Spectrospin Ag

Albert-Ludwigs-Universitat Freiburg

Bruker Medizintechnik Gmbh

Universit&auml;tsklinikum Freiburg

Jurgen Hennig

Marcel Muri

Maxim Zaitsev

Arno Nauerth

Jan-Bernd Hovener

Stephan Berner

Andreas Schmidt

Peter Brunner

In a method (to) in which hyperpolarizable tracer molecules (to) are hydrogenated and then optionally also hyperpolarized for magnetic resonance imaging, it is provided that, in a first method step (), a hydrogen solution () having a saturation factor of at least 50% be prepared and that the hydrogenation reaction (to) not be triggered until a subsequent, second method step (). An apparatus () with which the method of the invention (to) is executable is also provided.

Method and apparatus for hydrogenation and hyperpolarization of tracer molecules for magnetic resonance imaging

Improvements in MR spiral imaging are provided in that spiral segments (to) are reordered, in particular alternately traversed and/or permuted. Moreover, repeatedly approaching the same post-trajectory points () between the acquisitions of the spiral segments (to) is provided, in which the post-trajectory points () are located outside of the center () of k-space (), preferably outside of a region () of the k-space () covered by the spiral segments (to).

Magnetic resonance imaging method

Method for measuring the magnetic resonance (NMR) by driven equilibrium

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. Due to the usage of these so-called 'white' RF-pulses, undesired NMR signals in the case of multi-pulse excitations can be suppressed in a simple manner without application of additional gradients.

Method for the generation of NMR signals with coherent phase profile by

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&gt;&gt;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. For almost simultaneous observation of transient proceedings, the method can be combined with three-dimensional NMR recordings instead of sectional images.

Method for observing time variations of signal intensities of a nuclear

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.

Method for determining moving material in a body

Method for generating a sequence of spin echo signals, the application

In a method for the simultaneous measurement of spin resonance signals, in particular NMR signals, from layers located at different depths in a test volume, simultaneous excitation of the different layers is effected by a multiple-component rf excitation pulse P.sub.n, consisting of n individual components P.sub.m with the frequencies .omega..sub.m, which act selectively on defined layers m of the test volume, in the presence of a layer-selective gradient, the individual components P.sub.m having a phase displacement .phi..sub.m which is varied from one sequence to the next by successive addition of a constant phase increment .DELTA..phi..sub.m modulo 360 fixed individually for each individual component P.sub.m. If phase coding is effected according to the 'Fast Fourier Flow Technique' with the aid of a bipolar gradient pulse, then the flow velocity of a medium moving through the test volume can be measured directly in a multi-dimensional Fourier transformation experiment, simultaneous for several flow cross-sections, in a single recording cycle.

Method for the simultaneous measurement of NMR signals, in particular

Method for encoding n parameters in multi-dimensional Fourier NMR spectroscopy. In NMR tomography, recording a third parameter is rendered possible without any additional input, in addition to the determination of the two-dimensional data required for generating an image, by generating phase-encoded double signals. During Fourier transformation the double signals lead to a striated pattern which is characteristic of the amount of the parameter It is possible in this manner to represent in NMR images in particular the velocity of a flowing material or, for example, variations of the static magnetic field, the susceptibility and the chemical displacement.

Method for encoding and displaying N parameters in multi-dimensional

For recording a nuclear magnetic resonance tomogram according to a Fourier-transform method, a Carr-Purcell-Gill-Meiboom pulse sequence is used for the excitation of a body to produce a sequence of spin-echo signals. A time-limited phase-encoding magnetic gradient field G.sub.X is imposed between each pair of 180.degree. pulses of the sequence. The phase-encoding magnetic gradient field is modified after every 180.degree. pulse so that every spin-echo signal corresponds to a different projection of the body. The magnetic gradient fields used in the recording are regulated in intensity and duration in such a way that a spin-phase condition at each 180.degree. pulse of the pulse sequence remains effectively constant. Thereby, it is possible to construct a complete tomographic recording with a single pulse-sequence excitation, so that the time required for such recordings can be reduced to a fraction of the time needed for recording nuclear-magnetic-resonance tomograms conventionally.

Method for measuring nuclear magnetic resonance

NMR tomography permits identification of flowing matter within a closed body, as there is a reduction in signal intensity as a consequence of a saturation of the magnetization in the area of a slice that has been excited for imaging, while freshly inflowing matter has not experienced this saturation and consequently provides a stronger signal. Special excitation sequences permit either virtually complete saturation of stationary tissue, and thus particularly strong emphasis of flowing matter, or excitation of stationary and flowing matter in different zones and with differing intensities, thereby enabling very precise quantitative and even directional flow measurements to be performed.

Growing community of inventors

Freiburg, Germany

Jurgen Hennig