Abstract: A magnetic resonance imaging apparatus includes an RF coil system with M RF coils (11–18) for detecting RF signals from a region of interest, M being an integer larger than 2, and N receiver channels (C1–C4) for receiving and processing the detected RF signals, N being an integer larger than 1 and smaller than M. At least two RF coils (12, 16; 14, 18) are combined for reception of RF signals of said RF coils with a single receiver channel. The at least two RF coils are selected so as to provide maximum spatially varying coil sensitivities along the principal axis for coil sensitivity encoding. The proposed MRI apparatus provides an optimal solution enabling it to be used with the SENSE method. The individuality is maximized along the preferred or actual sense reduction direction as is spatial distinctness along the axes of primary clinical interest.

Abstract: The invention relates to a method for magnetic resonance imaging (MRI) of at least a portion of a body placed in a stationary and substantially homogeneous main magnetic field. The method comprises the steps of subjecting the body to a diffusion-weighting sequence (DW1), generating a train of MR echoes (E1, E2, E3, E4, E5) by an imaging sequence (EPI1), and measuring this train of MR echoes. These steps are repeated until a complete imaging data set with a sufficient number of phase-encoding steps is measured. Thereafter, the imaging data set is corrected for macroscopic motions by means of an individual phase-correction of each train of MR echoes. Finally, an image is reconstructed from the imaging data.

Abstract: The invention relates to a method for obtaining MRI images in a vertical main field while using a sub-sampling scheme like SENSE. The invention proposes a number of coil arrangements such that the advantages of SENSE (high speed acquisition) and vertical field (open view for the patient so as to avoid sensations of fear and claustrophobia) are combined. The coil arrangements preferably include butterfly coils and are arranged in such a way that they offer access to the patient and also allow the patient to be moved into and out of the imaging volume without interference by the RF coils.

Abstract: In a magnetic resonance imaging method flow quantities and diffusion quantities are measured in the presence of temporary magnetic gradient fields (gradient pulses). Signal amplitudes of the magnetic resonance signals and/or flow and diffusion quantities calculated from the magnetic resonance signals are corrected for non-linearities in the magnetic gradient fields.

Abstract: The proposed MRI apparatus provides a solution to the problem of a limited number of receiver channels. The main idea is to make use of the imaging parameters when selecting and/or combining the RF signals of at least two RF coils into separate receiver channels. Such an imaging parameter may be, for example, the phase encoding direction.

Abstract: A magnetic resonance imaging system comprises an excitation antennae system (13,16) including several antennae for emitting an RF-excitation field [B1(t)]. An activation control unit (ACU) is coupled to the excitation antennae system to activate the excitation antennae system. Individual antennae are activated to simultaneously emit separate RF-excitation constituents [Bn(t)]. The RF-excitation constituents have different activation distributions over k-space. and the time required for the RF-excitation is short even for complex spatial excitation patterns.

Abstract: The invention relates to an MR coil module for use in an MR imaging system for receiving and/or transmitting RF signals.

Abstract: A magnetic resonance imaging method is provided in which the magnetic resonance signals are acquired by sampling a selected region in the k-space. The selected region in the k-space is chosen in dependence on the object or structure to be imaged. In particular an anisotropic central sector in the k-space is chosen, its axis being dependent on the spatial orientation of the object or structure to be imaged. The magnetic resonance imaging method in accordance with the invention is particularly suitable for imaging arteries separately from veins in magnetic resonance angiography.

Abstract: A magnetic resonance imaging method is proposed wherein the MR signal acquisition is performed by separate scanning of central (40) and peripheral (70) sectors. Central and peripheral sectors are selected in an individual plane in the k-space and optionally an intermediate sector (50) between the peripheral and central sectors is also selected. The center (O) in the k-space in the individual plane at issue is situated within the central sector. The scanning of the k-space commences outside the center of the k-space and before or during increasing contrast. Preferably, the scanning is timed such that the center of the k-space is reached at maximum contrast (MR angiography) or at the value zero of the longitudinal magnetization (MR inversion recovery). The central sector is advantageously scanned in a stochastic order. The peripheral sector may be scanned along a spiral-shaped trajectory, radial trajectories or along high-low ordered lines.

