Control device for a magnetic resonance imaging system, and associated imaging assembly and method

Abstract

A control device (3) for a magnetic resonance imaging system (1) for generating a diffusion image of the body of an animal (6) is proposed.

Description

[0001] DESCRIPTION

[0002] TITLE: Control device for magnetic resonance imaging system, associated imaging assembly and method

[0003] The present invention relates to the field of magnetic resonance imaging (MRI) systems, and more particularly relates to a control device for a magnetic resonance imaging system for generating a diffusion image of an animal's body, a magnetic resonance imaging assembly comprising a magnetic resonance imaging system and such a device, and a magnetic resonance imaging method for generating a diffusion image of an animal's body.

[0004] Generally in human medicine, whole-body MRI imaging is performed to image the human body.

[0005] Whole-body MRI involves acquiring high-resolution images of limited segments of the body, which are then fused to reconstruct the body.

[0006] Whole-body MRI imaging combines anatomical sequences and diffusion-weighted imaging sequences.

[0007] Diffusion imaging sequences allow the detection of lesions, for example metastatic or lymph node lesions, thanks to the high contrast between the lesions and their environment and bring a metabolic dimension to the imaging examination. They evaluate the diffusion properties of water molecules and reflect cellular richness and the integrity of cell membranes over time.

[0008] Anatomical sequences allow lesions to be located and the few false-positive observations of diffusion imaging constructed from diffusion sequences to be recognized.

[0009] In human medicine, commonly used fields of view are between 48 and 50 cm with relatively low spatial resolution.

[0010] The implementation of whole-body MRI imaging in veterinary medicine, for example to reconstruct the body of a dog or cat from the parameters of MRI imaging performed on a human body, has insufficient spatial resolution to represent relevant information, in particular lesions.

[0011] The reduction of fields of view and the increase in spatial resolution when examining the body of an animal lead to an increase in noise and a loss of the signal representative of the diffusion of water molecules in the body of the animal so that the image obtained is of poor quality for making a diagnosis.

[0012] In view of the above, the invention proposes to overcome all or part of the aforementioned drawbacks in order to carry out full-body MRI imaging of an animal which can be used to obtain a relevant representation of the lesions.

[0013] The subject of the invention is a magnetic resonance imaging method for generating a diffusion image of an animal's body comprising:

[0014] - a first level of diffusion sequences in strict transverse acquisition with respiratory compensation of a first field of view, the size of the first field of view extending between 30 and 48 cm so that the body of the animal is entirely included in the first field of view, the first level of diffusion sequences comprising: o a first set of tracking sequences comprising the acquisition of a first group of sections of the animal contained in the first field of view in a transverse direction of the animal, the first group of data sections comprising sections with a thickness of between 2 and 6 mm, o a second set of diffusion sequences in echo planar imaging comprising, for each section of the first set of sections, an emission of a plurality of excitation pulses separated from each other by a first repetition duration greater than 4500 ms and less than 10000 ms,o each first excitation pulse comprising:,

[0015] - the emission of a first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section, - after an echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of a second radio frequency electromagnetic wave to compensate for the phase shift linked to the inhomogeneities in said section and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a first set of gradients comprising the emission of a first gradient in the sagittal plane of the animal, a second gradient in the dorsal plane of the animal, and a third gradient in the transverse plane of the animal, the amplitude of the first, second and third gradients being identical and equal to a first gradient value allowing diffusion of the hydrogen atoms of between 600 s / mm2 and 2000 s / mm2,preferably equal to 800 s / mm2 of the hydrogen atoms included in the first field of view, and,

[0016] - after an echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first resulting signal, the first signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, the echo duration being between 45 ms and 100 ms, o a reconstruction of a first set of three diffusion images for each section of the first set of sections from the first signal resulting from said section, and o a fusion of the diffusion images of the first set of sections to obtain a first diffusion image of the body of the animal.

[0017] The spatial resolution of the animal body diffusion image is improved compared to a known state-of-the-art veterinary MRI imaging in which the fields of view are reduced and the spatial resolution is increased when examining the body of an animal. The diffusion sequence step acquired in strict transverse acquisition makes it possible to reduce eddy currents, reduce Nyquist artifacts and simplify registration.

[0018] Respiratory compensation makes it possible to limit as much as possible the artifacts linked to the animal's breathing movements.

[0019] The emission of a plurality of first excitation pulses having the first gradient value between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 by the emission and reception means makes it possible to increase the signal-to-noise ratio of the first signal resulting from each cut.

[0020] Preferably, the first set of diffusion sequences further comprises detecting an expiratory plateau of the animal to determine the duration of the expiratory plateau and the respiratory rate, the first repetition duration being chosen such that the second set of diffusion sequences is included in the duration of the expiratory plateau.

[0021] Advantageously, the determination of the duration of the expiratory plateau and the respiratory rate comprises: o an identification of the sections of the first set of sections comprising at least partially the liver and the lungs of the animal, and o an observation of the displacement of the liver and the lungs from the identified sections of the first set of sections, the duration of the expiratory plateau and the respiratory rate being determined from the relative displacement of the liver with respect to the lungs.

