such as an optimal gradient magnetic field waveform, an excitation RF variable waveform, etc. generated in an MRI apparatus according to imaging conditions. The control signal generator that starts A/D sampling of collected data is the same as the memory and the signal conversion circuit that reads the signal data from the memory and outputs the start signal to a specific waveform generator. This can be achieved by having a counter that reads the count value from the memory and determines the output timing of the start signal by the signal conversion circuit, and a control circuit for the former three.

(e) Effect 8 The start signal generation circuit is not a counter circuit, but 8
To flexibly deal with complicated sequences by sequentially storing data corresponding to a signal and the time until the next signal generation in a memory, and rewriting the contents at the same time as reading them.

(f) Example A preferred embodiment of the invention will be explained based on the drawings.

For comparison, FIG. 4 suggests a conventional control signal generator, and FIG. 5 is a diagram illustrating the generation timing of the 81 signal.

If you want to generate a signal according to the time chart shown in Figure 5, this can be achieved by connecting each of counters 1 to 3 as shown in Figure 4 and changing the initial values given to the 8 counters. However, when the sequence is changed according to the special mode in MRI, it may not be possible to implement it in this form, and the configuration of the counter itself must be changed, resulting in poor flexibility.

FIG. 1 is a block diagram of essential parts showing one embodiment of the present invention.

The signal data to be sequentially generated in the memory 4 and the time (count value) until the next signal is generated are arranged alternately (an example of this configuration is shown in FIG. 2).

A set of signal data and count value is extracted by the control circuit 5 according to its internal reference clock and stored in the signal conversion circuit 6 and the counter 7, respectively.

The signal conversion circuit 6 converts the signal! ! It is converted into a shape (pulse, level, etc.) depending on the neck and output to an external signal generator (not shown). This signal data may have a one-to-one bit correspondence with an externally applied control signal, or may be encoded.

It is also depicted in the figure, but! It is also possible to apply the liM signal not only to the outside but also to the internal control circuit 5 to induce a special operation.

The counter 7 performs a counting operation according to the reference clock, and when a given count value is reached, an instruction is given to the control circuit 5.

The control circuit 5 reads out the next set of signal data and count value from the memory 4 in accordance with the instructions and supplies them to the signal conversion circuit 6 and the counter circuit 7, respectively.

A sequence is executed by repeating such operations, and complex sequences can be flexibly handled by simply setting or rewriting the signal data and count value in the memory 4.

To end one sequence, a set value indicating how many pairs of signal data and count values must be read out is given to the control circuit 5 in advance (or a set value for one sequence is written in the signal data). This is achieved by including a control code indicating termination.

In any case, when one sequence ends, the control circuit 5 recognizes this and moves to line Φ for starting a new sequence, completing an operation, etc.

The control circuit 5 can make the subsequent sequence operation different from the previous one by changing the contents of the memory 4 while arbitrating with the signal conversion circuit 6 and the timing of the counter reading from the memory 4 as necessary. .

Memory 4 has 1+! , J, but also multiple sequences (blocks 1.2, ... n in Figure 3)
Can store data. The start address is set by the control circuit 5.
It is also possible to sequentially operate different sequences by managing the sequence.

(g) Effects According to the present invention, when the data is used as signal data or count value, it can be used as various start signals and as a timing signal for the amount of start signals, but it is not limited to that, and can be used as a timing signal for the amount of start signals. Can it also be used as a control signal for MRI? ! It is possible to flexibly configure a control system that can handle complex pulse sequences.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts showing one embodiment of the present invention, FIG. 2 is a diagram illustrating a memory configuration according to the present invention, FIG. 3 is a diagram illustrating an actual memory configuration, and FIG. 4 is a schematic diagram of a conventional example. , Figure 5 is 8
1 is a diagram illustrating the timing of generation of one signal. 1 to 3 are counters, 4 is a memory, 5 is a control circuit, 6 is a signal conversion circuit, and 7 is a counter. 4th eye figure 1

Claims (1)

[Claims] A device for generating control signals to start generating various waveforms such as an optimal gradient magnetic field waveform and an excitation RF modulation waveform to be generated according to imaging conditions in an MRI apparatus, or a control signal to start A/D sampling of collected data is a memory. and a signal conversion circuit that reads signal data from the memory and outputs it as a start signal to a specific waveform generator.
a counter that reads the count value from the same memory and determines the output timing of the start signal by the signal conversion circuit;
An MRI control signal generator characterized by comprising a control circuit for the above three.