CN102662151A

CN102662151A - Method for compressing and decoding magnetic resonance imaging pulse sequence information

Info

Publication number: CN102662151A
Application number: CN2012101720320A
Authority: CN
Inventors: 宁瑞鹏; 李鲠颖; 杨光
Original assignee: KALEFU MAGNETIC RESONANCE TECH Co Ltd SHANGHAI; East China Normal University
Current assignee: SHANGHAI KANGDA COLORFUL MEDICAL TECHNOLOGY Co.,Ltd.; East China Normal University
Priority date: 2012-05-30
Filing date: 2012-05-30
Publication date: 2012-09-12
Anticipated expiration: 2032-05-30
Also published as: CN102662151B

Abstract

The invention discloses a method for compressing and decoding magnetic resonance imaging pulse sequence information. The method includes: before scanning is started, segmenting the pulse sequence information by a spectrometer computer according to shared information and non-shared information, performing code indexing for the information in each segment and writing an indexed code sequence and information corresponding to indexed codes into a pulse sequence generator; and after scanning is started, using the pulse sequence generator to search the corresponding information according to the indexed codes and then to output updating. By the aid of the method, pulse sequence information quantity can be effectively compressed, and pressure of the pulse sequence generator on data storage capacity, data transmission speed and the like can be reduced.

Description

A kind of method that magnetic resonance imaging pulse sequence information is compressed and decoded

Technical field

The present invention relates to the mr imaging technique field, be specifically related to a kind of method that magnetic resonance imaging pulse sequence information is compressed and decoded.

Background technology

In magnetic resonance imaging spectrometer, pulse-series generator is one of core component, is used to produce the required pulse train of magnetic resonance imaging, other unit (comprising transmitter, receiver and the gradient waveform generator etc.) collaborative work in the control spectrometer.

Along with the development of mr imaging technique, the pulse train in the practical application becomes increasingly complex.Therefore, in Polaroid overall process, the time sequence information amount that needs pulse-series generator to handle is increasing.Adopt prior art (CN 1361419A; ZL 03150591.0) pulse-series generator of design expands and aspect such as data rate lifting has run into bottleneck at data storage capacity.For a part of formation method, Polaroid overall process can be divided into a plurality of release time of TR, therefore can utilize the stand-by period D among the TR ₀, transmit pulse sequence information required among the next TR to pulse-series generator.Yet, in short TR formation method (for example T1 weighted imaging), because D ₀Very short (even being 0) therefore has little time to transmit pulse sequence information required among the next TR.And in other formation methods, all data acquisitions are accomplished in a TR.When adopting these methods to carry out magnetic resonance imaging, the needed whole pulse sequence information that need before sweep start, will form images writes pulse-series generator.For some complicated formation methods (for example three-dimensional blood vessel imaging), Polaroid required whole pulse sequence quantity of information are very big.If adopt such scheme, the memory capacity of pulse-series generator is difficult to support great deal of information like this.Even memory capacity can support that transferring large number of data also can cause the sweep start variable length delay.In practical applications such as blood vessel imaging, need to use contrast preparation, and the sweep start variable length delay can cause the reinforced effects variation of contrast preparation, influences the contrast of MRI.

Summary of the invention

The objective of the invention is to the deficiency of prior art and provide a kind of magnetic resonance imaging pulse sequence information is compressed the method with decoding.This method is before sweep start; By the spectrometer computing machine pulse sequence information is carried out segmentation according to shared information and non-shared information; Then each segment information is carried out index coding, again indexing coding sequence and the index pairing information of encoding is write pulse-series generator.After sweep start,, upgrade output then by the pulse-series generator information corresponding according to the index coding lookup.

The objective of the invention is to realize like this:

A kind of method that magnetic resonance imaging pulse sequence information is compressed and decoded, this method comprises following concrete steps:

1) on the spectrometer computing machine, Polaroid required whole pulse sequence information to be divided by joint, each joint is for gathering the required pulse sequence information of the K of delegation spatial data.

2) respectively save pulse sequence information, find out and respectively save shared message segment, and these shared message segments are carried out the index coding; Non-shared message segment in each joint pulse sequence information is carried out the index coding.

3), generate indexing coding sequence with the whole pulse sequence information of all index coded representations.

4) before sweep start, indexing coding sequence and each index pairing message segment of encoding is write in the internal memory of pulse-series generator, and with first index coding in the memory pointers indexing coding sequence.

5) pulse-series generator receives after the scan start signal from the spectrometer computing machine, carries out decode procedure by the logic control element in the pulse-series generator.Specifically may further comprise the steps:

A) index that reads the current indication of internal memory pointer is encoded, then execution in step b;

B) the index coding as if the current indication of internal memory pointer is the pulse sequence end mark, then execution in step f; Otherwise execution in step c;

C) index point is pointed to index encode first data of pairing message segment, execution in step d then;

D) if the data of the current indication of index point are the message segment end marks, then with the next index coding of memory pointers, execution in step a then; Otherwise execution in step e;

E) output state of the Data Update pulse-series generator of the current indication of index of reference pointer, and index point pointed to next data, execution in step d then;

F) pulse sequence finishes.