[0022] Preferably, the second set of broadcast sequences further comprises the emission of a control excitation sequence simultaneously with each emission of a first excitation pulse, each control excitation sequence comprising:

[0023] - simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal, of a second control gradient in the dorsal plane of the animal, and of a third control gradient in the transverse plane of the animal, the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the first field of view, and

[0024] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, the method further comprising: o a reconstruction of a control set of three diffusion control images for each section of the first set of sections from the first control signal resulting from said section, o a fusion of the diffusion control images of the first set of sections to obtain a first diffusion control image of the body of the animal,and o determining a control map from the first diffusion image of the animal's body and the first diffusion control image of the animal's body.,

[0025] Preferably, if the size of the animal is greater than 48cm so that the body of the animal is not entirely included in the first field of view, the method comprises the first level of diffusion sequences and further at least a second level of diffusion sequences in strict transverse acquisition of a second field of view, the size of the second field of view extending between 30 and 48 cm and partially covering the first field of view, the first field of view covering a first area of ​​the animal delimited between the thorax and the abdomen of the animal to cover the pulmonary and abdominal areas of the animal, the second field of view covering a second area of ​​the animal delimited between the head and the shoulders of the animal or between the abdomen and the lower limbs of the animal so that the sum of the size of the fields of view of the levels of diffusion sequence is greater than or equal to the size of the animal,the second level of diffusion sequences comprising: o a third set of tracking sequences comprising the acquisition of a second group of data slices of the animal contained in the field of view of the second level of diffusion sequences in a transverse direction of the animal, the second group of data slices comprising slices of thickness equal to the thickness of the slices of the first group of data slices, o a fourth set of diffusion sequences in echo planar imaging comprising, for each slice of the second set of slices, the emission of a plurality of second excitation pulses separated from each other by a second repetition duration greater than 4500 ms and less than 10000 ms, o each second excitation pulse comprising:,

[0026] - the emission of the first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section of the second set of sections,

[0027] - after the echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of the second radio frequency electromagnetic wave and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of the first set of gradients, and

[0028] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a second resulting signal, the second signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, o a reconstruction of a second set of three diffusion images for each section of the second set of sections from the second signal resulting from said section, and o a fusion of the images of the second set of sections of the second set of sections to obtain a second diffusion image of the body of the animal.

[0029] Advantageously, the fourth set of diffusion sequences further comprises the emission of a control excitation sequence simultaneously with each emission of a second excitation pulse, each control excitation sequence comprising:

[0030] - simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal, of a second control gradient in the dorsal plane of the animal, and of a third control gradient in the transverse plane of the animal, the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the second field of view, and

[0031] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, collecting a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, the method further comprising: o a reconstruction of a control set of three diffusion control images for each section of the second set of sections from the first control signal resulting from said section, and o a fusion of the diffusion control images of the second set of sections to obtain a second diffusion control image of the body of the animal.o determining a control map from the second diffusion image of the animal's body and the second diffusion control image of the animal's body.

[0032] Advantageously, the first animal body diffusion image and the second animal body diffusion image are merged to obtain a reconstructed animal body diffusion image.

[0033] Preferably, the method comprises the same number of anatomical levels as the number of diffusion sequence levels, an anatomical level being carried out simultaneously with each diffusion sequence level to reconstruct an anatomical image of each section of each group of sections, the anatomical images of each section of each group of sections being superimposed with the corresponding diffusion image of the animal's body obtained from the first gradient value.

[0034] The invention further relates to a control device for a magnetic resonance imaging system for generating a diffusion image of an animal's body, in which:

[0035] - the device comprises a plurality of means configured to carry out a first level of diffusion sequences in strict transverse acquisition with respiratory compensation of a first field of view, the size of the first field of view extending between 30 and 48 cm so that the body of the animal is entirely included in the first field of view, the plurality of means comprising: o acquisition means configured to acquire a first group of data slices of the animal contained in the first field of view in a transverse direction of the animal, the first group of data slices comprising slices with a thickness of between 2 and 6 mm, o means for transmitting and receiving diffusion sequences in echo planar imaging configured, for each slice of the first set of slices,emitting a plurality of first excitation pulses separated from each other with a first repetition duration greater than 4500 ms and less than 10000 ms, where each first excitation pulse comprises:,

[0036] - the emission of a first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said cup,

[0037] - after an echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of a second radio frequency electromagnetic wave to compensate for the phase shift linked to the inhomogeneities in said section and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a first set of gradients comprising the emission of a first gradient in the sagittal plane of the animal, of a second gradient in the dorsal plane of the animal, and of a third gradient in the transverse plane of the animal, the amplitude of the first, second and third gradients being identical and equal to a first gradient value allowing a diffusion of between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 of the hydrogen atoms included in the first field of view, and

[0038] - after an echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first resulting signal, the first signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, the echo duration being between 45 ms and 100 ms, o reconstitution means configured to reconstitute a first set of three diffusion images for each section of the first set of sections from the first signal resulting from said section, and o first fusion means configured to merge diffusion images of the first set of sections to obtain a first diffusion image of the body of the animal.

[0039] Preferably, the plurality of means further comprises: o detection means configured to detect an expiratory plateau of the animal to determine the duration of the expiratory plateau and the respiratory rate, and o first determination means to choose the first repetition duration such that the second set of diffusion sequences is included in the duration of the expiratory plateau.

[0040] Advantageously, the detection means are configured to: o identify sections of the first set of sections comprising at least partially the liver and the lungs of the animal, and o observe the displacement of the liver and the lungs from the identified sections of the first set of sections, the duration of the expiratory plateau and the respiratory rate being determined from the relative displacement of the liver with respect to the lungs.

