EP2979105A1 - Verfahren der magnetresonanz mit anregung durch einen prewinding pulse - Google Patents
Verfahren der magnetresonanz mit anregung durch einen prewinding pulseInfo
- Publication number
- EP2979105A1 EP2979105A1 EP14724323.2A EP14724323A EP2979105A1 EP 2979105 A1 EP2979105 A1 EP 2979105A1 EP 14724323 A EP14724323 A EP 14724323A EP 2979105 A1 EP2979105 A1 EP 2979105A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pulse
- prewinding
- echo
- excitation
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/561—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/46—NMR spectroscopy
- G01R33/4616—NMR spectroscopy using specific RF pulses or specific modulation schemes, e.g. stochastic excitation, adiabatic RF pulses, composite pulses, binomial pulses, Shinnar-le-Roux pulses, spectrally selective pulses not being used for spatial selection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/50—NMR imaging systems based on the determination of relaxation times, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
Definitions
- MR magnetic resonance
- NMR nuclear magnetic resonance
- MRI magnetic resonance tomography
- MRI MR imaging
- MR imaging MR imaging
- Imperfections of a square pulse used for conventional excitation are Imperfections of a square pulse used for conventional excitation.
- reference [14] describes a method in which the signal readout is read out intermittently during a radio-frequency pulse used for the excitation. This is achieved by dividing the excitation pulse into a grid of very short individual pulses. In other words, this is a method of measuring the MRI which is technically completely different from the above-described spin-echo method which is generic to the present invention.
- Magnetic resonance - hereinafter referred to as MR - is based on the measurement of the transverse magnetization of a sample, which is brought into an external magnetic field.
- Probe ' is used here as a generic term and can mean both a sample to be analyzed and - at
- the excited spins precess according to the Larmor condition with a
- Receiving coils located in the sensitive volume of the receiving coil signal which is formed as the sum of the transverse magnetization of the excited spins. Due to inhomogeneities of the
- reference [15] describes a method of generating a transverse magnetization that exhibits a constant phase.
- T2 * is typically in the range of 5 to 100 ms for measurements in MR tomography.
- T2 * is typically in the range of 5 to 100 ms for measurements in MR tomography.
- Symmetrical pulses with a simple profile corresponds to the dephasing of the free dephasing accumulated during the pulse over half the pulse duration.
- the local field inhomogeneity is caused on the one hand by technical inhomogeneities of the magnet used, on the other hand by different susceptibilities of the materials or tissue contained in the sample.
- the measurement of T2 * can therefore provide important information about the tissue properties.
- Dephased isochromates can be rephased by spin-echo formation (see reference [5]).
- a time t TE / 2
- Refocusing pulse is used, which is the accumulated phase of
- Isochromats inverted Upon further phase evolution according to their respective frequencies, all isochromats are rephased at echo time TE and a spin echo is formed. This refocussing is possible only for the static part T2 ', a refocusing of the T2 decay is fundamentally impossible.
- TSE Trobo Spin-Echo
- FSE Fast spin echo
- the spin-echo formation by Hahn pulses is also subject to limitations.
- the application of a refocussing pulse requires a certain minimum time (typically 1 to 5 ms in human MRI applications), so the minimum echo time is limited.
- the refocusing pulse causes Magnetization also inverted.
- MR tomography method which on several suggestions with a
- T1 for biological tissues is in the range of 0.5 to 2 s
- spin-echo experiments are usually performed with TR of about 0.5 to 10 s.
- Reception coils read out.
- the necessary spatial coding in order to be able to assign the measurement signal to a location within the object to be imaged takes place via additional, spatially varying, magnetic fields B z (x, y, z, t) which are superimposed on the main static magnetic field B 0 and cause
- Atomic nuclei at different locations have different Larmorfrequenzen. Conventionally, magnetic fields with a linear change in the strength along the respective spatial direction are used here,
- the 1, 2 or 3-dimensional spatial coding takes place under variation the magnetic field gradients in all three spatial directions according to known principles, such as Fourier coding, filtered back-projection or other known method.
