Background technique
Currently, the image technology that can be used for lower-limb deep veins thrombus (Deep Vein Thrombosis, DVT) inspection is main
There is intravenous angiography (Digital Subtraction Angiography, DSA), ultrasound, CT and magnetic resonance imaging etc. four
Class.These four types of methods respectively have superiority and inferiority, and for example, DSA can be with the presence or absence of accurate judgement thrombus and its distribution, but this method is
Invasive inspection, only uses in interventional procedure;Although ultrasound has non-invasive, inspection is convenient and simple and expense is cheap etc.
Advantage, but the excessive gimmick and experience for relying on doctor, and the technology only can determine that thrombus distribution, not can determine that thrombus bolt
Age;CT is higher to the susceptibility of DVT and specificity, but patient receive x-ray dose of radiation it is big, less facing for DVT
Bed checks.In these four types of methods, magnetic resonance is because of its good soft tissue contrast, multi-parameter scanning, the imaging of the full visual field and nothing
Numerous advantages such as any radiation injury are gradually applied to DVT clinical examination.
The mr imaging technique for being usually used in DVT clinical diagnosis mainly has enhancing magnetic resonance intravenous angiography technology
(Contrast Enhanced Magnetic Resonance Venography, CE-MRV), balance steady state free precession imaging
Technology (balanced Steady-state Free Precession, bSSFP) and based on reversion gtadient echo magnetic resonance it is straight
Connect thrombus imaging technology (Magnetic Resonance Direct Thrombus Imaging, MRDTI) these three, wherein
CE-MRV is usually used in judging thrombus presence or absence and distribution, and can be according to the enhanced performance pair of thrombus and vascular wall
Thrombus bolt age carries out according to a preliminary estimate, but CE-MRV checks the circulation time for needing accurate estimation target target vessel, scan operation
There are certain difficulty, meanwhile, the use of contrast agent not only increases inspection fee, but also cannot be used for serious renal insufficiency and pregnant
Woman patient, and the natural bright blood effect of bSSFP technology makes without using contrast agent, the blood flow in vessel lumen is in height
Signal, thrombus are low signal, and in terms of judging whether blood vessel occludes, effect is similar with CE-MRV, but bSSFP technology is only
It can be used for the rapid screening of DVT, the size of thrombus is shown unintelligible, and thrombus bolt age cannot be judged, be also easy to total by magnetic
Vibrating system main field inhomogeneities influences and generates banding artifact, is a kind of T1 weighted gradient echo as this technology of MRDTI
Sequence, the technology carry out thrombus using the existing distinctive paramagnetic properties of ferrihemoglobin a large amount of in subacute stent thrombosis straight
It is connected into picture, specificity with higher and susceptibility, but MRDTI technology is overly dependent upon ferrihemoglobin content to shorten
In the T1 relaxation time, so that thrombus is in highlighted signal in the picture, therefore it is higher (anxious to be diagnosed to be ferrihemoglobin content
Property → subacute) or subacute stage thrombus, and it is helpless to the lower super acute and chronic thrombus of ferrihemoglobin content.
Recently, a kind of magnetic resonance vascular wall imaging technique is proposed to achieve the clinical examination and diagnosis of DVT, but the technology uses
3-dimensional fast spin echo sequence, it is very limited to the inhibitory effect of blood flow signal, it can not completely inhibit in vein lumen
Blood flow signal, so that imaging results are highly susceptible to the pollution of blood flow signal, it is difficult to carry out vascular wall, blood flow and thrombus quasi-
Really distinguish.
Specific embodiment
In order to which the purpose of the present invention, technical solution and beneficial effect is more clearly understood, below in conjunction with attached drawing and implementation
Example, the present invention will be described in further detail.It should be appreciated that specific embodiment described herein is only used to explain this hair
It is bright, it is not intended to limit the present invention.