[0041] Preferably, the means for transmitting and receiving broadcast sequences in echo planar imaging are further configured to:

[0042] - simultaneously with the emission of the second radio frequency electromagnetic wave, emitting a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal, a second control gradient in the dorsal plane of the animal, and a third control gradient in the transverse plane of the animal, the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the first field of view, and - after the echo duration starting after the emission of the first radio frequency electromagnetic wave, collecting a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal planes,dorsal and transverse of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, o the reconstitution means being further configured to reconstitute a control set of three diffusion control images for each section of the first set of sections from the first control signal resulting from said section, and o the first fusion means being further configured to merge diffusion control images of the first set of sections to obtain a first diffusion control image of the body of the animal, o the device further comprising second determination means configured to determine a determination of a control mapping from the first diffusion image of the body of the animal and the first diffusion control image of the body of the animal.,

[0043] Preferably, if the size of the animal is greater than 48cm so that the body of the animal is not entirely included in the first field of view, the plurality of means are further configured to carry out a second stage of diffusion sequences in strict transverse acquisition of a second field of view, the size of the second field of view extending between 30 and 48 cm and partially covering the first field of view, the first field of view covering a first area of ​​the animal delimited between the thorax and the abdomen of the animal to cover the pulmonary and abdominal areas of the animal, the second field of view covering a second area of ​​the animal delimited between the head and the shoulders of the animal or between the abdomen and the lower limbs of the animal so that the sum of the size of the fields of view of the diffusion sequence stages is greater than or equal to the size of the animal,o the acquisition means being further configured to acquire a second group of data slices of the animal contained in the field of view of the second level of diffusion sequences in a transverse direction of the animal, the second group of data slices comprising slices of thickness equal to the thickness of the slices of the first group of data slices, o means for transmitting and receiving diffusion sequences in echo planar imaging being further configured, for each slice of the second set of slices, to transmit a plurality of second excitation pulses separated from each other by a second repetition duration greater than 4500 ms and less than 10000 ms, o each second excitation pulse comprising:,

[0044] - the emission of the first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section of the second set of sections,

[0045] - after the echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of the second radio frequency electromagnetic wave and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of the first set of gradients, and

[0046] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a second resulting signal, the second signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal plane, the dorsal plane and the transverse plane of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, o the reconstitution means being further configured to reconstitute a second set of three diffusion images for each section of the second set of sections from the second signal resulting from said section, and o the first fusion means being further configured to merge images of the second set of sections of the second set of sections to obtain a second diffusion image of the body of the animal.

[0047] Advantageously: o the means for transmitting and receiving diffusion sequences in echo planar imaging are further configured to:

[0048] - simultaneously with the emission of the second radio frequency electromagnetic wave, emit a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal, a second control gradient in the dorsal plane of the animal, and a third control gradient in the transverse plane of the animal, the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the second field of view, and

[0049] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, collecting a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, o the reconstitution means being further configured to reconstitute a control set of three diffusion control images for each section of the second set of sections from the first control signal resulting from said section, and o the first fusion means being further configured to merge diffusion control images of the second set of sections to obtain a second diffusion control image of the body of the animal,o the device further comprising second determination means configured to determine a determination of a control mapping from the second diffusion image of the animal's body and the second diffusion control image of the animal's body.,

[0050] Preferably, the device further comprises second fusion means configured to merge the first diffusion image of the animal's body and the second diffusion image of the animal's body to obtain a reconstructed diffusion image of the animal's body.

[0051] Advantageously, the device comprises: o control means configured to produce the same number of anatomical levels as the number of diffusion sequence levels, an anatomical level being produced simultaneously at each diffusion sequence level to reconstruct an anatomical image of each section of each group of sections, and o superposition means configured to superimpose the anatomical images of each section of each group of sections with the corresponding diffusion image of the animal's body obtained from the first gradient value.

[0052] The invention also relates to a magnetic resonance imaging assembly comprising a magnetic resonance imaging system and a control device as defined previously connected to the magnetic resonance imaging system.

[0053] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0054] [Fig 1] schematically illustrates an example of a magnetic resonance imaging assembly according to the invention;

[0055] [Fig 2] schematically illustrates an exemplary embodiment of a control device according to the invention;

[0056] [Fig 3] schematically illustrates a first example of a magnetic resonance imaging method according to the invention; and

[0057] [Fig 4] schematically illustrates a second example of a magnetic resonance imaging method according to the invention.

[0058] Figure 1 schematically illustrates an example of a magnetic resonance imaging assembly 1 comprising a magnetic resonance imaging system 2 and a control device 3 connected to said system 2.

[0059] The magnetic resonance imaging system 1 comprises an examination tunnel 4, a table 5 intended to be inserted into the examination tunnel 4 to carry out a magnetic resonance imaging MRI examination.

[0060] An animal 6 is positioned and held on the table 5 to perform a magnetic resonance imaging (MRI) examination, for example of the spine of a dog.

[0061] Animal 6 can be a dog, a cat or any other animal.

[0062] The animal 6 is for example positioned and held by a holding device 7 on the table 5.

[0063] A permanent static magnetic field is applied in the magnetic resonance imaging system 2, the value of the static magnetic field being for example greater than 0.55 Tesla, preferably equal to 1.5 Tesla, more preferably equal to 3 Tesla.