- known principles such as Fourier coding, filtered back-projection or other known method.
- time-variable magnetic field gradients and RF pulses are superimposed on a stationary magnetic field.
- the present invention is based on the object to introduce an MR method of the type described above, which performs the following: 1.) generating a spin echo with a single pulse, which the
- the excitation pulse is a so-called "prewinding pulse” is used, which is characterized in that the transverse magnetization formed ⁇ ⁇ ( ⁇ ) of spins different
- Larmor frequency ⁇ after the excitation pulse have a phase ⁇ 0 ( ⁇ ), where ⁇ 0 ( ⁇ ) as a function of ⁇ within a predefined
- Frequency range Aco has an approximately linear course with a negative slope, so that the spins refocus after a defined by the excitation pulse echo time after the end of the excitation pulse, which is greater than the duration of the excitation pulse, without an additional
- the spin-echo formation takes place in 4 phases during a tap pulse:
- the refocusing pulse acts as a symmetry operator, the spin-echo formation occurs automatically due to the temporal symmetry of the phase evolution of the spins in the FID and the rephasing.
- the spin-echo formation depends only on the pulse spacing TE / 2, not on the off-resonance ⁇ . Of course, the range of detected spins can be limited by using selective pulses.
- the pulse sequence 90 ° -180 ° produces the largest echo. Small flip angles - both for the excitation and for the
- SNR signal to noise ratio
- a total flip angle (sum of excitation and refocusing pulse) of ⁇ »0 is required.
- signal saturation occurs.
- Hahn pulses are therefore not suitable for fast biotesting with short TR.
- the spin-echo formation is not based on a symmetry operation.
- the echo time is therefore not exclusively dependent on the distance between the excitation and refocusing pulses.
- the "prewinding pulse” is calculated using the Shinnar-Le Roux method, first solving the linear inversion problem, then fitting the solution to the nonlinear Bloch equation, so that This provides better control over the generated pulse profiles than the linear approximation, and also allows the pulse profile to be optimized in terms of secondary parameters such as pulse duration, maximum amplitude and others. Also advantageous is an alternative variant of the above method, which is characterized in that the calculation of the "prewindinginstalles" takes place by means of the optimal control method
- Optimization method ensures the exact fulfillment of the non-linear Bloch equation using Lagrange multipliers. This method is theoretical, as well as very complex in terms of computational time, but allows free control over all relevant parameters.
- An embodiment of the invention which is particularly suitable for imaging methods is characterized in that the readout of the generated signal is carried out with the aid of temporally variable magnetic field gradients in a 1, 2 or 3-dimensional location-coded manner, the locus coding being based on one of the known from the prior art imaging methods (such as
- a further embodiment of the present invention provides that the self-refocused signal is read out in a delayed manner-measured in terms of the echo time-and thus undergoes a defined, freely selectable T2 * -dependent modulation of amplitude and / or phase.
- this corresponds to a gradient-echo method, but on the other hand allows the read-out in the state of complete coherence of the isochromats, ie without T2 * -dependent dephasing.
- the two abovementioned embodiments of the invention can be developed advantageously in that the signal formed is read in or out several times by means of single or multiple gradient reversal at incremental readout times.
- Readout of the signal formed takes place under a read gradient GR.
- a further preferred variant of the invention is characterized in that both the "prewinding pulse" and the signal formed take place under a spatial encoding gradient GR and, if appropriate, a repetition of the recording takes place in a different spatial direction for 2-dimensional or 3-dimensional radial spatial coding Pulses are already at the edge of the k-space, so that it is directly readable radially, a gradient reversal is not required, resulting in a time saving, as well as a reduction in the temporal change of the magnetic field caused peripheral nerve stimulation
- Another alternative variant of the invention is characterized in that both the "prewinding pulse" and the signal formed under a
- the signal can be read out immediately after the end of the excitation pulse (possibly after the end of the phase coding), without the read-out gradient having to be reversed.