Abstract: A magnetic resonance imaging system comprises an excitation antennae system (13,16) including several antennae for emitting an RF-excitation field [B1(t)]. An activation control unit (ACU) is coupled to the excitation antennae system to activate the excitation antennae system. Individual antennae are activated to simultaneously emit separate RF-excitation constituents [Bn(t)]. The RF-excitation constituents have different activation distributions over k-space. and the time required for the RF-excitation is short even for complex spatial excitation patterns.

Abstract: A magnetic resonance imaging system is provided with a system of emission antennas,: for example, emission coils, for generating RF excitation pulses. The RF excitation pulses generate magnetic resonance signals from an object to be examined. The system of emission antennas has a spatially inhomogeneous emission profile. The inhomogeneous emission profile is used for the partial spatial encoding of the magnetic resonance signals in addition to the encoding on the basis of magnetic gradient fields.

Abstract: The invention relates to an MR coil module for use in an MR imaging system for receiving and/or transmitting RF signals.

Abstract: A magnetic resonance imaging method employs sub-sampled signal acquisition from a number of receiver coils such as surface coils. A full field-of-view magnetic resonance image is reconstructed on the basis of the sensitivity profiles of the receiver coils, for example on the basis of the SENSE technique. The reconstruction is carried out mathematically as an optimization, for example, requiring a minimum noise level in the magnetic resonance image. According to the invention, a priori information is also involved in the reconstruction and the a priori information is taken into account especially as a constraint in optimization.

Abstract: A diagnostic imaging system, notably a magnetic resonance imaging system comprises a receiver antenna for picking-up magnetic resonance signals and an ultrasound probe for receiving ultrasound echoes. A reconstruction unit is arranged to reconstruct a diagnostic image from the magnetic resonance signals and the ultrasound echoes in particular, the magnetic resonance image and ultrasound images are registered in a common reference frame and geometric distortions in the ultrasound image are corrected on the basis of the magnetic resonance image. Different tissues types are distinguished in the magnetic resonance image and corrections are made for differences between ultrasound sound velocities in these tissue types. Further, information contained in the magnetic resonance signals can be displayed in combination in the ultrasound echoes.

Abstract: The invention relates to a method for prescription of scanning parameters determining the orientation and location of tomographic imaging planes. The invention facilitates the process of re-scanning a patient at different times. This is achieved by the computation of the current orientation and location of the patient relative to his or her orientation and location during a previous examination by matching (3) a current reference scan image (1) with the image data of a corresponding previous reference scan (2). The current examination scanning parameters are calculated by adjusting the scanning parameters of the previous examination in accordance with the relative position of the patient during the current examination.

Abstract: A diagnostic imaging system, notably a magnetic resonance imaging system comprises a receiver antenna for picking-up magnetic resonance signals and an ultrasound probe for receiving ultrasound echoes. A reconstruction unit is arranged to reconstruct a diagnostic image from the magnetic resonance signals and the ultrasound echoes.

Abstract: The proposed MRI apparatus provides a solution to the problem of a limited number of receiver channels. The main idea is to make use of the imaging parameters when selecting and/or combining the RF signals of at least two RF coils into separate receiver channels. Such an imaging parameter may be, for example, the phase encoding direction.

Abstract: A magnetic resonance imaging method is provided in which the magnetic resonance signals are acquired by sampling a selected region in the k-space. The selected region in the k-space is chosen in dependence on the object or structure to be imaged. In particular an anisotropic central sector in the k-space is chosen, its axis being dependent on the spatial orientation of the object or structure to be imaged. The magnetic resonance imaging method in accordance with the invention is particularly suitable for imaging arteries separately from veins in magnetic resonance angiography.

Abstract: The invention relates to a method for obtaining MRI images in a vertical main field while using a sub-sampling scheme like SENSE. The invention proposes a number of coil arrangements such that the advantages of SENSE (high speed acquisition) and vertical field (open view for the patient so as to avoid sensations of fear and claustrophobia) are combined. The coil arrangements preferably include butterfly coils and are arranged in such a way that they offer access to the patient and also allow the patient to be moved into and out of the imaging volume without interference by the RF coils.

Abstract: In a magnetic resonance imaging method flow quantities and diffusion quantities are measured in the presence of temporary magnetic gradient fields (gradient pulses). Signal amplitudes of the magnetic resonance signals and/or flow and diffusion quantities calculated from the magnetic resonance signals are corrected for non-linearities in the magnetic gradient fields.