[0064] Figure 2 schematically illustrates an exemplary embodiment of the control device 3.

[0065] The control device 3 comprises acquisition means 8, means 9 for transmitting and receiving broadcast sequences in echo planar imaging, detection means 10, first determination means 11, second determination means 12, reconstitution means 13, first fusion means 14, second fusion means 15, control means 16, and superposition means 17.

[0066] Figure 3 schematically illustrates a first example of a magnetic resonance imaging method for generating a diffusion image of an animal's body 6.

[0067] The method implements the imaging assembly 1.

[0068] In this example, it is assumed that the size of the animal 6 is such that the body of the animal 6 is entirely included in a first field of view of the magnetic resonance imaging system 2 extending between 30 and 48 cm.

[0069] A first level of diffusion sequences in strict transverse acquisition with respiratory compensation of the first field of view is carried out.

[0070] The first level of diffusion sequences includes a first set of spotting sequences, a second set of diffusion sequences in echo planar imaging (EPI).

[0071] During a step 20 of obtaining the first set of tracking sequences, the acquisition means 8 acquire a first group of data sections of the animal 6 contained in the first field of view in a transverse direction of the animal.

[0072] The first group of data slices includes slices with thickness between 2 and 6 mm.

[0073] During a step 21, the detection means 10 detect an expiratory plateau of the animal 6 to determine the duration of the expiratory plateau and the respiratory rate, and the first determination means 11 choose the first repetition duration so that the second set of diffusion sequences is included in the duration of the expiratory plateau.

[0074] The first repetition duration is greater than 4500 ms and less than 10000 ms.

[0075] To determine the duration of the expiratory plateau and the respiratory rate, the detection means 10 identify sections of the first set of sections comprising at least partially the liver and the lungs of the animal 6.

[0076] The detection means 10 observe the movement of the liver and the lungs from the identified sections of the first set of sections.

[0077] The duration of the expiratory plateau and the respiratory rate are determined from the relative displacement of the liver relative to the lungs.

[0078] Alternatively, the method does not include step 21, the method continuing directly to a step 22 after the execution of step 20.

[0079] During step 22 of obtaining the second set of diffusion sequences in echo planar imaging, the transmission and reception means 9 control the magnetic resonance imaging system 2 so that for each slice of the first set of slices, a plurality of first excitation pulses separated from each other by the first repetition duration, and collect and transmit to the transmission and reception means 9 a first resulting signal.

[0080] If the method does not include step 21, the first repetition duration is greater than 4500 ms and less than 10000 ms, and is determined according to the number of cuts included in the first step.

[0081] The first repetition duration is for example determined by an algorithm known from the state of the art.

[0082] Each first excitation pulse includes:

[0083] - the emission of a first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said cup,

[0084] - after an echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of a second radio frequency electromagnetic wave to compensate for the phase shift linked to the inhomogeneities in said section and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a first set of gradients comprising the emission of a first gradient in the sagittal plane of the animal, of a second gradient in the dorsal plane of the animal, and of a third gradient in the transverse plane of the animal, the amplitude of the first, second and third gradients being identical and equal to a first gradient value allowing a diffusion of between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 of the hydrogen atoms included in the first field of view, and

[0085] - after an echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of the first resulting signal, the first resulting signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, the echo duration being between 45 ms and 100 ms.

[0086] During a step 23, the reconstitution means 13 reconstitute a first set of three diffusion images for each section of the first set of sections from the first signal resulting from said section.

[0087] During a step 24, the first fusion means 14 merge diffusion images of the first set of sections to obtain a first diffusion image of the body of the animal 6.

[0088] Since the trail body of animal 6 is embedded in the first field of view, the first diffusion image of the body of animal 6 is a diffusion image of the whole body of animal 6.

[0089] The spatial resolution of the whole body diffusion image of the animal 6 is improved compared to MRI imaging known from the state of the art during which the fields of view are reduced and the spatial resolution is increased when examining the body of an animal.

[0090] The first level of diffusion sequences acquired in strict transverse acquisition makes it possible to reduce eddy currents, reduce Nyquist artifacts and simplify registration.

[0091] The respiratory compensation makes it possible to limit as much as possible the artifacts linked to the breathing movements of the animal 6. The emission of a plurality of first excitation sequences having the first gradient value between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 by the emission and reception means 9 makes it possible to increase the signal-to-noise ratio of the first signal resulting from each section.

[0092] During step 22 of obtaining the second set of diffusion sequences in echo planar imaging, the transmission and reception means 9 can further control the magnetic resonance imaging system 2 so that it transmits a control excitation sequence simultaneously with each transmission of a first excitation, and collects and transmits to the transmission and reception means 9 a first control signal.

[0093] Each control excitation sequence includes:

[0094] - simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal, of a second control gradient in the dorsal plane of the animal, and of a third control gradient in the transverse plane of the animal, the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the first field of view, and

[0095] - after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of the first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients.

[0096] If step 22 comprises the emission of control excitation sequences, during a step 25, the reconstitution means 13 reconstitute a control set of three diffusion control images for each section of the first set of sections from the first control signal resulting from said section.