The embodiment of the present invention provides a kind of lower-limb deep veins thrombus MR imaging method, which comprises to lower limb
The blood flow signal of Deep venou is inhibited and is retained the vascular wall and embolic signal of the deep veins of lower limb, obtains deep veins of lower limb
Preprocessed signal;It is deep that the lower limb are sampled using variable flip angle spin-echo sequence or quick low-angle gradin-echo
The preprocessed signal of vein;Lower-limb deep veins thrombus nuclear magnetic resonance image is obtained according to the obtained data that sample.The present invention is real
It applies example and corresponding lower-limb deep veins thrombus MR imaging apparatus is also provided.It is described in detail separately below.
Attached drawing 1 is please referred to, is the realization for the lower-limb deep veins thrombus MR imaging method that the embodiment of the present invention one provides
Flow diagram mainly includes the following steps that S101 to step S103:
S101 is inhibited to the blood flow signal of deep veins of lower limb and is retained the vascular wall and thrombus letter of deep veins of lower limb
Number, obtain the preprocessed signal of deep veins of lower limb.
As one embodiment of the invention, the blood flow signal of deep veins of lower limb is inhibited and to retain the lower limb deeply quiet
The vascular wall and embolic signal of arteries and veins may is that through parameter regulation, and the blood flow signal of deep veins of lower limb is inhibited and retained
The vascular wall and embolic signal of the deep veins of lower limb.Black blood priming pulse is specifically used, to its radio-frequency pulse flip angle
The two parameters of the number of degree and radio-frequency pulse are adjusted.Black blood priming pulse is by a series of small flip angle radio-frequency pulse α
With dephasing gradient G staggered, as shown in Fig. 2.The compositing characteristic of black blood priming pulse may make flow organization inner proton fast
Fast dephasing, then dephasing is unobvious for static tissue proton.For the blood flow signal for effectively inhibiting deep veins of lower limb, in the embodiment of the present invention
In, the degree of radio-frequency pulse flip angle can be selected in any number between 8 °~18 °, including endpoint value can be 8 ° or 18 °,
The number of radio-frequency pulse can be selected in any number between 75~200, including endpoint value can be 75 or 200.
S102 samples deep veins of lower limb using variable flip angle spin-echo sequence or quick low-angle gradin-echo
Preprocessed signal.
Variable flip angle spin-echo sequence and quick low-angle gradin-echo are three-dimensional FastMRI sequences
Column, wherein being sampled using variable flip angle spin-echo sequence is in fast spin echo (turbo spin echo, TSE) sequence
On the basis of column, using the flip angle radio-frequency pulse reunion proton phase of variation, so that a pulse period (Repetition
Time, TR) in a plurality of k-space line of acquisition, improve collecting efficiency, and have the advantages that signal-to-noise ratio is high.Variable flip angle spin
The signal of echo sequence is as shown in figure 3, θ in figure1、θ2、θ3Deng as variable flip angle, and the size for damaging gradient can basis
Sweep object difference is accordingly adjusted, and adjustable minimum is zero;When damage gradient is adjusted to zero, which is back
It is grouped into conventional variable flip angle spin-echo sequence;Echo time (Echo Time, TE) and TR are also adjustable imaging
Required weight image is imaged for obtaining in parameter.
Quick low-angle gradin-echo is one kind of gradin-echo, and signal is as shown in Fig. 4.Quick small angle
Flip angle θ in degree gradin-echo is smaller and remains unchanged in different cycles, and is imaged using short TR with quick obtaining
Data, same adjustable TR with TE gain of parameter difference weight image is utilizing in embodiments of the present invention in the sequence
It is the minimum value of adjustable extent using only T1 weighted imaging parameter, that is, TR and TE when this sequence carries out data acquisition.