- the "prewinding pulse" is under a time-varying Gradients according to the VERSE method is used. This includes, among other things, the possibility to reduce B1 peaks. Alternatively, parts of the pulse with low B1 fields can be shortened and thus shorter pulses can be generated.
- the method can also be used as spatio-spectral pulses.
- Visual selective pulses are usually kept constant
- Everybody has a linear magnetic field gradient
- Position and off-resonance can not be clearly separated.
- spatial position and spectral frequency can be separated (see reference [8]). This concept can be applied to pulses according to the invention in order to achieve the desired frequency response via the magnetic field inhomogeneities ⁇ and at the same time to excite only a part of the sample.
- the excitation pulse can be selected such that it initially leads the magnetization to flip angles given by a z ⁇ a (t) ⁇ - ⁇ ⁇ .
- the magnetization collects a phase ramp dcp / doo which is amplified and inverted at the end of the pulse by passing the magnetization to the smaller target flip angle a z .
- the excitation pulse can be chosen such that Rmax (a) ⁇ Rmax (90 °) is achieved with a negative sign, or if the excitation pulse has a constant amplitude and has one or more phase jumps given limited maximum pulse amplitude. or that the amplitude of the
- Show it; 1 a is a diagram of the pulse sequence of a spin (Hahn) echo sequence in which the excitation pulse (exc) is a rectangular pulse of negligible length.
- the accumulated phase ramp is from the
- FIG. 1b shows the pulse diagram as in FIG. 1a, but with a sinc pulse of finite length. Already at the end of the pulse the spins have one
- FIG. 3a shows exemplary pulses calculated according to the invention in small angle approximation by regularized matrix inversion. If a larger regularization parameter is chosen, the energy of the B-j field is reduced.
- Fig.3b-d the frequency response of the pulses according to the invention.
- finish area the finish area
- the magnetization has a negative phase ramp (c).
- FIG. 4 shows an example sequence for using the prewinding pulse in FIG.
- Rf denotes the prewinding pulse Pprew, which in this case affects the entire sample, and the self-refocused signal generated after TE, GR the read, and GP1 and GP2 the two phase-encoding gradients.
- 5a shows a sequence as in FIG. 4, but with a delayed readout for generating a signal with a defined and arbitrarily variable T2 * weighting.
- Fig. 5b is a sequence as in Figure 5a, but with multiple readout of
- Fig. 6a shows the use of the prewinding pulse Pprew in conjunction with a
- Fig. 6b is a sequence as in Fig.6a, but with location-coded reading of
- Fig. 7a shows a sequence in the pulse and readout of the signal under a
- the direction of GR can be varied so that the 2- or 3-dimensional k-space is scanned radially.
- the field of view corresponds to a sphere.
- FIG. 7b shows a sequence as in FIG. 7a, with the difference that the k-
- Target range ⁇ By the Fourier shift theorem, the echo formation takes place at different times, depending on the slope ⁇ 0 1 da>. In the case of a positive slope, the echo time is
- the solid line represents the real and the dashed line represents the imaginary part of the pulse.
- the solid line represents the absolute value and the dashed line represents the phase of the frequency response.
- Fig.10 the effect of the pulse of Fig.9.
- the magnetization is first tilted to the transverse plane where it dephases.
- a -90 ° pulse redirects magnetization back to the x-z plane.
- 11A shows the magnetization from FIG. 10 in a transversal representation for the 90 ° (-90 °) (M1) and the 90 ° (-uO °) pulse combination (M2).
- FIG. 11B shows the magnetization from FIG. 11A (90 ° (- 90 °) combination) according to FIG.
- Figure 11C shows the magnetization of Figure 11A (90 ° - (- 90 °) combination) after a
- FIG. 12B shows the part of FIG. 12A relevant to pulses according to the invention
- FIG. 13 shows a generic pulse, which is composed of a ⁇ 12 and a - ⁇ 12 pulse (a).
- ⁇ ⁇ ⁇
- the result is a flip angle of 0 for the on-resonant spin isochromats and a linear one Increase in the flip angle with the off-resonance frequency (b).