[0097] During a step 26 the first fusion means 14 merge diffusion control images of the first set of sections to obtain a first diffusion control image of the body of the animal, and during a step 27, the second determination means 12 determine a first control mapping from the first diffusion image of the body of the animal and the first diffusion control image of the body of the animal.

[0098] The first control map includes diffusion coefficients to filter the first diffusion image of the animal's body to exclude areas similar to "false positive" lesions. The first control map is, for example, an ADC type map "apparent diffusion coefficients" in English.

[0099] The method may comprise a step 28 during which the control means 16 control the magnetic resonance imaging system 2 so that it performs the same number of anatomical steps as the number of diffusion sequence steps.

[0100] An anatomical level as known from the technical state is carried out simultaneously with the first level of diffusion sequences to reconstruct an anatomical image of each section of the first group of sections.

[0101] Anatomical images represent tissues of the animal 6.

[0102] The anatomical images of each section of the first group of sections are superimposed by the superposition means 17 with the corresponding diffusion image of the animal's body obtained from the first gradient value.

[0103] The resulting superimposed image makes it possible to locate a lesion appearing on a diffusion image of the animal's body from the foreground of view in relation to the animal's bone structure 6.

[0104] Figure 4 schematically illustrates a second example of the magnetic resonance imaging method for generating a body diffusion image of an animal 6. In this example, it is assumed that the size of the animal 6 is such that the entire body of the animal 6 protrudes from the first field of view of the magnetic resonance imaging system 2 extending between 30 and 48 cm.

[0105] The size of animal 6 is divided into sections between 30 cm and 48 cm, each section being the subject of a step of diffusion sequences in strict transverse acquisition with or without respiratory compensation so that animal 6 is included in several fields of view.

[0106] It is assumed that the method comprises the first stage of diffusion sequences in strict transverse acquisition with respiratory compensation of the first field of view and a second stage of diffusion sequences in strict transverse acquisition of a second field of view.

[0107] Of course, the method can include more than two stages of diffusion sequences in strict transverse acquisition.

[0108] The first field of view of the first level covers a first area of ​​the animal delimited between the thorax and the abdomen of the animal to cover the pulmonary and abdominal areas of the animal.

[0109] The size of the second field of view of the second broadcast sequence level ranges between 30 and 48 cm and partially overlaps the first field of view.

[0110] The second field of view of the second diffusion sequence level covers a second area of ​​the animal delimited between the head and the shoulders of the animal or between the abdomen and the lower limbs of the animal such that the sum of the size of the fields of view of the diffusion sequence levels is greater than or equal to the size of the animal 6.

[0111] The second level of diffusion sequences includes a third set of spotting sequences, a fourth set of diffusion sequences in echo planar imaging “echo planar imaging EPI”.

[0112] It is assumed that the first step is completed before the second step. Alternatively, the second step is completed before the first step.

[0113] We find steps 20 and 22 to 28 described previously (first level of diffusion sequence), step 21 being optional.

[0114] Then, during a step 29, of obtaining the third set of tracking sequences, the acquisition means 8 acquire a second group of data sections of the animal 6 contained in the second field of view in a transverse direction of the animal.

[0115] The second group of data slices has slices of thickness equal to the thickness of the slices in the first group of data slices.

[0116] During a step 30 of obtaining the fourth set of diffusion sequences in echo planar imaging, the transmission and reception means 9 control the magnetic resonance imaging system 2 so that it transmits for each slice of the second set of slices, a plurality of second excitation pulses separated from each other by a second repetition duration, and collects and transmits to the transmission and reception means 9 the resulting first signal.

[0117] The second repetition duration is greater than 4500 ms and less than 10000 ms.

[0118] The second repeat duration is defined by the number of cuts included in each step.

[0119] The second repetition duration is, for example, determined by an algorithm known from the state of the art.

[0120] Each second excitation pulse includes:

[0121] - the emission of the first radio frequency electromagnetic wave,

[0122] - after the echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of the second radio frequency electromagnetic wave and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of the first set of gradients, and - after the echo duration following the emission of the first radio frequency electromagnetic wave, the collection of a second resulting signal, the second resulting signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients.

[0123] During a step 3 1 , the reconstitution means 13 reconstitute a second set of three diffusion images for each section of the second set of sections from the second signal resulting from said section.

[0124] During a step 32, the first fusion means 14 merge diffusion images of the second set of sections to obtain a second diffusion image of the body of the animal 6.

[0125] During step 30 of obtaining the fourth set of diffusion sequences in echo planar imaging, the transmission and reception means 9 can further control the magnetic resonance imaging system 2 so that it transmits the control excitation sequence simultaneously with each transmission of a second excitation, and collects and transmits to the transmission and reception means 9 the first control signal.

[0126] If step 30 comprises the emission of control excitation sequences, during a step 31, the reconstitution means 13 reconstitute the control set of three diffusion control images for each section of the second set of sections from the first control signal resulting from said section.

[0127] During a step 33, the first merging means 14 merge diffusion control images of the second set of sections to obtain a second diffusion control image of the animal's body, and during a step 34, the second determining means 12 determine a second control map from the second diffusion image of the animal's body and the second diffusion control image of the animal's body. The second control map comprises diffusion coefficients making it possible to filter the second diffusion image of the animal's body to exclude areas similar to "false positive" lesions. The second control map is for example a map of the apparent diffusion coefficients (ADC) type.