In summary to the analysis of variable flip angle spin-echo sequence or quick low-angle gradin-echo, in this hair
In bright embodiment, it is deeply quiet that the lower limb are sampled using variable flip angle spin-echo sequence or quick low-angle gradin-echo
The preprocessed signal of arteries and veins, which may is that, uses the variable flip angle spin-echo sequence or quick low-angle gradin-echo,
And by adjusting any one or more parameter in pulse period TR, echo time TE and damage gradient, sampling lower limb are deeply quiet
The preprocessed signal of arteries and veins.The T1 of interested deep veins of lower limb in clinic can be obtained by adjusting pulse period TR and echo time TE
Weighted image and t2 weighted image, wherein t1 weighted image can be not only used for checking deep veins of lower limb with the presence or absence of thrombus and
Its position, can be used for judging thrombus bolt age, and t2 weighted image is then to judging that tissues surrounding vascular has with the presence or absence of oedema
There is good suggesting effect;Adjusting damage gradient can be further improved the effect inhibited when deep veins of lower limb imaging to blood flow signal
Fruit, conducive to the lower-limb deep veins thrombus nuclear magnetic resonance image for obtaining no blood signal contamination.
Since lower limb vein thrombus distribution is wide, vascular wall is thin, need to carry out the big imaging visual field (Field of View, FOV)
Three-dimensional high definition scanning, to check the distribution and range of thrombus comprehensively, therefore, the scanning number of plies is more, and sweep time is longer.For contracting
Short sweep time, in embodiments of the present invention, in addition to using variable flip angle spin-echo sequence or quick low-angle gradient to return
Wave train samples the preprocessed signal of deep veins of lower limb, can be combined with parallel sampling, partial Fourier sampling and sparse sampling
One of or a variety of sampling plans the preprocessed signal of the deep veins of lower limb is sampled, with accelerate data acquisition, make
The single sweep operation time controlled within short period, such as 5 minutes, wherein when parallel sampling, except the phase line of middle section is complete
Sampling is outer, and then uniform intervals acquire the phase line of other parts, when partial Fourier samples, only acquires more than half phase line,
Its phase line does not acquire, and when sparse sampling, in addition to the phase line of middle section is fully sampled, the phase line of other parts is adopted at random
Collection.
S103 obtains lower-limb deep veins thrombus nuclear magnetic resonance image according to the data sampled through step S102.
The technical solution difference with the prior art provided in order to further illustrate the present invention, technical solution of the present invention exist
It is tested on 3T magnetic resonance imaging system, and is compared with CE-MRV.Technical solution of the present invention and CE-MRV are in reality
Imaging parameters used in testing are as shown in table 1 below, and representative imaging results are as shown in Fig. 5.
1 technical solution of the present invention of table and CE-MRV in an experiment used in imaging parameters
Attached drawing 5 is the scanning result of technical solution provided by the invention and existing CE-MRV technology to an example patient DVT,
When not using contrast agent, the imaging results of technical solution provided by the invention are consistent with CE-MRV result, such as arrow in figure
Shown in head.
In addition, being scanned by establishing rat suppository model, and using technical solution provided by the invention, this hair is found
The technical solution of bright offer not only can it is intuitive, clearly illustrate thrombus size and range, as shown in the arrow in attached drawing 6, and
And it can show the relationship between thrombus and vascular wall.By analyzing the signal intensity rate of thrombus and rat muscle, it can be found that
The magnetic resonance signal of different bolt age thrombus shows certain changing rule, shows technical solution provided by the invention to thrombus bolt
The judgement in age has certain suggesting effect.
It was found from the exemplary lower-limb deep veins thrombus MR imaging method of above-mentioned attached drawing 1, on the one hand, due to lower limb depth
The blood flow signal of vein is inhibited and retains the vascular wall and embolic signal of the deep veins of lower limb, therefore, under existing
Limb deep vein thrombosis MR imaging method is compared, and can be accurately distinguished vascular wall, blood flow and thrombus, intuitively be shown
Whether show in blood vessel with the presence of thrombus;On the other hand, since variable flip angle spin-echo sequence or quick low-angle gradient return
Therefore the Parameter adjustable of wave train is sampled using variable flip angle spin-echo sequence or quick low-angle gradin-echo
The preprocessed signal of deep veins of lower limb, so that the lower-limb deep veins thrombus nuclear magnetic resonance image obtained according to this can not only show lower limb
Deep venou whether there is thrombus and its distributing position, and can carry out to thrombus tentatively by stages, to formulate clinic diagnosis scheme
Effective information is provided.