- the phase makes a jump of ⁇ , so that the isochromate pairs of ⁇ and - ⁇ as a function of its amount gradually
- the time of the maximum signal (echo) depends primarily on the available frequencies ⁇ .
- Fig. 15 shows the principle of pulses according to the invention:
- the phase spacing of the spins picked up in the vicinity of the equator (A) is amplified by the transition to smaller flip angles (B).
- B is additionally the
- a special excitation pulse is used, which over a desired frequency range ⁇ a dephasing of negative slope with respect to the frequency generated (d ⁇ p ü I ⁇ ⁇ 0).
- free precession rephases the spins and, without a refocusing pulse, forms a spin echo
- Echo time TE -d ⁇ p 0 1 ⁇ , which is thus defined by the pulse.
- Such a pulse referred to as 'phase pre-winding pulse' can be generated by solving the Bloch equation for the conditions mentioned, ignoring T1 and T2 relaxation in the following discussion and ignoring only the free precession of the magnetization in the presence of the static Magnetic field inhomogeneities, as well as by the time-variable ⁇ - ⁇ field of the
- J ⁇ ⁇ ' ⁇ , . ⁇ '), E is a matrix with the entries E ri: exp (ico k nAt) and x describes the searched pulse.
- w k stretches in enough small steps to fulfill the Nyquist criterion, over the frequency range ⁇ , in which the pulse should achieve the desired effect.
- the amount of the transverse magnetization results from the
- Control 1 which is optimized to minimize a cost function.
- the desired frequency response can be exactly met, or minimizing the distance to the desired frequency response.
- Bloch equation is ensured via a Lagrange multiplier.
- FIG. 3 (a) shows by way of example a solution in small angle approximation.
- Figure 3 (bd) shows the frequency response of the pulse calculated by Bloch simulations (see reference [9]).
- the target area is a local minimum with respect to the flip angle. Outside of this frequency range is
- Larmor frequencies can be achieved, for example, by additional parameters in the cost function (in all presented methods), or by Lagrange multipliers.
- a global prewinding pulse is used in conjunction with a three-dimensional Fourier spatial encoding.
- Rf shows the prewinding pulse Pprew and the echo formed after the time TE.
- GR corresponds to the read gradient for location coding along the freely selectable first location coordinate, GP1 and GP2 the phase encoding gradient in the other two orthogonal spatial directions. Substitution of the Pprew pulse by a conventional excitation pulse would correspond to a 3D gradient echo method.
- Sro is chosen to cover the entire range of field inhomogeneities
- the formed signal is refocused with respect to field inhomogeneities using Pprew.
- Pprew phase and amplitude modulated by inhomogeneity-related T2 * decay
- Imaging, spiral imaging, and others combine with the prewinding pulse of the invention.
- the time of spontaneous refocusing TE does not have to be
- S o is chosen to cover the range of the resonant frequency of water or fat.
- the formed signal is then at the echo time TE rephased only for the desired range (water or fat), signals of each unwanted area are dephased and - depending on
- the prewinding pulse Pprew is applied in the presence of a slice selection gradient with amplitude Amp. If the gradient is left constant unchanged after the end of the pulse (dotted line in FIG. 6a), then the self-refocusing takes place at time TE. Will the gradient be after the
- FIG. 6b shows the method illustrated in FIG. 6a in conjunction with FIG
- Spatial encoding gradient GR This is turned on at the time TE ', the signal is thus read out as a so-called half echo.
- the principle of radial spatial coding is advantageously used, with the direction of the readout gradient being continuously changed in successive acquisition steps.
- FIG. 7 shows an implementation of the method under a constant read gradient GR.
- the spectrum generated by Fourier transformation of the echo formed shows a constant phase over the frequency range ⁇ , where ⁇ over the gradient GR corresponds to an area Ar in the spatial domain. ⁇ is chosen so that Ar is symmetrical about the zero point of the gradient. If repetition of recording under continuous
- GR can be left constant in one direction.
- a layer is excited whose thickness results from ⁇ and the gradient strength.
