Abstract: A nuclear magnetic resonance (NMR) spectroscopy or tomography method wherein a sequence of temporally mutually offset radio frequency (RF) pulses is applied onto a spin ensemble like a CPMG multi echo experiment, and wherein the magnetization produced after an initial excitation pulse is transferred to or close to the static pseudo steady state of the initially applied refocussing flip angle &agr;1 is characterized in that magnetization is transferred through gradual change of the refocussing flip angle in subsequent refocussing intervals to or close to the static pseudo steady state of the respectively used refocussing pulse with refocussing flip angle &agr;n such that the echo amplitude of the nth echo generated in this fashion approaches the maximum possible value corresponding to the respective refocussing pulse with refocussing flip angle &agr;n. The RF energy required for excitation of the nuclear spins can thereby be considerably reduced without having to accept signal intensity losses.

Abstract: A method of magnetic resonance (NMR) for spatially resolved measurement of the distribution of NMR signals of metabolites (CSI) with low signal intensity, wherein on a spin ensemble, a sequence of radio frequency (RF) pulses is applied which are mutually offset by a time interval of a repetition time TR and magnetic gradient fields are switched of which at least one causes spatial encoding of the excited spins, is characterized in that the repetition time TR between the exciting RF pulses is selected to be at the most in the magnitude of transverse relaxation time T2 of the spins to be excited, preferably approximately T2/10 and that the magnetic gradient fields are selected such that their action integral is completely balanced over a repetition period of a time period TR such that NMR signal production is carried out according to the principle of steady state free precession (SSFP).

Abstract: A method of MRT according to the principle of signal generation in the driven equilibrium (DE) or also steady state free precession (SFP) wherein a periodic sequence of RF pulses with a flip angle &agr; is applied with a time delay TR wherein the phase of these pulses is alternated in subsequent steps, is characterized in that the periodic sequence of RF pulses is preceded by a sequence of (n+1) pulses for which the following conditions are valid:

Abstract: A method of NMR spectroscopy or tomography, wherein a sequence of temporarily offset radio frequency pulses is applied onto a spin ensemble, is characterized in that after a sequence of pulses with flip angles &agr;1 . . . &agr;n (with &agr;1 . . . &agr;n≧0°) and phases &phgr;1 . . . &phgr;n between which spins are dephased by &phgr;1 . . . &phgr;n, a central refocusing pulse is applied as (n+1)th pulse, followed by a pulse sequence which is mirror-symmetrical to the central refocusing pulse, wherein the flip angles &agr;n+2 . . . &agr;2n+1 and phases &phgr;n+2 . . . &phgr;2n+1 of the pulses have, in comparison with the mirror-symmetrical pulses with &agr;n . . . &agr;1 and &phgr;n . . . &phgr;1, negative sign with respect to amplitude and phase and the dephasings &phgr;n+2 . . . &phgr;2n+1 which are also mirror-symmetrical to the central refocusing pulse in the sequence are equal to the respective mirror-symmetrical dephasings &phgr;n . . .

Abstract: A method of NMR spectroscopy or tomography, wherein a sequence of temporarily offset radio frequency pulses is applied onto a spin ensemble, is characterized in that after a sequence of pulses with flip angles &agr;1 . . . &agr;n (with &agr;1 . . . &agr;n≧0°) and phases &PHgr;1 . . . &PHgr;n between which spins are dephased by &phgr;1 . . . &phgr;n, a central refocusing pulse is applied as (n+1)th pulse, followed by a pulse sequence which is mirror-symmetrical to the central refocusing pulse, wherein the flip angles &agr;n+2 . . . &agr;2n+1 and phases &PHgr;n+2 . . . &PHgr;2n+1 of the pulses have, in comparison with the mirror-symmetrical pulses with &agr;n . . . &agr;1 and &PHgr;n . . . &PHgr;1, negative sign with respect to amplitude and phase and the dephasings &phgr;n+2 . . . &phgr;2n+1 which are also mirror-symmetrical to the central refocusing pulse in the sequence are equal to the respective mirror-symmetrical dephasings &phgr;n . . .

Abstract: A corneal ring for the correction of the refractive power of an eye consists of a part of metal or plastic which is formed into a split ring having at least one turn, or into a ring segment having a diameter or effective diameter matched to the periphery of the cornea of an eye. The ring or ring segment is inserted into a ring channel which is formed with a special instrument in the cornea of the eye and the radius of curvature of the ring or ring segment is subsequently adjusted by a laser beam, or by radiation, or electromagnetic induction, or magnetism to achieve a fine correction of the refractive power of the eye.