Attached drawing 7 is please referred to, is the structure for the lower-limb deep veins thrombus MR imaging apparatus that the embodiment of the present invention seven provides
Schematic diagram.For ease of description, only parts related to embodiments of the present invention are shown for attached drawing 7.The exemplary lower limb of attached drawing 7 are deeply quiet
Arteries and veins thrombus MR imaging apparatus can be the executing subject of the exemplary lower-limb deep veins thrombus MR imaging method of attached drawing 1.
The exemplary lower-limb deep veins thrombus MR imaging apparatus of attached drawing 7 mainly includes preprocessing module 701, the first sampling module 702
With image-forming module 703, in which:
Preprocessing module 701 is inhibited for the blood flow signal to deep veins of lower limb and retains the deep veins of lower limb
Vascular wall and embolic signal, obtain the preprocessed signal of deep veins of lower limb.
First sampling module 702, for using variable flip angle spin-echo sequence or quick low-angle gtadient echo sequence
The preprocessed signal of column sampling deep veins of lower limb.
Variable flip angle spin-echo sequence and quick low-angle gradin-echo are three-dimensional FastMRI sequences
Column, wherein being sampled using variable flip angle spin-echo sequence is in fast spin echo (turbo spin echo, TSE) sequence
On the basis of column, using the flip angle radio-frequency pulse reunion proton phase of variation, so that a pulse period (Repetition
Time, TR) in a plurality of k-space line of acquisition, improve collecting efficiency, and have the advantages that signal-to-noise ratio is high.Variable flip angle spin
The signal of echo sequence is as shown in figure 3, θ in figure1、θ2、θ3Deng as variable flip angle, and the size for damaging gradient can basis
Sweep object difference is accordingly adjusted, and adjustable minimum is zero;When damage gradient is adjusted to zero, which is back
It is grouped into conventional variable flip angle spin-echo sequence;Echo time (Echo Time, TE) and TR are also adjustable imaging
Required weight image is imaged for obtaining in parameter.Quick low-angle gradin-echo is one kind of gradin-echo, is shown
Meaning is as shown in Fig. 4.Flip angle θ in quick low-angle gradin-echo is smaller and remains unchanged in different cycles, and
Using short TR with quick obtaining imaging data, same adjustable TR with TE gain of parameter difference weight image in the sequence,
In embodiments of the present invention, when carrying out data acquisition using this sequence, being using only T1 weighted imaging parameter, that is, TR and TE can
The minimum value of adjustable range.
Image-forming module 703, the data for being obtained according to the sampling of the first sampling module 702 obtain lower-limb deep veins thrombus magnetic
Resonate image.
It should be noted that in the embodiment of the exemplary lower-limb deep veins thrombus MR imaging apparatus of the figures above 7,
The division of each functional module is merely illustrative of, and can according to need in practical application, for example, corresponding hardware configuration requirement or
The convenient of the realization of person's software considers, and above-mentioned function distribution is completed by different functional modules, i.e., the lower limb are deeply quiet
The internal structure of arteries and veins thrombus MR imaging apparatus is divided into different functional modules, to complete whole described above or portion
Divide function.Moreover, the corresponding functional module in the present embodiment can be by corresponding hardware realization in practical application, it can also
It is completed with executing corresponding software by corresponding hardware, for example, preprocessing module above-mentioned, can be has execution aforementioned under
The blood flow signal of limb Deep venou is inhibited and is retained the vascular wall and embolic signal of the deep veins of lower limb, and it is deeply quiet to obtain lower limb
The hardware of the preprocessed signal of arteries and veins, such as preprocessor are also possible to be able to carry out corresponding computer program to complete aforementioned
The general processor or other hardware devices of function;First sampling module as the aforementioned again can be execution and be turned over using variable
Corner spin-echo sequence or quick low-angle gradin-echo sample the hardware of the preprocessed signal of the deep veins of lower limb,
Such as first sampler, be also possible to be able to carry out corresponding computer program to complete the general processor of aforementioned function or
Other hardware devices (each embodiment that this specification provides can all apply foregoing description principle).