[0128] The method may comprise a step 35 during which the control means 16 control the magnetic resonance imaging system 2 so that it performs an anatomical level as known from the prior art simultaneously with the second level of diffusion sequences to reconstruct an anatomical image of each section of the second group of sections.

[0129] Anatomical images represent tissues of the animal 6.

[0130] The anatomical images of each section of the second group of sections are superimposed by the superposition means 17 with the corresponding diffusion image of the animal's body obtained from the first gradient value.

[0131] The superimposed image obtained makes it possible to locate a lesion appearing on a diffusion image of the animal's body from the second plane of view in relation to the bone structure of the animal 6.

[0132] During a step 36, the second merging means 15 merge the first diffusion image of the animal's body and the second diffusion image of the animal's body to obtain a reconstructed diffusion image of the animal's body.

[0133] If the body of animal 6 is contained in the first animal body diffusion image and the second animal body diffusion image, the reconstructed animal body diffusion image is a full body diffusion image of animal 6.

[0134] If more than two levels of diffusion sequences are necessary depending on the size of the animal 6, the second fusion means 15 merge all of the diffusion images of the animal's body obtained to obtain a whole-body diffusion image of the animal 6. The first fusion means 14 and the second fusion means 15 implement known image fusion algorithms.

[0135] The superposition means 17 implement known image superposition algorithms. The frequency of the first and second radiofrequency electromagnetic waves is determined according to the amplitude of the static magnetic field.

[0136] For example, when the amplitude of the static magnetic field is equal to 0.55 Tesla, the frequency of the first and second electromagnetic waves is approximately equal to 23.5 MHz, when the amplitude of the static magnetic field is equal to 1.5 Tesla, the frequency of the first and second electromagnetic waves is approximately equal to 64 MHz, and when the amplitude of the static magnetic field is equal to 3 Tesla, the frequency of the first and second electromagnetic waves is approximately equal to 128 MHz. Each level of diffusion sequences allows the diffusion of water molecules from the body of the animal 6 included in the field of view associated with said level of diffusion sequences.

Claims

CLAIMS 1. A magnetic resonance imaging method for generating a diffusion image of an animal's body (6) comprising: ,a first level of diffusion sequences in strict transverse acquisition with respiratory compensation of a first field of view, the size of the first field of view extending between 30 and 48 cm so that the body of the animal is entirely included in the first field of view, the first level of diffusion sequences comprising: o a first set of tracking sequences comprising the acquisition of a first group of data slices of the animal (6) contained in the first field of view in a transverse direction of the animal (6), the first group of data slices comprising slices with a thickness of between 2 and 6 mm, o a second set of diffusion sequences in echo planar imaging comprising for each slice of the first set of slices, an emission of a plurality of first excitation pulses separated from each other by a first repetition duration greater than 4500 ms and less than 10000 ms,o each first excitation pulse comprising: the emission of a first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section, after an echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of a second radio frequency electromagnetic wave for, compensating for the phase shift linked to the inhomogeneities in said section and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a first set of gradients comprising the emission of a first gradient in the sagittal plane of the animal, a second gradient in the dorsal plane of the animal, and a third gradient in the transverse plane of the animal, the amplitude of the first, second and third gradients being identical and equal to a first gradient value allowing a diffusion of between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 of the hydrogen atoms included in the first field of view, and after an echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first resulting signal, the first signal being representative of the magnetic field generated by each hydrogen atom in said section according to the sagittal planes,dorsal and transverse of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, the echo duration being between 45 ms and 100 ms, a reconstruction of a first set of three diffusion images for each section of the first set of sections from the first signal resulting from said section, and a fusion of the diffusion images of the first set of sections to obtain a first diffusion image of the body of the animal., 2. The method of claim 1, wherein the first set of diffusion sequences further comprises detecting an expiratory plateau of the animal (6) to determine the duration of the expiratory plateau and the respiratory rate, the first repetition duration being chosen such that the second set of diffusion sequences is included in the duration of the expiratory plateau.

3. Method according to claim 2, wherein the determination of the duration of the expiratory plateau and the respiratory rate comprises: o an identification of the sections of the first set of sections comprising at least partially the liver and the lungs of the animal (6), and o an observation of the displacement of the liver and the lungs from the identified sections of the first set of sections, the duration of the expiratory plateau and the respiratory rate being determined from the relative displacement of the liver with respect to the lungs.

