By Scanning Sample Frequency Spectrum Patents (Class 324/310)
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Patent number: 8082127Abstract: A method for determining the spatial distribution of magnetic resonance signals from an imaging area, wherein nuclear spins are excited in a spatially encoded fashion through multi-dimensional RF pulses, is characterized in that in a definition step, a resolution grid with resolution grid cells is predetermined, and in accordance with a predetermined phase encoding scheme, an excitation pattern is defined for each phase encoding step, in which the amplitudes within the imaging area are set in accordance with a predetermined distribution identically for each phase encoding step. In a preparatory step, the amplitude and phase behavior of the RF pulses to be irradiated is calculated in accordance with a predetermined k-space trajectory for each defined complex excitation pattern.Type: GrantFiled: September 13, 2008Date of Patent: December 20, 2011Assignee: Bruker BioSpin MRI GmbHInventor: Wolfgang Ruhm
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Publication number: 20110084693Abstract: Methods and systems in a parallel magnetic resonance imaging (MRI) system utilize sensitivity-encoded MRI data acquired from multiple receiver coils together with spatially dependent receiver coil sensitivities to generate MRI images. The acquired MRI data forms a reduced MRI data set that is undersampled in at least a phase-encoding direction in a frequency domain. The acquired MRI data and auto-calibration signal data are used to determine reconstruction coefficients for each receiver coil using a weighted or a robust least squares method. The reconstruction coefficients vary spatially with respect to at least the spatial coordinate that is orthogonal to the undersampled, phase-encoding direction(s) (e.g., a frequency encoding direction).Type: ApplicationFiled: December 17, 2010Publication date: April 14, 2011Applicant: UNIVERSITY OF UTAH RESEARCH FOUNDATIONInventors: Evgueni G. Kholmovski, Dennis Lee Parker
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Patent number: 7924007Abstract: In a method for coil selection of a magnetic resonance apparatus, a determination of coil positions of the multiple coil devices of the magnetic resonance apparatus is made and a determination is also made of a number of coil groups, wherein a coil group is composed of at least one coil device. One or more coil groups is associated with positions of the support device, and the coil group that is associated with a position of the support device includes the coil devices that are suitable for use in that associated position of the support device. A control of one of the multiple coil groups dependent on the position of the support device.Type: GrantFiled: February 28, 2008Date of Patent: April 12, 2011Assignee: Siemens AktiengesellschaftInventors: Thomas Arnold, Swen Campagna
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Publication number: 20110062958Abstract: In a combined imaging system, including a magnetic resonance system and a UWB radar, interference signals in the received signal of the one imaging system can be caused by the respective other imaging system. Therefore filters which contain in particular adaptive filters are used in order to filter out the interference signals caused in the received signal of the one system by the respective other system. By eliminating the mutually negative influence, the advantages can be completely exploited when operating the different imaging systems at the same time.Type: ApplicationFiled: September 3, 2010Publication date: March 17, 2011Inventor: Wilfried Schnell
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Publication number: 20110050228Abstract: An agent for magnetic resonance studies, the agent comprising hyperpolarized 15N labelled N2O in solution or liquid 15N—N2O.Type: ApplicationFiled: March 10, 2009Publication date: March 3, 2011Applicant: University of SouhamptonInventors: Malcolm Harris Levitt, Giuseppe Pileio
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Publication number: 20110050227Abstract: Systems and methods are provided for controlling coherence of a magnetic resonance signal of spin species. The small difference between hard ? pulses and their delta-function approximation is exploited to provide new classes of spin echoes which have applications in nuclear magnetic resonance (NMR) spectroscopy, magnetic resonance imaging (MRI) and magnetic resonance microscopy (MRM), and related spectroscopies of solids, and mixtures of solids and liquids. Systems and methods are also provided for controlling coherence of the resonance signal from pseudospin species.Type: ApplicationFiled: September 5, 2008Publication date: March 3, 2011Inventors: Sean E. Barrett, Yanqun Dong, Rona G. Ramos, Dale Li
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Patent number: 7884604Abstract: Methods and systems in a parallel magnetic resonance imaging (MRI) system utilize sensitivity-encoded MRI data acquired from multiple receiver coils together with spatially dependent receiver coil sensitivities to generate MRI images. The acquired MRI data forms a reduced MRI data set that is undersampled in at least a phase-encoding direction in a frequency domain. The acquired MRI data and auto-calibration signal data are used to determine reconstruction coefficients for each receiver coil using a weighted or a robust least squares method. The reconstruction coefficients vary spatially with respect to at least the spatial coordinate that is orthogonal to the undersampled, phase-encoding direction(s) (e.g., a frequency encoding direction).Type: GrantFiled: March 30, 2009Date of Patent: February 8, 2011Assignee: University of Utah Research FoundationInventors: Evgueni G. Kholmovski, Dennis Lee Parker