- the remaining two spatial directions can be coded with phase coding between excitation and data readout (Fig.7b).
- the reading gradient GR can either remain switched on or be switched off for a short time.
- the echo time is a function of the area under GR.
- Modulation of the frequency ranges outside of ⁇ employ.
- a further preferred realization of a pulse according to the invention should initially be explained by a generic pulse which is composed of two hard pulses. Subsequently, the transition to more practical pulses is presented, including an estimation of the possibilities and limits of pulses according to the invention.
- the z-magnetization (Fig.l OA) is first rotated by RF- ⁇ on the y-axis (Fig. L OB). The
- FIGS. 1 and 12A shows the dependence of the echo time TE on the pulse duration tp.
- Fig. 12B shows the echo amplitude 11 (TE) as a function of ⁇ .
- the signal intensity is quite small.
- An increase of the echo amplitude can easily be achieved by choosing the amount of a 2 > 90 ° (a 2 thus less than -90 °).
- the pulse from FIG. 13 can be modified to a ⁇ / 2 - (- / 2 - 0.2) (FIG. 4).
- the resulting flip angle for all isochromats is greater than zero and the phase has no jump, but a continuous ramp.
- the above-mentioned factor R can also be described on the basis of the slope of the phase as a function of the frequency:
- the aforementioned principle of the pulses according to the invention can be generally described by saying that the magnetization is not guided directly to the desired target flip angle a z but to flip angles a (t) given by a z ⁇ a (t) ⁇ - ⁇ ⁇ are. At these flip angles, the spins dephase.
- Dephasing can be enhanced by the transition to smaller flip angles a z , as shown below. If the magnetization ramp dcp / doa is inverted, a spin echo is produced at the end of the pulse.
- the echo time is not limited to the bottom, since no complete dephasing is required (see Hahn echoes). As will be shown below, the echo time (measured from the end of the pulse) is not limited to TE ⁇ T P as long as the target flip angle a z ⁇ I 2 is selected. T P describes the length of the pulse.
- Isochromates in the sense of the Euclidean norm can thus only be achieved by precession of the spins as a result of their different Larmor frequencies and is thus only indirectly influenced.
- Pulses according to the invention exploit the described effect by initially leading magnetization to flip angles close to ⁇ 1 2, where a large Euclidean distance between the isochromates rapidly arises.
- Phase ramp is inverted.
- the negative phase ramp then leads automatically through free precession to a spin echo whose timing is given by the slope of the phase ramp.
- the pulse duration is 0.5 ms.
Landscapes
- Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102013205528.5A DE102013205528B3 (de) | 2013-03-27 | 2013-03-27 | Verfahren der Magnetresonanz mit Anregung durch einen prewinding pulse |
PCT/EP2014/054328 WO2014154461A1 (de) | 2013-03-27 | 2014-03-06 | Verfahren der magnetresonanz mit anregung durch einen prewinding pulse |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2979105A1 true EP2979105A1 (de) | 2016-02-03 |
Family
ID=50732104
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP14724323.2A Withdrawn EP2979105A1 (de) | 2013-03-27 | 2014-03-06 | Verfahren der magnetresonanz mit anregung durch einen prewinding pulse |
Country Status (4)
Country | Link |
---|---|
US (1) | US10281548B2 (de) |
EP (1) | EP2979105A1 (de) |
DE (1) | DE102013205528B3 (de) |
WO (1) | WO2014154461A1 (de) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9791530B2 (en) | 2012-04-14 | 2017-10-17 | The Regents Of The University Of Michigan | Method of MRI imaging using non-slice-selective, spatially tailored tip-up pulse |
