U.S. Philips Corporation

Schneider (usa) Inc.

Graeme C McKinnon

Peter Bosiger

Peter Boesiger

Stefan Fischer

Roland Proksa

Hartwin Bomsdorf

A medical appliance for use in magnetic resonance imaging procedures. A guidewire for vascular procedures is formed by a coaxial cable acting as antenna in a magnetic resonance imaging system.

Guidewire antenna

A magnetic resonance imaging method and device (1) allow for automatic quantitative motion evaluation of a part of an object (4). The pulse and gradient sequence (tsq1, tsq2), which achieves a high contrast tagging grid, is a stimulated echo based tagging sequence, the tagging section (TAG) being applied before the imaging section (img) or being integrated (G.sub.9, G.sub.10) in the imaging section (img).

Magnetic resonance imaging method and device for monitoring motion of a

A magnetic resonance imaging method and device include a processor and a demodulator including a signal sampling device which provide automatic quantitative motion evaluation of a part of an object. Pulse and gradient sequences (tsq) are applied in pairs with spatially differing tagging patterns, images corresponding to the pairs being subtracted so as to form a tagged image. The motion is monitored by scanning of the tagging pattern in the tagged image which permits improved motion evaluation.

A sequence acts--preferably several times--upon an examination region, which sequence comprises two frequency-selective high-frequency pulses not exciting the water component, between which a 180.degree. high-frequency pulse is present. Such a sequence can be more insensitive to imperfections of the 180.degree. pulse in that the second frequency-selective high-frequency pulse is followed by a further frequency-selective high-frequency pulse not exciting the water component and in that between the second frequency-selective high frequency pulse and the further high-frequency pulse as well as after the further high-frequency pulse a magnetic gradient field is switched on and off in such a manner that the time integrals across this gradient field before and after the further high-frequency pulse are equal to each other.

Nuclear magnetic resonance spectroscopy method

Two-dimensional nuclear magnetic resonance spectroscopy with a frequently repeated sequence comprises four high-frequency pulses and acting together with a homogeneous stationary magnetic field upon an examination area, which sequence contains two 180.degree. pulses, halfway between which a third pulse is located. The pulse of the sequence are preceded by a first pulse, whose distance from the second pulse, which is equal to or larger than the relative distance of the other pulses, is varied during the repetition of the sequence. This method is particularly suitable for in vivo examinations of the human body in that during three of the four pulses magnetic gradient fields are operative, whose gradients extend mutually perpendicular to each other, and before and after the third high-frequency pulse a magnetic gradient field is operative having such a duration and such a gradient that the time integral across this field has the same value before the third pulse as after the third pulse.

Method and arrangement for two-dimensional nuclear magnetic resonance

A plurality of sequences act on an examination zone in the presence of a uniform, steady magnetic field, each of the sequences comprising at least three RF pulses which are preferably formed as 90.degree. pulses, applying between the second and the third RF pulse and after the third RF pulse magnetic gradient fields (G.sub.x) having an amplitude and a duration such that spin resonance signals occurring after the third RF pulse are determined exclusively by double quantum coherence. Thus, spatial and spectral determination of a lactate component is simultaneously possible when it is ensured that at least one magnetic gradient field is applied between or after the three RF pulses and when the time integral over at least one of these gradient fields is varied during repetition of the sequences, the second RF pulse (HF.sub.2) being frequency selective to reduce the lipid component (L.sub.1) near the lactate component (M.sub.1) so that the nuclear magnetization of the component (M.sub.2) coupled to the lactate component (M.sub.1) is excited, but not the nuclear magnetization of the component (L.sub.2) coupled to the lipid component (L.sub.1).

Magnetic resonance spectroscopy method and device for performing the

In localized carbon MR spectroscopy, three slice selective pulses which influence the nuclear magnetization in only one slice are generated before a subsequence which is suitable for polarization transfer.

Carbon MR spectroscopy method and device for performing the method

A magnetic resonance spectroscopy method, and apparatus for performing the method, where a plurality of sequences act on an examination zone in the presence of a uniform, steady magnetic field, each sequence comprising at least three RF pulses, the distance between the first two RF pulses being equal to the reciprocal value of twice the scalar coupling constant J, between and after the pulses there being applied magnetic gradient fields having an amplitude and a duration such that the spin resonance signals occurring after the third RF pulse are determined exclusively by double quantum coherence. In order to suppress the fat component situated in the immediate vicinity of the lactate component of lower Larmor frequency, the lipid component at the area of the lactate component is reduced by making the second and/or the third RF pulse frequency-selective so that it acts as an 90.degree. pulse for the component coupled to the lactate component and as a 0.degree. pulse or 180.degree. pulse for the component coupled to the lipid component.

Magnetic resonance spectroscopy method and apparatus for performing the

An rf generator for magnetic resonance imaging apparatus including a modulator in which a carrier is modulated with an envelope signal, and a transmitter stage which is connected subsequent to the modulator generator in which the implementation of the modulating signal enables the expenditure for the transmitter stage be substantially reduced in that the modulator comprises a first modulator section in which the envelope signal is converted into a series of equally long digital pulses whose density corresponds to the amplitude of the envelope signal, in that k different kinds of pulses are provided, in that during each pulse of a given kind the carrier is always switched on with a given phase position which deviates from the phase positions of the carrier which are associated with the pulses of the other kinds by 360.degree./k or an integer multiple thereof, and in that the resultant pulse-wise switched, preferably square-wave carrier acts as a switching signal for the transmitter stage.

RF generator for magnetic resonance imaging apparatus

In the presence of a stationary homogeneous magnetic field a number of generated pulse sequences act on an object examination region, of which sequence each sequence comprises three 180.degree. high-frequency pulses following one another at the same temporal interval, which are preceded by at least one high-frequency pulse which produces a transverse magnetization. An apparatus for carrying out the method includes providing an echo time independent of the J-coupling of the object. The first and third of the three 180.degree. high-frequency pulses and the preceding high-frequency pulse are generated as slice-selective pulses, which excite three slices, the second 180.degree. high-frequency pulse is a frequency-selective pulse which is so shaped that it excites only one of two mutually coupled components of the object, and the nuclear resonance signal produced from the sectional area of the three slices is then processed in order to determine its spectrum.

Method for localized nuclear resonance spectroscopy and apparatus for

MR spectroscopy method and apparatus in which an examination zone is exposed, preferably repeatedly, to a sequence which comprises a first binomial 90.degree. RF pulse, a 180.degree. RF pulse and a second binomial 90.degree. RF pulse which sequence enables separate demonstration of the presence of either lactic acid or lipids in the presence of water. The periods in time between the two binomial RF pulses and the 180.degree. RF pulse are equal and are approximately at least to the reciprocal value of four times the scalar coupling constant of lactic acid.

MR spectroscopy method

The invention relates to a volume selective magnetic resonance spectroscopy method. Volume selection is performed after excitation by means of three layer-selective 180.degree. rf pulses which excite the nuclear magnetization in three mutually perpendicular layers. The distance between the three selective 180.degree. rf pulses can be chosen to be as small as possible.

Magnetic resonance spectroscopy method

The invention relates to a method of generating a selective 180.degree. rf pulse is formed by means of two selective 90.degree. rf pulses. Halfway between the two rf pulses there is generated a non-selective 180.degree. rf pulse which ensures that the excited nuclear magnetization is independent of the homogeneity of the steady magnetic field of the magnetic resonance examination apparatus.

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Zurich, Switzerland

Graeme C McKinnon