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Patent number: 7880468Abstract: The present invention presents a new approach to rapidly obtaining precise high-dimensional NMR spectral information, named “GFT NMR spectroscopy”, which is based on the phase sensitive joint sampling of the indirect dimensions spanning a subspace of a conventional NMR experiment. The phase-sensitive joint sampling of several indirect dimensions of a high-dimensional NMR experiment leads to largely reduced minimum measurement times when compared to FT NMR. This allows one to avoid the “sampling limited” data collection regime. Concomitantly, the analysis of the resulting chemical shift multiplets, which are edited by the G-matrix transformation, yields increased precision for the measurement of the chemical shifts. Additionally, methods of conducting specific GFT NMR experiments as well as methods of conducting a combination of GFT NMR experiments for rapidly obtaining precise chemical shift assignment and determining the structure of proteins or other molecules are disclosed.Type: GrantFiled: March 27, 2008Date of Patent: February 1, 2011Assignee: The Research Foundation of State University of New YorkInventors: Thomas A. Szyperski, Seho Kim, Hanudatta S. Atreya
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Publication number: 20110018535Abstract: A method for mineral analysis of a sample based on detection of NQR and/or NMR signals from a particular substance within a sample includes: setting a frequency of RF pulses to be approximately equal to one of the NQR or NMR frequencies of the substance; setting a set of parameters of the RF pulses to be optimal for the substance; setting a set of receiving parameters to be optimal for the substance; tuning the probe to maximum sensitivity for the signals detected at predetermined frequency and/or to maximum power transfer efficiency for RF pulses transmitted with the probe; transmitting the RF pulses with the probe at said optimal level during a transmitting period to irradiate the sample and excite an NQR or NMR signal in the substance, if present; detecting and processing NQR or NMR signals emitted by the substance; and calculating the concentration of the substance in the sample.Type: ApplicationFiled: July 23, 2010Publication date: January 27, 2011Inventor: Taras Rudakov
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Publication number: 20100331403Abstract: The present invention provides methods of synthesizing organic arsenicals. Many of these compounds have potent in vitro cytotoxic activity against numerous human tumor cell lines, both of solid and hematological origin, as well as against malignant blood cells from patients with leukemia.Type: ApplicationFiled: December 12, 2008Publication date: December 30, 2010Inventors: John C. Amedio, JR., Frank Walter Waligora
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Publication number: 20100259263Abstract: Devices, systems, and techniques relate to detecting volumetric changes in imaged structures over time, including devices, systems and techniques that enable precise registration of structures (e.g., brain areas) after large or subtle deformations, allowing precise registration at small spatial scales with a low boundary contrast.Type: ApplicationFiled: November 14, 2008Publication date: October 14, 2010Inventors: Dominic Holland, Anders M. Dale
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Publication number: 20100244834Abstract: A magnetic resonance imaging (MRI) system, comprising: a MRI scanner; a signal processing system in communication with the magnetic resonance imaging scanner to receive magnetic resonance (MR) signals for forming magnetic resonance images of a subject under observations; a data storage unit in communication with the signal processing system, wherein the data storage unit contains database data corresponding to a soft tissue region of the subject under observation. The database data includes information identifying at least one soft tissue substructure encompassed by the soft tissue region of the subject under observation. The signal processing system is adapted to process MR signals received from the MRI scanner to automatically identify at least one soft tissue substructure encompassed by the soft tissue region of the subject under observation.Type: ApplicationFiled: January 5, 2009Publication date: September 30, 2010Applicant: THE JOHNS HOPKINS UNIVERSITYInventors: Susumu Mori, Jiangyang Zhang, Kegang Hua
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Publication number: 20100227755Abstract: A method of evaluating kneaded clay includes, preparing kneaded clay by mixing and kneading at least ceramic raw material and water as contained materials, measuring T1 relaxation time and/or T2 relaxation time of proton contained in the contained materials by NMR method, and evaluating a kneaded state of the kneaded clay. There is further provided a method for manufacturing kneaded clay, wherein the kneaded clay is kneaded by using the method for evaluating kneaded clay while checking the kneaded state.Type: ApplicationFiled: February 17, 2010Publication date: September 9, 2010Applicant: NGK Insulators, Ltd.Inventor: Takao SAITO