US10247801B2 (en) | 2014-04-25 | 2019-04-02 | The Regents Of The University Of Michigan | Method of MRI imaging using a spectrally designed pulse |
DE102014221950B3 (de) * | 2014-10-28 | 2016-04-21 | Siemens Aktiengesellschaft | Geräuschreduzierung bei selektiver MR-Anregung |
US10338178B2 (en) * | 2015-01-12 | 2019-07-02 | The Board Of Trustees Of The University Of Illinois | System and method for high-resolution spectroscopic imaging |
US10429463B2 (en) * | 2016-06-13 | 2019-10-01 | Toshiba Medical Systems Corporation | Quiet MRI with spin echo (SE) or fast spin echo (FSE) |
US11041925B2 (en) * | 2016-10-06 | 2021-06-22 | Koninklijke Philips N.V. | Direct measurement of the B0-off-resonance field during magnetic resonance fingerprinting |
US10641855B2 (en) * | 2016-11-02 | 2020-05-05 | The Board Of Trustees Of The Leland Stanford Junior University | Methods for mitigating local SAR hotspots and flip angle uniformity in ultra-high field simultaneous multislice imaging using parallel transmission |
US11079453B2 (en) | 2017-08-30 | 2021-08-03 | The Board Of Trustees Of The University Of Illinois | System and method for ultrafast magnetic resonance spectroscopic imaging using learned spectral features |
EP3537168B1 (de) * | 2018-03-08 | 2022-01-05 | Siemens Healthcare GmbH | Verfahren zur aufnahme von magnetresonanzdaten für die quantitative magnetresonanzbildgebung, magnetresonanzeinrichtung, computerprogramm und elektronisch lesbarer datenträger |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4947119A (en) * | 1988-06-21 | 1990-08-07 | University Of Minnesota | Magnetic resonance imaging and spectroscopy methods |
US5280245A (en) * | 1992-07-27 | 1994-01-18 | Board Of Trustees Of The Leland Stanford Junior Unversity | Magnetic resonance apparatus employing delayed self-refocusing RF excitation |
US5619138A (en) * | 1995-08-21 | 1997-04-08 | National Research Council Of Canada | Method of providing an RF pulse for use in NMR |
US5820245A (en) * | 1995-12-11 | 1998-10-13 | Donnelly Corporation | Rearview mirror assembly |
US7166998B2 (en) * | 2003-12-12 | 2007-01-23 | The Trustees Of The University Of Pennsylvania | Exact half pulse synthesis via the inverse scattering transform |
US7425828B2 (en) * | 2005-10-11 | 2008-09-16 | Regents Of The University Of Minnesota | Frequency swept excitation for magnetic resonance |
DE102008014060B4 (de) * | 2008-03-13 | 2010-06-17 | Siemens Aktiengesellschaft | Verfahren zur Bestimmung einer Phasenlage einer Magnetisierung und Magnetresonanzanlage |
US9494668B2 (en) * | 2011-12-02 | 2016-11-15 | The Johns Hopkins University | Systems and methods for measuring nuclear magnetic resonance spin-lattice relaxation time T1 and spin-spin relaxation time T2 |
US9791530B2 (en) * | 2012-04-14 | 2017-10-17 | The Regents Of The University Of Michigan | Method of MRI imaging using non-slice-selective, spatially tailored tip-up pulse |
DE102013201616B3 (de) * | 2013-01-31 | 2014-07-17 | Siemens Aktiengesellschaft | TSE-basierte, gegen lokale B0-Feldvariationen unempfindliche MR-Mulitschicht-Anregung |
US11137466B2 (en) * | 2014-12-15 | 2021-10-05 | Koninklijke Philips N.V. | Spin echo MR imaging |
-
2013
- 2013-03-27 DE DE102013205528.5A patent/DE102013205528B3/de not_active Expired - Fee Related
-
2014
- 2014-03-06 EP EP14724323.2A patent/EP2979105A1/de not_active Withdrawn
- 2014-03-06 WO PCT/EP2014/054328 patent/WO2014154461A1/de active Application Filing
- 2014-03-06 US US14/652,129 patent/US10281548B2/en not_active Expired - Fee Related
Non-Patent Citations (2)
