Abstract: A method for magnetic resonance imaging is provided that includes using a magnetic resonance imaging system to excite a field of view (FOV) for a target being imaged, using an excitation plan to limit the excited FOV to a relatively narrow band of magnetization, exciting multiple bands of magnetization simultaneously, applying phase encoding along a shortest FOV dimension, acquiring a signal from said simultaneously excited bands of magnetization, and reconstructing and outputting a target image from the acquired signal.

Abstract: Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

Abstract: A method for extracting information encoded in a result of an NMR measurement, including the following steps: providing a first result of an NMR measurement of a sample; providing a second result of an NMR measurement of a calibration sample; calculating a conversion factor being indicative for a dependency between encoded information on the calibration sample and the concentration of at least one constituent of the calibration sample, applying the conversion factor to information encoded in the first result, calculating a validity value for a subset of the encoded information of the first result, the validity value being representative for a fitness of a first subset of the encoded information to be separated from a second subset of the encoded information, and assigning the validity value to the subset of the encoded information for which it was calculated.

Abstract: In a method and system for shutting down a superconducting magnet of a magnetic resonance apparatus using a monitoring processor and an energy store, the monitoring processor determines stored energy stored in the energy store at a first point-in-time, and determines a ramp energy required for shutting down, and determines a second point-in-time based on the stored energy and the ramp energy. At the second point-in-time, shutting down of the superconducting magnet is begun.

Abstract: In a method and magnetic resonance (MR) scanner for acquiring an MR data set of multiple slices of a volume of interest of an examination object (patient), on receipt of a trigger signal relating to the patient's respiration and indicating the start of an acquisition time window, a fat saturation technique is begun and, in one of a number of acquisition blocks having a number of echo trains each relating to a single slice and a single portion of k-space, wherein all the echo trains of each individual acquisition block relate to different slices, magnetic resonance data for the different slices are acquired. A magnetic resonance image of each slice is determined for that slice by combining magnetic resonance data acquired in different acquisition blocks and relating to a portion of k-space. For at least two of the acquisition blocks, a different sequence of the slices to be acquired by the echo trains is used within the acquisition block.

Abstract: A magnetic resonance imaging apparatus according to an embodiment includes a controller and an image reconstruction unit. The controller executes a pulse sequence having spare time during the time after transient of a gradient magnetic field for dephasing, applied in a readout direction after a radio frequency (RF) pulse for excitation is applied, until the first RF pulse for refocusing is applied in the case where imaging based on a fast spin echo method is performed. The image reconstruction unit reconstructs an image from magnetic resonance data collected by executing the pulse sequence.

Abstract: An arrangement for setting the spatial profile of a magnetic field in a working volume of a main field magnet (2), in particular a superconducting main field magnet, of a magnetic resonance installation. The main field magnet is arranged in a cryostat (1) and the spatial profile is set by a passive shim apparatus (3) with magnetic field forming elements which are arranged within the cryostat during operation and which have cryogenic temperatures. The magnetic resonance installation contains a room temperature tube (4), in which the sample volume is situated during operation. The passive shim apparatus is introduced into or removed from the cold region of the cryostat via a vacuum lock (5), without needing to ventilate the cold region of the cryostat. This provides a relatively simple, cost effective, and time-efficient method to carry out a stable field homogenization using a passive shim apparatus.

Abstract: In one embodiment, an MRI apparatus (20) includes “a temperature measuring unit (70A to 70D) performing temperature measurement of a gradient magnetic field coil unit (26)”, a data storing unit (100), a pulse setting unit (102), and an imaging unit. The data storing unit stores the first and second data indicating a shift of a center frequency of magnetic resonance of hydrogen atoms. The first data corresponds to a case of temperature rise of the gradient magnetic field coil unit, and the second data corresponds to a case of temperature fall of that. The pulse setting unit corrects a center frequency of an RF pulse by calculating an estimated shift of the center frequency based on data corresponding to result of the temperature measurement out of the first and second data. The imaging unit performs magnetic resonance imaging based on the corrected RF pulse.

Abstract: An apparatus, a magnetic resonance imaging system, and a method of use are provided for a reception system for transmitting magnetic resonance signals from local coils to an image processing unit of a magnetic resonance imaging system. The apparatus includes an analog receiver for receiving and processing analog signals from the local coils that is configured to directly sample analog signals having different individual frequency bands and/or frequency band pairs, to distinguish the analog signals and to process them differently. The apparatus also includes an A/D converter for converting the processed analog signals from the local coils into digital signals. The apparatus further includes a digital signal processor for processing the digital signals, wherein the digital signal processor includes a Weaver unit and a downstream decimation filter unit.

Abstract: A cylindrical superconducting magnet system for use in magnetic resonance imaging has axially aligned primary superconducting coils that are situated within an outer vacuum chamber (OVC). A thermal radiation shield surrounds the primary superconducting coils within the OVC. A primary gradient coil assembly is axially aligned with the primary superconducting coils and is situated radially within the primary superconducting coils. The cylindrical superconducting magnetic system also includes a secondary gradient coil assembly, that is radially situated outside of the primary superconducting coils and that is mechanically attached to the primary gradient coil assembly.

Abstract: A shimming method for correcting inhomogeneity of a static magnetic field generated by a magnet of a nuclear magnetic resonance imaging machine includes: measuring the magnetic field at a plurality of points over a reference surface; generating a polynomial that solves Laplace's equation with boundary conditions given on the reference surface, the polynomial representing the magnetic field on the reference surface and having a plurality of harmonic terms, each associated with a coefficient; determining the coefficients from the field sampling values; defining a grid for positioning a plurality of correction elements and relating it to the field structure; and calculating the position and magnitude parameters of the correction elements, such that the correction elements affect the coefficients of the magnetic field to obtain the desired field characteristics, wherein the reference surface is a superquadric surface, such that the magnetic field is corrected in a volume delimited by the superquadric surface.