Abstract: A method for magnetic resonance imaging (NMR) subjects a sample of magnetic spins, having differing Larmor frequencies and located in an external magnetic field, to a sequence of at least two radio frequency pulse sequences in time separation tm with respect to each other, wherein the difference in Larmor frequencies is due to the type of nuclei, to the inhomogeneities of the magnetic field utilized, or through action of an additional magnetic field gradient and wherein the first radio frequency pulse sequence effects excitation of, relative to the distribution of Larmor frequencies, periodic modulation of the z-magnetization having a modulation separation 2&Dgr;&ohgr; and the second radio frequency pulse sequence transfers this periodic modulating z-magnetization into transverse magnetization leading to signal production.

Abstract: A method for localized NMR spectroscopy having a sequence of radio frequency (RF) pulses for excitation and refocussing of spins in metabolites under investigation in an investigation volume, wherein the excitation is effected through an RF pulse of narrow bandwidth in the presence of a slice selection gradient, as well as, if required, an additional limitation of the investigation volume through utilization of refocussing pulses of narrow bandwidth in the presence of mutually orthogonal slice selection gradients, is characterized in that a read-out time te desired for signal production comprises an n-fold repetition of a partial sequence of RF pulses and, if required, gradient switchings at a time separation tcp2 with respect to each other, wherein a refocussing of the spins is effected within each of these refocussing time intervals using a refocussing pulse.

Abstract: A magnetic resonance imaging method comprises exciting spins in an investigation volume via a radio frequency pulse and the signal produced thereby is subsequently read-out after appropriate spatial encoding following a short echo time te. Repetition of the sequence required for spatial encoding occurs in a time interval tr under appropriate variation of the spatially encoding gradient. The radio frequency pulse utilized for excitation has a short time duration and therefore a large excitation band width so that a projection image through a thick projection slice is produced under application of no slice selection gradient or with only a weak slice selection gradient. The time interval tr is sufficiently minimized that the image recording time required for recording of an image lies in the range of one EKG cycle or below. This process of recording a projection image is continuously repeated and a contrast medium bolus administered during the course of this sequential recording.

Abstract: A corneal ring for the correction of the refractive power of an eye consists or a part of metal or plastic which is formed into a split ring having at least one turn, or into a ring segment having a diameter of effective diameter matched to the periphery of the cornea of an eye. The ring or ring segment is inserted into a ring channel which is formed with a special instrument in the cornea of the eye and the radius or curvature of the ring or ring segment is subsequently adjusted by a laser beam, or by radiation, or electromagnetic induction, or magnetism to achieve a fine correction of the refractive power of the eye.

Abstract: A method of nuclear magnetic resonance (NMR) spectroscopy subjects a sample located in a homogeneous external magnetic field to a sequence of two radio frequency (RF) pulses whose strength and duration are chosen to produce an NMR signal, wherein a time and spatially variable magnetic gradient field GF is applied in a time interval between the first RF impulse exciting the NMR signal and read-out of the signal, and an electric field is applied during the excitation sequence. The magnetic gradient field GF is chosen to cause a velocity-dependent change in the phase and/or amplitude of the signals from spins moved in the direction of the magnetic gradient field GF by the electric field and changes in the signal phase and/or signal amplitude of the NMR signal due to the electric field induced motion of spins in charged, polar, or polarizable molecules along the magnetic gradient field are subsequently observed.

Abstract: A method for the production and recording of nuclear magnetic resonance (NMR) signals in chosen regions of an investigational object with which, in an excitation step, a narrow band radio frequency (RF) pulse is irradiated into the investigational object in a homogeneous static magnetic field in the presence of a slice selection gradient G.sub.S in order to produce an NMR signal in a selected slice of the investigational object, and with which, in a recording step, the produced NMR signal is read-out in the presence of a read gradient G.sub.R which is perpendicular to the slice selection gradient G.sub.S, is characterized in that, in a time interval between the excitation step and the recording step, further RF pulses are each irradiated in the presence of a slice selection gradient G.sub.S whereby, in the time intervals between the irradiation of the RF pulses, further gradient pulses are switched-in in the direction of the read gradient G.sub.