Title |
---|
None * |
See also references of WO2014154461A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102013205528B3 (de) | 2014-08-28 |
US20150323631A1 (en) | 2015-11-12 |
WO2014154461A1 (de) | 2014-10-02 |
US10281548B2 (en) | 2019-05-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
DE102013205528B3 (de) | Verfahren der Magnetresonanz mit Anregung durch einen prewinding pulse | |
DE102008014060B4 (de) | Verfahren zur Bestimmung einer Phasenlage einer Magnetisierung und Magnetresonanzanlage | |
DE112014004240B4 (de) | MRI mit Wasser-/Fettseparation vom Dixon-Typ und mit unterschiedlichen Auflösungen erfassten Echos zur Wirbelstromkorrektur | |
DE102011007501B3 (de) | Verfahren der bildgebenden Magnetresonanz zur Selektion und Aufnahme von gekrümmten Schichten | |
EP0496501B1 (de) | Bilderzeugung mittels magnetischer Resonanz von Untersuchungsarten mit kurzer T2 mit verbessertem Kontrast | |
DE102011004881B4 (de) | Verarbeiten von komplexen Bilddaten eines Untersuchungsobjekts mit unterschiedlichen Spin-Spezies in der MR-Bildgebung | |
DE102011083619B4 (de) | Verfahren zur Erzeugung einer Serie von MR-Bildern zur Überwachung einer Position eines in einem Untersuchungsgebiet befindlichen Interventionsgeräts, Magnetresonanzanlage und elektronisch lesbarer Datenträger | |
DE102015221888B4 (de) | Gleichzeitige MRT-Mehrschichtmessung | |
DE102014210778A1 (de) | Erzeugung einer Parameterkarte in der Magnetresonanztechnik | |
DE112015006200T5 (de) | System und Verfahren für Delta-Relaxationsverstärkte Magnetresonanztomographie | |
DE102015205693A1 (de) | Geschwindigkeitskompensierte diffusionssensibilisierte Diffusionsbildgebung | |
WO2016058876A2 (de) | Verfahren zur erstellung einer mrt-aufnahme | |
DE102012206493B3 (de) | Magnetresonanz-Bildgebungsverfahren mit optimierter Hintergrundphasenverteilung | |
DE102004021771B4 (de) | Verfahren zur dynamischen Detektion der Resonanzfrequenz in Magnetresonanz-Spektroskopie-Experimenten | |
DE102005015069A1 (de) | Verfahren zur Vermeidung linearer Phasenfehler in der Magnetresonanz-Spektroskopie | |
DE102010041450A1 (de) | Verfahren zur automatischen Erstellung eines selektiven MR-Bildes, Magnetresonanzanlage, Computerprogrammprodukt sowie elektronisch lesbarer Datenträger | |
DE102013227170B3 (de) | Verfahren und Steuereinrichtung zur Ansteuerung eines Magnetresonanzsystems | |
DE102015219932B4 (de) | Beschleunigte Aufnahme von Magnetresonanzdaten | |
EP0396710A1 (de) | Verfahren zum selektiven anregen von nmr-signalen. | |
DE19962846A1 (de) | Bildgebungsverfahren | |
EP3796023A1 (de) | Verbessertes magnetresonanz-dixon-verfahren | |
DE102015208939B4 (de) | Bestimmung von zeitabhängigen Dephasierungsfaktoren bei MR-Signalen | |
EP1740968B1 (de) | Bildgebungsverfahren sowie kernspintomograph zur erfassung der longitudinalen spin-gitter relaxationszeit | |
DE19962850B4 (de) | Spektroskopisches Bildgebungsverfahren | |
DE102015223658B4 (de) | Verfahren zum Erfassen von Magnetresonanz-Signalen eines Untersuchungsobjekts |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20151027 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: GLASER, STEFFEN Inventor name: ASSLAENDER, JAKOB Inventor name: HENNIG, JUERGEN |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: UNIVERSITAETSKLINIKUM FREIBURG |
|
DAX | Request for extension of the european patent (deleted) | ||
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: GRANT OF PATENT IS INTENDED |
|
INTG | Intention to grant announced |
Effective date: 20200506 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: UNIVERSITAETSKLINIKUM FREIBURG |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20200917 |