The invention has the beneficial effects as follows: in magnetic resonance imaging, gather the required pulse sequence information of each row K spatial data normally identical or part identical.Adopt the present invention's compression pulse time sequence information amount effectively, alleviate the pressure of pulse-series generator at aspects such as data storage capacity and data rates.

Description of drawings

Fig. 1 is a process flow diagram of the present invention;

Fig. 2 is the process flow diagram of decode procedure according to the invention;

Fig. 3 is the embodiment of the invention 1 synoptic diagram;

Fig. 4 is the embodiment of the invention 2 synoptic diagram.

Embodiment

Below in conjunction with accompanying drawing and embodiment characteristic of the present invention and other correlated characteristic are done further to set forth.

Embodiment 1

Consult Fig. 1 and Fig. 2, " magnetic resonance imaging pulse sequence information is compressed and the method for decoding " of the present invention may further comprise the steps:

1, on the spectrometer computing machine, Polaroid required whole pulse sequence information to be divided by joint, each joint is for gathering the required pulse sequence information of the K of delegation spatial data.

2, respectively save pulse sequence information, find out and respectively save shared message segment, and these shared message segments are carried out the index coding; Non-shared message segment in each joint pulse sequence information is carried out the index coding.

3,, generate indexing coding sequence with the whole pulse sequence information of all index coded representations.

4, before sweep start, indexing coding sequence and each index pairing message segment of encoding is write in the internal memory of pulse-series generator, and with first index coding in the memory pointers indexing coding sequence.

5, pulse-series generator receives after the scan start signal from the spectrometer computing machine, carries out decode procedure by the logic control element in the pulse-series generator.Specifically may further comprise the steps:

A) index that reads the current indication of internal memory pointer is encoded, then execution in step b.

B) the index coding as if the current indication of internal memory pointer is the pulse sequence end mark, then execution in step f; Otherwise execution in step c.

C) index point is pointed to index encode first data of pairing message segment, execution in step d then.

D) if the data of the current indication of index point are the message segment end marks, then with the next index coding of memory pointers, execution in step a then; Otherwise execution in step e.

E) output state of the Data Update pulse-series generator of the current indication of index of reference pointer, and index point pointed to next data, execution in step d then.

F) pulse sequence finishes.

Consulting Fig. 3, is example with the 2D_mSE sequence, and it is identical to gather the required pulse sequence information of each row K spatial data in the scanning process.Therefore; The required whole pulse sequence information that form images can be divided into N joint;

; Wherein SN is the number of plies, and NPE is the phase encoding number.The index of pulse sequence is encoded to { 00000001} among Fig. 3.The required whole pulse sequence information that form images are following:

And indexing coding sequence is

.Before sweep start, the data that write in the internal memory of pulse-series generator are following:

Wherein, { 00000000} is the pulse sequence end mark, and { 0,0} is the message segment end mark.

Embodiment 2

Consulting Fig. 4, is example with the 2D_mFSE sequence, gathers the required pulse sequence message part identical (pulse sequence 00000010 pairing part among Fig. 4) of each row K spatial data in the scanning process.Therefore; The required whole pulse sequence information that form images can be divided into N joint;

; Wherein SN is the number of plies, and NPE is the phase encoding number, and ETL is an echo train legth.The index of pulse sequence is encoded to { 00000001} and { 00000010} among Fig. 4.The required whole pulse sequence information that form images are following:

And indexing coding sequence is following:

Before sweep start, the data that write in the internal memory of pulse-series generator are following:

Claims

One kind to magnetic resonance imaging pulse sequence information compress with the decoding method, it is characterized in that this method comprises following concrete steps:

ⅰ, on the spectrometer computing machine, Polaroid required whole pulse sequence information are divided by joint, each joint is for gathering the required pulse sequence information of the K of delegation spatial data;

ⅱ, respectively save pulse sequence information, find out and respectively save shared message segment, and these shared message segments are carried out the index coding; Non-shared message segment in each joint pulse sequence information is carried out the index coding;

ⅲ, the whole pulse sequence information of all index coded representations of usefulness generate indexing coding sequence;

ⅳ, before sweep start, indexing coding sequence and each index pairing message segment of encoding is write in the internal memory of pulse-series generator, and with first index coding in the memory pointers indexing coding sequence;

ⅴ, pulse-series generator receive after the scan start signal from the spectrometer computing machine, carry out decode procedure by the logic control element in the pulse-series generator; Specifically comprise:

A, read the index coding of the current indication of internal memory pointer, then execution in step b;

B, if the index of the current indication of internal memory pointer coding is the pulse sequence end mark, execution in step f then; Otherwise execution in step c;

C, index point is pointed to index encode first data of pairing message segment, execution in step d then;

D, if the data of the current indication of index point are the message segment end marks, then with the next index coding of memory pointers, execution in step a then; Otherwise execution in step e;

The output state of the Data Update pulse-series generator of e, the current indication of index of reference pointer, and index point pointed to next data, execution in step d then;

F, pulse sequence finish.