Abstract: In a medical resonance imaging method (NMR-tomography) the following program steps are executed in order to localize the position of a finite number e of discrete individual objects in a selected slice within a measuring object after recording of two slice selective projections in different directions: determining the position of the e individual objects based on the previously carried out recording steps; inquiring whether the localization of the e individual objects is unique; if yes, then ending the program execution; if no, then inquiring whether the number n of non-unique possibilities is smaller than a predetermined threshold value s; if yes, then carrying out a further program step with an encoding parameter which is changed with respect to all previously executed steps in accordance with a fixed predetermined scheme and subsequently returning to the first program step; if no, then calculating an encoding parameter which is suitable for resolving at least the majority of non-unique possibilities for th

Abstract: A method for hydraulic control of a toggle lever press in which the velocity of a driving piston rod is increased at least once in the working region of a press ram. The velocity of the press ram is thus kept relatively constant up to bottom dead center (or upper dead center) of the press ram. A toggle lever press has a control adapted for carrying out this method.

Abstract: An improved rapid acquisition relaxation enhanced (RARE) imaging method for measuring nuclear magnetic resonance in selected regions of a body is disclosed. The improved RARE imaging method includes introducing an evolution phase of time duration t.sub.2 between the excitation pulse and the first refocusing pulse of the multi-echo train. The evolution phase is introduced to influence the magnetization of the observed nuclei in such a fashion that the intensity and/or phase of the subsequent signals are influenced as a function of this evolution phase. This allows the effects of flow, motion, diffusion and local magnetic field inhomogenities to be measured.

Abstract: In the case of a method for the generation of nuclear magnetic resonance (NMR) signals from a measuring volume with test substance which is exposed to a highly homogeneous stationary magnetic field B.sub.0, by irradiation of a sequence of at least two radio frequency (RF)-pulses into the measuring volume, wherein the at least two RF-pulses excite nuclear spins of the test substance within the measuring volume in a resonant manner within a frequency band which is narrow with respect to their frequency, the phases of the at least two RF-pulses are selected in dependence upon their frequency in such a manner that the phases of the NMR signals generated by each individual of the at least two RF-pulses are randomised in such a manner that the vectorial sum over the signal intensities of the individual signals is zero, whereas the combination of the at least two RF-pulses leads to the development of observable coherent magnetization of the test substance.

Abstract: A method for obtaining a time sequence of nuclear magnetic resonance (NMR) tomograms of a certain sectional plane in a measuring volume for observation of variations with time of signal intensities from the sectional plane. The method where k data sets f.sup.'k =f.sub.1.sup.'k . . . f.sub.n.sup.'k are recorded for NMR-tomograms with a low spatial resolution characterized by a parameter n in a time sequence with a waiting time t.sub.w between the acquisition of each data set f.sup.'k. The method where, in terms of time before k data sets f.sup.'k, a data set f=f.sub.1 . . . f.sub.m is recorded for an NMR-tomogram of the same sectional plane with a high spatial resolution characterized by a parameter m (i.e. m>>n). Subsequently, by means of said primarily recorded data set, new data sets f.sup.'k are reconstructed from the successively recorded k data sets f.sup.'k for NMR-tomograms of the sectional plane with a high resolution in space and time.

Abstract: Method of measuring the nuclear magnetic resonance in selected areas of a body in order to present images of body cross-sections according to the slice-selective two dimensional Fourier-transformation. Wherein, the body is in a homogeneous magnetic field, exposed to a selection gradient and excited by a selective RF-pulse. Wherein a time-limited phase encoding gradient is applied, and finally by means of a read gradient at least one nuclear resonance signal is generated by gradient inversion in the form of at least one so-called gradient echo. Wherein, the selection gradient, the phase encoding gradient, as well as, the read gradient are arranged orthogonally with respect to one another. Wherein, RF-pulses have a high frequency excitation profile, of which the base frequencies of the high frequency differ by a value .DELTA.f corresponding to the distance between the centers of adjacent layers or slices.

Abstract: For determining flowing material within a body by NMR tomography, a disk-shaped area in the body is excited, whereafter one applies a flow phase gradient directed in the same sense as the selection gradient (1) and comprising two successive, inversely identical sections (3,4) whose values are varied for the successive excitations. The echo signals obtained, which originate substantially from moving material, are received at a reading gradient directed perpendicularly to the selection gradient. 2DFT reconstruction of a set of spin echo signals furnishes an image which contains the spatial coordinate of the reading gradient in one direction and the flow speed of the material flowing in a direction perpendicular to the excited area in the second direction.

Abstract: A method and drive for generating spin echo signals by a sequence of equidistant rf pulses of different amplitude and small flip angle .alpha., which pulses follow each other in very rapid succession. By proper selection of the amplitude, it is ensured that the sequence of equidistant echo signals so obtained has of an image without numerous gradient switching steps heretofore required.