Abstract: A broadband magnetic resonance (MR) receiver is described herein. The MR receiver can be used to process nuclear magnetic resonance (NMR) signals. The MR receiver includes a transformer that amplifies the MR signals and a preamplifier that receives the MR signals from the transformer. The preamplifier includes a common-drain amplifier stage and a common-source amplifier stage.

Abstract: A birdcage resonator (109) for MR imaging, surrounds an examination volume and includes a plurality of rungs (1-16) arranged in parallel to a longitudinal axis of the examination volume. Each rung (1-16) includes a rung capacitance (Crung). Two end rings are arranged at the opposite ends of the rungs (1-16), each end ring includes a plurality of ring capacitances (Cring). Each ring capacitance (Cring) interconnects a pair of adjacent rungs (1-16). Each pair of adjacent rungs and the interconnecting ring capacitances (Cring) form a mesh of the birdcage resonator. The ring capacitances (Cring) and the rung capacitances (Cring) are proportioned so that: —the birdcage resonator (109) has a plurality of resonant modes that are tuned to the same resonance frequency, and the meshes of the birdcage resonator (109) are electromagnetically coupled. An MR device (101) includes the birdcage resonator.

Abstract: Non-linearities of a gradient amplifier (1) for powering a gradient coil (16) are caused by the finite dead time of the amplifier and/or by a forward voltage drop. The gradient amplifier (1) includes a controllable full bridge (8) and an output filter (9). The full bridge (8) is controlled to provide a desired coil current (ic), including receiving a desired duty cycle (aeff) of the gradient amplifier (1), measuring an input current (ifilt) and an output voltage (ucfilt) of the output filter (9), evaluating an modulator duty cycle (amod), and providing the modulator duty cycle (amod) for controlling the full bridge (8). The gradient amplifier (1) powers a gradient coil (16) including at least two half bridges (10), each having at least two power switches (11) connected in series. An output filter (9) connected to a tapped center points of the half bridges (10) between two the power switches (11).

Abstract: A magnetic resonance control sequence with a pulse arrangement that acts selectively in at least two spatial directions in order to excite a limited rotationally symmetrical excitation profile within an examination subject has an RF excitation pulse formed as a sequence of multiple partial RF pulses, and gradient pulses in the two spatial directions that are coordinated with the partial RF pulses so that the RF energy introduction of different partial RF pulses in transmission k-space occurs on circular k-space transmission trajectories that are concentric to one another. The amplitude of the RF envelope of the partial RF pulses is constant during the duration of a traversal of each circular k-space trajectory. The control sequence can also be used in a calibration of a magnetic resonance system.

Abstract: In a method and a magnetic resonance (MR) system for automated determination of the resonance frequency of a nucleus for magnetic resonance examinations, at least one MR signal is detected, and is Fourier-transformed into a spectrum composed of elements that can be represented as a vector. An analysis of the spectrum is conducted, wherein at least two cross-correlation coefficients of at least one model spectrum are determined by use of the measured spectrum. Prior to the analysis, a spectrum matrix having at least two vectors is determined from the spectrum, with each vector of the spectrum matrix being formed using all or some of the spectrum.

Abstract: A magnetic resonance imaging apparatus of an embodiment has a setting unit configured to set a pulse sequence having a pre-pulse for fat suppression and a pulse train for data acquisition for acquiring echo data for image reconstruction, the pulse sequence being provided with a plurality of dummy pulses between the pre-pulse for fat suppression and the head of the pulse train for data acquisition, a data acquisition unit configured to apply an RF pulse and a gradient magnetic field pulse based on the pulse sequence set by the setting unit to a test object so as to acquire the echo data, and an image generation unit configured to reconstruct an image of the test object from the acquired echo data, wherein an application time during which the plural dummy pulses are applied or flip angles of the plural dummy pulses can be adjusted.

Abstract: A B1 magnetic field may be regulated during a magnetic resonance tomography (MRT) imaging sequence.

Abstract: A method of correcting warping of an acquired image in an MRI system, caused by non-linearities in gradient field profiles of gradient coils is set forth, comprising a) constructing a computer model representing conducting pathways for each gradient coil in said MRI system; b) calculating a predicted magnetic field at each point in space for each said gradient coil in said model; c) measuring actual magnetic field at each point in space for each said gradient coil in said MRI system; d) verifying accuracy of said model by comparing said predicted magnetic field to said actual magnetic field at each said point in space and in the event said model is not accurate then repeating a)-d), and in the event said model is accurate then; constructing a distortion map for mapping coordinates in real space to coordinates in warped space of said acquired image based on deviations of said predicted magnetic field from linearity; and unwarping said warping of the acquired image using said distortion map.

Abstract: Example systems, apparatus, and circuits described herein concern a multi-turn transmit surface coil used in parallel transmission in high field MRI. One example apparatus includes a balun network that produces out-of-phase signals that are amplified to drive current-mode class-D (CMCD) field effect transistors (FETs) that are connected by a coil that includes an LC (inductance-capacitance) leg. The LC leg selectively alters the output analog RF signal and the analog RF signal is used in high field parallel magnetic resonance imaging (MRI) transmission. The multi-turn transmit surface coil produces an improved (e.g., stronger) B1 field without increasing heat dissipation.