4. Method according to one of claims 1 to 3, in which the second set of diffusion sequences further comprises the emission of a control excitation sequence simultaneously with each emission of a first excitation pulse, each control excitation sequence comprising: simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal (6), of a second control gradient in the dorsal plane of the animal (6), and of a third control gradient in the transverse plane of the animal (6), the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal at 50 s / mm2 of the hydrogen atoms included in the first field of view, and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal, said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, the method further comprising: o a reconstruction of a control set of three diffusion control images for each section of the first set of sections from the first control signal resulting from said section, o a fusion of the diffusion control images of the first set of sections to obtain a first diffusion control image of the body of the animal,and o determining a control map from the first diffusion image of the animal's body (6) and the first diffusion control image of the animal's body (6)., 5. Method according to any one of claims 1 to 4, wherein if the size of the animal (6) is greater than 48 cm so that the body of the animal is not entirely included in the first field of view, the method comprises the first level of diffusion sequences and further at least a second level of diffusion sequences in strict transverse acquisition of a second field of view, the size of the second field of view extending between 30 and 48 cm and partially covering the first field of view, the first field of view covering a first area of ​​the animal delimited between the thorax and the abdomen of the animal (6) to cover the pulmonary and abdominal region of the animal (6), the second field of view covering a second area of ​​the animal delimited between the head and the shoulders of the animal (6) or between the abdomen and the lower limbs of the animal so that the sum of the size of the fields of view of the diffusion sequence levels is greater than or equal to the size of the animal (6), the second level of diffusion sequences comprising: o a third set of tracking sequences comprising the acquisition of a second group of data slices of the animal (6) contained in the field of view of the second level of diffusion sequences in a transverse direction of the animal (6), the second group of data slices comprising slices of thickness equal to the thickness of the slices of the first group of data slices, o a fourth set of diffusion sequences in echo planar imaging comprising, for each slice of the second set of slices,the emission of a plurality of second excitation pulses separated from each other by a second repetition duration greater than 4500 ms and less than 10000 ms, where each second excitation pulse comprises: the emission of the first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section of the second set of sections, after the echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of the second radio frequency electromagnetic wave and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of the first set of gradients, and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a second resulting signal, the second signal, being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, o a reconstruction of a second set of three diffusion images for each section of the second set of sections from the second signal resulting from said section, and o a fusion of the images of the second set of sections of the second set of sections to obtain a second diffusion image of the body of the animal (6).

6. The method of claim 5, wherein the fourth set of diffusion sequences further comprises the emission of a control excitation sequence simultaneously with each emission of a second excitation pulse, each control excitation sequence comprising: simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a second set of control gradients comprising the emission of a first control gradient in the sagittal plane of the animal (6), of a second control gradient in the dorsal plane of the animal, and of a third control gradient in the transverse plane of the animal (6), the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the second field of view,and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first control signal, the first signal, control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, the method further comprising: o a reconstruction of a control set of three diffusion control images for each section of the second set of sections from the first control signal resulting from said section, and o a fusion of the diffusion control images of the second set of sections to obtain a second diffusion control image of the body of the animal (6). o the determination of a control map from the second diffusion image of the body of the animal (6) and the second diffusion control image of the body of the animal (6).

7. Method according to claim 5 or 6, wherein the first diffusion image of the body of the animal (6) and the second diffusion image of the body of the animal (6) are merged to obtain a reconstructed diffusion image of the body of the animal (6).

8. Method according to one of claims 1 to 6, comprising the same number of anatomical levels as the number of diffusion sequence levels, an anatomical level being carried out simultaneously with each diffusion sequence level to reconstruct an anatomical image of each section of each group of sections, the anatomical images of each section of each group of sections being superimposed with the corresponding diffusion image of the animal's body obtained from the first gradient value.

9. Control device (3) for magnetic resonance imaging system (1) for generating a diffusion image of the body of an animal (6), in which: the device comprises a plurality of means (8, 9, 12, 13, 14, 15, 16, 17) configured to carry out a first level of diffusion sequences in strict transverse acquisition with respiratory compensation of a first field of view, the size of the first field of view extending between 30 and 48 cm so that the body of the animal is entirely included in the first field of view, the plurality of means comprising: o acquisition means (8) configured to acquire a first group of data slices of the animal (6) contained in the first field of view in a transverse direction of the animal (6), the first group of data slices comprising slices with a thickness of between 2 and 6 mm, o means for transmitting and receiving (9) diffusion sequences in echo planar imaging configured, for each slice of the first set of slices,emitting a plurality of first excitation pulses separated from each other by a first repetition duration greater than 4500 ms and less than 10000 ms, where each first excitation pulse comprises: the emission of a first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said section, after an echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of a second radio frequency electromagnetic wave to compensate for the phase shift linked to the inhomogeneities in said section and simultaneously with the emission of the second radio frequency electromagnetic wave, the emission of a first set of, gradients comprising the emission of a first gradient in the sagittal plane of the animal (6), of a second gradient in the dorsal plane of the animal (6), and of a third gradient in the transverse plane of the animal (6), the amplitude of the first, second and third gradients being identical and equal to a first gradient value allowing a diffusion of between 600 s / mm2 and 2000 s / mm2, preferably equal to 800 s / mm2 of the hydrogen atoms included in the first field of view, and after an echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a first resulting signal, the first signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients,the echo duration being between 45 ms and 100 ms, o reconstruction means (13) configured to reconstruct a first set of three diffusion images for each section of the first set of sections from the first signal resulting from said section, and o first fusion means (14) configured to merge diffusion images of the first set of sections to obtain a first diffusion image of the body of the animal., 10. Device according to claim 9, wherein the plurality of means (8, 9, 12, 13, 14, 15, 16, 17) further comprises: o detection means (10) configured to detect an expiratory plateau of the animal (6) to determine the duration of the expiratory plateau and the respiratory rate, and o first determination means (11) to choose the first repetition duration so that the second set of diffusion sequences is included in the duration of the expiratory plateau. 1 1. Device according to claim 10, wherein the detection means (10) are configured to: o identify sections of the first set of sections comprising at least partially the liver and the lungs of the animal (6), and o observe the displacement of the liver and the lungs from the identified sections of the first set of sections, the duration of the expiratory plateau and the respiratory rate being determined from the relative displacement of the liver with respect to the lungs.

