Abstract: A method for determining a signature index of an observed tissue comprises the step of providing a generic attenuation model of a motion-probing gradient pulse MRI attenuated signal S(b), and providing a reference model parameter vector (pR(i)) corresponding to a reference state of the tissue. On the basis of the evolution of the determined partial differential sensitivities dSi(b) of the model attenuated signal S(b) to each model parameter p(i) at the neutral state attenuated signal SN(b) versus b values, a discrete and narrow size set of key b is built and a series of MRI images of the observed tissue are acquired by using the key b values. Then, for each voxel a signature index (sADC(V), Sdist(V), SCdist(V), Snl(V), SI(V)) of the voxel V is determined as a scalar function depending on a distance between the voxel signal pattern acquired at the key b values and the signal pattern of the reference state of the tissue at the same key b values. An apparatus is configured for implementing such a method.

Abstract: A method to quantify and map iron deposits in the brain with diffusion-weighted magnetic resonance imaging (MRI) is based on the differential sensitivity of mono-polar (MPG) gradient pulse diffusion sequences and bipolar (BPG) sequences on the local magnetic field gradients induced by iron deposits and their cross-term with the diffusion-encoding gradients.

Abstract: Conventionally, it has been impossible to output an image that allows for an easy and accurate diagnosis as to whether or not a malignant tumor is present and that allows for correctly indicating a part with a high or low grade of malignancy in the tumor.

Abstract: A method for determining a signature index of an observed tissue comprises the step of providing a generic attenuation model of a motion-probing gradient pulse MRI attenuated signal S(b), and providing a reference model parameter vector (pR(i)) corresponding to a reference state of the tissue. On the basis of the evolution of the determined partial differential sensitivities dSi(b) of the model attenuated signal S(b) to each model parameter p(i) at the neutral state attenuated signal SN(b) versus b values, a discrete and narrow size set of key b is built and a series of MRI images of the observed tissue are acquired by using the key b values. Then, for each voxel a signature index (sADC(V), Sdist(V), SCdist(V), Snl(V), SI(V)) of the voxel V is determined as a scalar function depending on a distance between the voxel signal pattern acquired at the key b values and the signal pattern of the reference state of the tissue at the same key b values. An apparatus is configured for implementing such a method.

Abstract: A method to quantify and map iron deposits in the brain with diffusion-weighted magnetic resonance imaging (MRI) is based on the differential sensitivity of mono-polar (MPG) gradient pulse diffusion sequences and bipolar (BPG) sequences on the local magnetic field gradients induced by iron deposits and their cross-term with the diffusion-encoding gradients.

Abstract: Conventionally, it has been impossible to output an image that allows for an easy and accurate diagnosis as to whether or not a malignant tumor is present and that allows for correctly indicating a part with a high or low grade of malignancy in the tumor.

Abstract: The invention relates to a method of water diffusion imaging in magnetic resonance imaging in an area of diagnostic interest, characterized in that it comprises, in combination, the administration of a contrast product capable of generating a signal specifically in its specific location area, said location area being included in said area of interest, the application of a water diffusion imaging sequence to the whole area of interest, and the reading of the images in the area of interest, the specific signal due to the contrast product significantly and specifically modifying the signal in the specific location area relative to the signal of the whole area of interest.

Abstract: A method and system for providing prelocalization of a volume of interest and for rapidly acquiring a data set for generating spectroscopic images. Spatial prelocalization of a volume of interest is achieved by providing a presuppression sequence before a stimulated echo (STE) sequence and a suppression sequence during the mixing time (TM) interval of the STE sequence. The presuppression sequence includes a spatial suppression sequence to selectively saturate slices that intersect the plane selected by the STE sequence in order to define a boundary for the volume of interest, and this spatial suppression sequence is substantially repeated during the TM interval of the STE sequence. Spectroscopic imaging data is acquired by an oversampled echo planar spatial-spectral imaging sequence in which the gradient reversal frequency is a integer factor of n greater than the gradient reversal frequency required to sample the spectral width.

Abstract: A method and system for providing prelocalization of a volume of interest and for rapidly acquiring a data set for generating spectroscopic images. Spatial prelocalization of a volume of interest is achieved by providing a presuppression sequence before a stimulated echo (STE) sequence and a suppression sequence during the mixing time (TM) interval of the STE sequence. The presuppression sequence includes a spatial suppression sequence to selectively saturate slices that intersect the plane selected by the STE sequence in order to define a boundary for the volume of interest, and this spatial suppression sequence is substantially repeated during the TM interval of the STE sequence. Spectroscopic imaging data is acquired by an oversampled echo planar spatial-spectral imaging sequence in which the gradient reversal frequency is a integer factor of n greater than the gradient reversal frequency required to sample the spectral width.