The exemplary preprocessing module 701 of attached drawing 7 may include parameter adjustment unit 801, and the present invention is implemented as shown in Fig. 8
The lower-limb deep veins thrombus MR imaging apparatus that example eight provides.Parameter adjustment unit 801 is used for by parameter regulation, to lower limb
The blood flow signal of Deep venou is inhibited and retains the vascular wall and embolic signal of the deep veins of lower limb.
In the exemplary lower-limb deep veins thrombus MR imaging apparatus of attached drawing 8, adjustable parameter includes radio-frequency pulse
The degree of flip angle and the number of radio-frequency pulse, wherein the degree of radio-frequency pulse flip angle can be any between 8 ° to 18 °
Numerical value also includes endpoint value, i.e. the degree of radio-frequency pulse flip angle can be 8 ° or 18 °, and the number of radio-frequency pulse is 75 to 200
Between any number, also include endpoint value, i.e. the number of radio-frequency pulse can be 75 or 200.
Exemplary first sampling module 702 of attached drawing 7 may include that sequential parameter adjusts unit 901, this hair as shown in Fig. 9
The lower-limb deep veins thrombus MR imaging apparatus that bright embodiment nine provides.Sequential parameter adjusts unit 901 and is used for using variable
Flip angle spin-echo sequence or quick low-angle gradin-echo, and by adjust pulse period TR, echo time TE and
Any one or more parameter in gradient is damaged, the preprocessed signal of deep veins of lower limb is sampled, wherein variable flip angle spin
The related notions such as echo sequence, quick low-angle gradin-echo, pulse period TR, echo time TE and damage gradient can join
The explanation for readding previous embodiment, is not repeated herein.
The lower-limb deep veins thrombus MR imaging apparatus of attached drawing 7 to 9 any example of attached drawing may include the second sampling module
1001, the dress of the lower-limb deep veins thrombus magnetic resonance imaging as shown in the embodiment of the present invention ten to 12 of attached drawing 10-a to attached drawing 10-c
It sets.Second sampling module 1001 is for integrating parallel sampling, partial Fourier sampling and one of sparse sampling or a variety of adopts
Sample prescription case samples the preprocessed signal of deep veins of lower limb.
It should be noted that the contents such as information exchange, implementation procedure between each module/unit of above-mentioned apparatus, due to
Embodiment of the present invention method is based on same design, and bring technical effect is identical as embodiment of the present invention method, particular content
It can be found in the narration in embodiment of the present invention method, details are not described herein again.
Those of ordinary skill in the art will appreciate that all or part of the steps in the various methods of above-described embodiment is can
It is completed with instructing relevant hardware by program, which can be stored in a computer readable storage medium, storage
Medium may include: read-only memory (ROM, Read Only Memory), random access memory (RAM, Random
Access Memory), disk or CD etc..
It is provided for the embodiments of the invention lower-limb deep veins thrombus MR imaging method above and device has carried out in detail
Thin to introduce, used herein a specific example illustrates the principle and implementation of the invention, and above embodiments are said
It is bright to be merely used to help understand method and its core concept of the invention;At the same time, for those skilled in the art, foundation
Thought of the invention, there will be changes in the specific implementation manner and application range, in conclusion the content of the present specification is not
It is interpreted as limitation of the present invention.