12. Device according to one of claims 9 to 11, in which: o the means for transmitting and receiving (9) diffusion sequences in echo planar imaging are further configured to: simultaneously with the transmission of the second radio frequency electromagnetic wave, transmit a second set of control gradients comprising the transmission of a first control gradient in the sagittal plane of the animal (6), of a second control gradient in the dorsal plane of the animal (6), and of a third control gradient in the transverse plane of the animal (6), the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion of between 0 s / mm2 and 50 s / mm2, preferably equal at 50 s / mm2 of the hydrogen atoms included in the first field of view, and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, collecting a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, o the reconstitution means (13) being further configured to reconstitute a control set of three diffusion control images for each section of the first set of sections from the first control signal resulting from said section,and o the first merging means (14) being further configured to merge diffusion control images of the first set of sections to obtain a first diffusion control image of the body of the animal (6), o the device (3) further comprising second determining means (12) configured to determine a determination of a control mapping from the first diffusion image of the body of the animal (6) and the first diffusion control image of the body of the animal (6)., 13. Device according to any one of claims 9 to 12, wherein if the size of the animal (6) is greater than 48 cm so that the body of the animal is not entirely included in the first field of view, the plurality of means (9, 12, 3, 14, 15, 16, 17) of the plurality of means (9, 12, 3, 14, 15, 16, 17) are further configured to carry out a second stage of diffusion sequences in strict transverse acquisition of a second field of view, the size of the second field of view extending between 30 and 48 cm and partially covering the first field of view, the first field of view covering a first area of ​​the animal (6) delimited between the thorax and the abdomen of the animal (6) to cover the pulmonary and abdominal areas of the animal (6), the second field of view covering a second area of ​​the animal (6) delimited between the head and the shoulders of the animal or between the abdomen and the lower limbs of the animal (6) so that the sum of the size of the fields of view of the diffusion sequence levels is greater than or equal to the size of the animal (6), o the acquisition means (8) being further configured to acquire a second group of data slices of the animal (6) contained in the field of view of the second level of diffusion sequences in a transverse direction of the animal (6),the second group of data slices comprising slices of thickness equal to the thickness of the slices of the first group of data slices, o means for transmitting and receiving (9) diffusion sequences in echo planar imaging being further configured, for each slice of the second set of slices, to transmit a plurality of second excitation pulses separated from each other by a second repetition duration greater than 4500 ms and less than 10000 ms, o each second excitation pulse comprising: the emission of the first radio frequency electromagnetic wave to phase the spins of the hydrogen protons contained in said slice of the second set of slices, after the echo duration divided by two following the emission of the first radio frequency electromagnetic wave, the emission of the second radio frequency electromagnetic wave and simultaneously with the emission of the, second radio frequency electromagnetic wave, the emission of the first set of gradients, and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, the collection of a second resulting signal, the second signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients, o the reconstitution means being further configured to reconstitute a second set of three diffusion images for each section of the second set of sections from the second signal resulting from said section,and o the first fusion means being further configured to fuse images of the second set of sections of the second set of sections to obtain a second diffusion image of the body of the animal (6)., 14. Device according to claim 13, in which: o the means for transmitting and receiving (9) diffusion sequences in echo planar imaging are further configured to: simultaneously with the transmission of the second radio frequency electromagnetic wave, transmit a second set of control gradients comprising the transmission of a first control gradient in the sagittal plane of the animal (6), of a second control gradient in the dorsal plane of the animal (6), and of a third control gradient in the transverse plane of the animal (6), the amplitude of the first, second and third control gradients being identical and equal to a second gradient value allowing diffusion between 0 s / mm2 and 50 s / mm2, preferably equal to 50 s / mm2 of the hydrogen atoms included in the second field of view, and after the echo duration starting following the emission of the first radio frequency electromagnetic wave, collecting a first control signal, the first control signal being representative of the magnetic field generated by each hydrogen atom in said section along the sagittal, dorsal and transverse planes of the animal (6), said hydrogen atom being excited by the radio frequency electromagnetic waves and the first set of gradients and the second set of control gradients, o the reconstitution means (13) being further configured to reconstitute a control set of three diffusion control images for each section of the second set of sections from the first control signal resulting from said section,and o the first merging means (14) being further configured to merge diffusion control images of the second set of sections to obtain a second diffusion control image of the animal's body (6), o the device (3) further comprising second determination means (12) configured to determine a determination of a control mapping from the second diffusion image of the animal's body (6) and the second diffusion control image of the animal's body (6)., 15. Device according to claim 13 or 14, further comprising second fusion means (15) configured to merge the first diffusion image of the body of the animal (6) and the second diffusion image of the body of the animal (6) to obtain a reconstructed diffusion image of the body of the animal (6).

16. Device according to one of claims 9 to 15, comprising: o control means (16) configured to produce the same number of anatomical levels as the number of diffusion sequence levels, an anatomical level being produced simultaneously at each diffusion sequence level to reconstruct an anatomical image of each section of each group of sections, and o superposition means (17) configured to superimpose the anatomical images of each section of each group of sections with the corresponding diffusion image of the animal's body (6) obtained from the first gradient value.

17. Magnetic resonance imaging assembly (1) comprising a magnetic resonance imaging system (2) and a control device (3) according to any one of claims 9 to 16 connected to the magnetic resonance imaging system (2).

Images