Abstract: A hyperthermia applicator/MRI probe assembly for hyperthermia treatment of a subject. The assembly includes a hyperthermia applicator for heating target regions of a subject and a MRI probe which is utilized to monitor temperatures within the heating region. The hyperthermia applicator and MRI probe are coupled to a control system which receives information from the MRI probe and utilizes the information to control the hyperthermia applicator so as to maintain constant, desired temperatures within the heating region. The hyperthermia applicator/MRI probe assembly of the present invention allows for temperature control within about 0.5.degree. C.

Abstract: A device for regulating the throughput of virtual circuits carried by an asynchronous time-division multiplex transmission channel in which the incoming cells of an input asynchronous time-division multiplex channel (mtr) including a header containing a destination indicator which can be used as a virtual circuit identifier are routed to a cell memory (MT) comprising a . . . , MAn), each cell being stored in the virtual circuit buffer memory associated with the virtual circuit to which the cell belongs, and the outgoing cells of an output asynchronous time-division multiplex channel (mte) are read in the same virtual circuit buffer memories (MA1, MA2, . . . , MAn). Cells to be transmitted on the outgoing link are read from the buffer memories in an order such that the cells from the same virtual circuit buffer memory are spaced on average by at least an interval specifier to that virtual circuit.

Abstract: A memory location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions for measuring the throughput of the virtual circuit and then, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read. A clock signal is adapted to supply a current time associated with this virtual circuit. An indication of the measuring interval start time is written into the context (CT) for a virtual circuit upon arrival of a first cell for this virtual circuit. Upon the arrival of a subsequent cell for this virtual circuit, the context is read and from the current time (hc) the time interval start time is subtracted. The time difference is compared to a specified measurement interval duration and the number of cells already received is incremented.

Abstract: A memory location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions for measuring the throughput of the virtual circuit and then, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read. A clock signal is adapted to supply a current time associated with this virtual circuit, and throughput measurement circuits supply, at the arrival of a cell, a virtual circuit throughput measurement for this virtual circuit.

Abstract: The incoming cells of a input asynchronous time-division multiplex channel (mtr) are counted by a counter (FFB) assigned to each virtual circuit which is incremented on each incoming cell of the virtual circuit and decremented periodically. Clock signals define consecutively numbered cell times (ntc). Queue and chaining table (FAVE, FCVN) define a cell time queue (FAF, FAL, FAV) specific to each of the cell times, a virtual circuit being assignable to a cell time by writing its identifier into the corresponding cell time queue. A controller (MC) uses the content of the cell time queues (FAF, FAL, FAV) and, for each cell time, identifies a virtual circuit to be processed and decrements the counter (FFB) belonging to this virtual circuit. The controller further includes arrangements whereby any virtual circuit whose counter is not idle is assigned to one of the cell times to be decremented by virtue of the arrival of this cell time.

Abstract: A memory (MCT) is used in which a location is assigned to each virtual circuit, this location containing a context (CT) that defines the evaluation conditions of the throughput of the virtual circuit and, upon reception of each cell, providing for the context relating to the virtual circuit to which the cell belongs to be read, for the purpose of evaluating the throughput of the virtual circuit. A clock signal (BC) is used to supply a current time associated with this virtual circuit.

Abstract: Movements within volume elements or voxels of a body are depicted by subjecting this body to sequences of electro-magnetic excitation of the SSFP type during an NMR experiment. It is shown that by performing two series of excitation/reading sequences with different sensitization characteristics, it is possible to obtain images of molecular diffusion and/or perfusions in a far quicker and in a far more differentiated way than with standard types of excitation methods, of the spin-echo type for example.

Abstract: By synchronizing the radio-frequency excitations of a nuclear magnetic resonance experiment with the heart beat of a patient, notable improvement is obtained in the measurement of the molecular diffusion parameters of the tissues studied. In particular, good images of the brain are obtained in this way: the parameter represented is the molecular diffusion constant.

Abstract: The invention proposes an imaging process by nuclear magnetic resonance in which a calculated image is given corresponding to the molecular diffusion value at each point of an investigated medium. The diffusion image is obtained by comparing images relative to same sections of the medium and acquired during two excitation sequences, whereof one is not very sensitive to the diffusion and the other is particularly sensitive thereto. These two images undergo comparison in order to produce a diffusion image.

Abstract: The invention proposes an imaging process by nuclear magnetic resonance in which a calculated image is given corresponding to the molecular diffusion value at each point of an investigated medium. The diffusion image is obtained by comparing images relative to same sections of the medium and acquired during two excitation sequences, whereof one is not very sensitive to the diffusion and the other is particularly sensitive thereto. These two images undergo comparison in order to produce a diffusion image.