Abstract: An NMR probe head for investigating a temperature-sensitive test object in a volume under investigation with at least one RF receiver coil which is cooled to cryogenic temperatures during operation, and is surrounded by a housing, wherein at least one heatable separating wall is provided between the RF receiver coil and the test object, is characterized in that the separating wall is produced from a material having excellent heat conducting properties, wherein the separating wall is coupled in a heat conducting fashion to at least one heating element at a separation from the volume under investigation via at least one contact location. The inventive NMR probe head permits disposition of the RF receiver coil in close proximity to the test object to be measured without inadvertently cooling it.

Abstract: An MRI configuration comprising a magnet system for generating a homogeneous magnetic field, a radio frequency (RF) system (105) for generating/detecting an RF field B1, and a gradient system (106) for temporarily superposing defined gradient fields on a magnetic field B0, and an MRI phantom (104) positioned in the volume under investigation, wherein the MRI phantom (104) comprises a chamber (1) disposed in a housing (2) and filled with a liquid, in which a gas bubble (3) forms, wherein the liquid contains nuclei which have an NMR relaxation time T1, of between 100 ms and 20 s, is characterized in that the chamber (1) of the MRI phantom (104) comprises a main chamber (4) and a partial chamber (5), wherein the main chamber (4) is delimited from the partial chamber (5) such that the gas bubble (3) can completely enter the partial chamber (5) due to its buoyancy by changing the spatial orientation of the MRI phantom (104) in the gravitation field, and remains in the partial chamber (5) in a measurement orientati

Abstract: A method for generating MR (magnetic resonance) images of a moving object with a repeating motion pattern at comparable motion states, wherein for at least one motion state, a set of MR data which is completely encoded for producing an MR image is provided from a plurality of successive individual MR measurements with a shorter time separation than a repetition rate of the motion pattern, and wherein at least one data point from each individual MR measurement is used as an indicator for the comparability of several motion states, is characterized in that at least one contiguous region of successive data points is used as indicator within the individual MR measurement, wherein this contiguous region is identically repeated for all individual MR measurements within the respective MR measuring sequence relative to irradiated RF (radio frequency) pulses and switched gradients.

Abstract: An installation for the investigation of objects by means of magnetic resonance has a magnet system for the production of a homogenous magnetic field in an investigational volume and is characterized in that the magnet system is disposed in a magnet room and the investigational volume, in a first operational mode of the installation, is disposed in a safety room which is decoupled in a gas-tight fashion from the magnet room. The installation in accordance with the invention facilitates the investigation of contaminated objects by means of magnetic resonance, wherein the measurement apparatus is not contaminated and simultaneously allows for simple maintenance of the system external to the safety room as well as a simple positioning of the object under investigation.

Abstract: A low-noise preamplifier with an electronic amplifying element having an input (2) and an output (4), and with a first transformer (6) having a primary winding (5) and a secondary winding (8) is characterized in that the input (2) of the electronic amplifying element is the base of a transistor, the gate (G) of a field effect transistor (FET) or the grid of a vacuum tube, and the output (4) of the electronic amplifying element is the collector, the drain (D) or the anode, the output current (Ip) being passed from the electronic amplifying element through the primary winding (5) of the first transformer (6) to the output (7) of the preamplifier, wherein the secondary winding (8) of the first transformer (6) is connected to the input (2) of the electronic amplifying element. This preamplifier can be operated with extremely low noise and at any input impedance, in particular, at 50 ohms or 75 ohms.

Abstract: The invention concerns an apparatus for generating and/or detecting radio frequency (RF)-B1 fields in an investigational volume (10) of a magnetic resonance (MR) device, wherein the apparatus comprises a tubular surface coil (1; 20; 30; 41–44; 51–54; 61) which is formed from a conducting strip and is capacitively closed at least two neighboring ends, wherein the ratio between length L and width W of the strip is ?30, and wherein the volume under investigation (10) is disposed outside of the space surrounded by the strip, bordering an outer surface (9) of the surface coil (1; 20; 30; 41–44; 51–54; 61) such that the B1 field lines, generated by the surface coil (1; 20; 30; 41–44; 51–54; 61) in the volume under investigation (10) extend substantially parallel to this outer surface (9) thereby producing an NMR transmitting and receiving apparatus with improved properties, in particular, one permitting precise influence of the distribution of the RF-B1 field.

Abstract: An installation for the investigation of objects by means of magnetic resonance has a magnet system for the production of a homogenous magnetic field in an investigational volume and is characterized in that the magnet system is disposed in a magnet room and the investigational volume, in a first operational mode of the installation, is disposed in a safety room which is decoupled in a gas-tight fashion from the magnet room. The installation in accordance with the invention facilitates the investigation of contaminated objects by means of magnetic resonance, wherein the measurement apparatus is not contaminated and simultaneously allows for simple maintenance of the system external to the safety room as well as a simple positioning of the object under investigation.

Abstract: A low-noise preamplifier with an electronic amplifying element having an input (2) and an output (4), and with a first transformer (6) having a primary winding (5) and a secondary winding (8) is characterized in that the input (2) of the electronic amplifying element is the base of a transistor, the gate (G) of a field effect transistor (FET) or the grid of a vacuum tube, and the output (4) of the electronic amplifying element is the collector, the drain (D) or the anode, the output current (Ip) being passed from the electronic amplifying element through the primary winding (5) of the first transformer (6) to the output (7) of the preamplifier, wherein the secondary winding (8) of the first transformer (6) is connected to the input (2) of the electronic amplifying element. This preamplifier can be operated with extremely low noise and at any input impedance, in particular, at 50 ohms or 75 ohms.

Abstract: A method of producing magnetic resonance images wherein a (n+1) dimensional k space is scanned by means of an imaging pulse sequence with at least one RF excitation pulse followed by at least one RF refocusing pulse, wherein an incomplete complex spin echo signal Sx is read and digitized by means of a quadrature detector, in one part of the read-out interval [t0−½ta, t0+½ta] which has a central position about the center (t=t0) of the spin echo signal in the time interval [t0−&egr;; t0+&egr;], with n (n=0,1,2, . . .

Abstract: A method of correcting disturbing influences on MR (=magnetic resonance) signals of a substance disposed in the measuring volume of an MR apparatus excited by one or more RF (=radio frequency) excitation pulses, wherein an RF excitation pulse is irradiated onto the substance and a time-dependent MR signal generated thereby is detected and digitized in a phase-sensitive fashion, wherein a time dependence (1)&Dgr;&phgr;i(ti) of the phase of an MR signal, relative to a predetermined reference phase &phgr;refi(ti) of a reference signal Srefi(ti), is determined and digitized from a time dependence (1) si(ti) of the detected and digitized MR signal and one or more correction or controlled variables are determined therefrom. Nearly all measuring points are used for determination of the magnetic field deviation and thus for control to guarantee considerably improved control accuracy.

Abstract: In a method for producing spatially encoded measuring signals of nuclear magnetic resonance from a measuring object, wherein nuclear spins are excited in the measuring object through irradiation of radio frequency (RF) pulses, encoding in reciprocal spatial space (k space) is generated through application of a phase gradient in n dimensions and a magnetic resonance signal from the measuring object is then recorded, wherein k space is scanned in a desired region between kmin and kmax through corresponding repetition of the excitation, encoding and recording steps with different respective phase gradients, and wherein the individual magnetic resonance signals are each associated with a certain weighting (acquisition filter) which is predetermined by the dependence of a desired spatial response function, the time TR(kn) between the start of the (n−1)th excitation step for scanning the measuring signal which corresponds to the point kn−1 in k space and the start of the nth excitation step for scanning