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Publication number: 20100201362Abstract: We describe a method for use in enhancing MRI signals and increasing the sensitivity of NMR spectroscopy. The method involves the use of dynamic nuclear polarization (DNP) in which the polarizing agents are sequestered at the interface between two phases a sample phase, and a polarizing phase in such a way that the polarizing agent can be easily removed from the sample prior to analysis. The method produces much efficiency for sample manipulation, and the polarization process. In at least one embodiment the hyper-polarization can be repeated so as to allow the accumulation of spectra of the same material for further increasing the signal to noise ratio. The method also allows a discernment of which peaks in an NMR spectrum of a mixture belong to each individual component.Type: ApplicationFiled: February 11, 2010Publication date: August 12, 2010Inventor: Bruce Holman, III
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Publication number: 20100156418Abstract: In order to stably obtain an even fat-suppressed image without reduction of an imaging efficiency and without being affected by unevenness of irradiation magnetic field of an RF pulse, when an imaging sequence having a first sequence part for suppressing a signal from a desired component of an examinee by applying a CHESS pulse and a second sequence part for measuring an echo signal from the examinee is repeated, the flip angle of the CHESS pulse is changed at plural times. In the case of multi-slice imaging, the flip angle of the CHESS pulse is changed in at lest two slice imaging.Type: ApplicationFiled: June 25, 2008Publication date: June 24, 2010Applicant: HITACHI MEDICAL CORPORATIONInventors: Takayuki Abe, Hiroyuki Takeuchi, Tetsuhiko Takahashi
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Publication number: 20100148776Abstract: An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for processing the signal data, using means including a digital signal processor.Type: ApplicationFiled: June 28, 2007Publication date: June 17, 2010Applicant: THE GOV'T OF THE U.S., REPRESENTY BY THE SECRETARY OF THE DEPT OF HEALTH AND HUMAN SERVICESInventors: Sankaran Subramanian, Nallathamby Devasahayam, Janusz Koscielniak, James B. Mitchell, Murali Krishna Cherukuri
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Publication number: 20100127705Abstract: A method and an apparatus for magnetic induction tomography, in which an object with inhomogeneous passive electrical properties is exposed to an alternating magnetic field by excitation coils located at different positions, from which receiver coils located at different positions pick up AC signals which contain information concerning the electrical conductivity and its distribution in the object, and images of the spatial electrical properties in the interior of the object are reconstructed from the amplitudes and phases of the received signals, whereas the measurement is carried out at least 2 frequencies and an additional perturbation of the coils and/or the field geometry so as to determine a correction factor with which it is possible to widely eliminate spurious signals generated by changes of the geometry during the object measurement.Type: ApplicationFiled: July 24, 2007Publication date: May 27, 2010Applicants: Technische Universitat Graz, Forschungsholding TU Graz GmbHInventor: Hermann Scharfetter
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Publication number: 20100117647Abstract: Embodiments of the present invention relate to accelerated dynamic magnetic resonance imaging (MRI) and, more particularly, to imaging situations where the temporal-encoding strategy is disrupted by time-related events, such as breathing motion.Type: ApplicationFiled: December 10, 2007Publication date: May 13, 2010Inventor: Bruno Madore
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Publication number: 20100097062Abstract: A method for obtaining the most appropriate amplitude of signal suppression pulse, which suppresses unnecessary signals from the substance not subjected to measurement, highly accurately, swiftly and stably, and an MRI apparatus that enables the optimization are provided. A pulse amplitude adjusting means equipped in the MRI apparatus acquires signals while changing the amplitude of signal suppression pulse and calculates signal absolute values and phase values, and computes reference signals, which are polarized signal absolute values, based on the changes in signal phase values. This reference signals are subjected to polynomial fitting. A value which makes this fitting curve is 0 or closes to 0 is set as the optimal pulse amplitude.Type: ApplicationFiled: June 29, 2007Publication date: April 22, 2010Inventors: Toru Shirai, Yoshitaka Bito, Yo Taniguchi, Satoshi Hirata
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Publication number: 20100066366Abstract: This method of adaptive signal averaging is used to enhance the signal to noise ratio of magnetic resonance and other analytical measurements which involve repeatable signals partially or completely obscured by noise in a single measurement at a rate much faster than that observed with conventional signal averaging. This technique expedites the signal averaging process because it filters each individual scan in real time with an adaptive algorithm and then averages them separately to provide an averaged filtered signal with less noise. This technique is particularly useful for any type of continuous wave magnetic resonance experiment or any other noisy measurement where signal averaging is utilized.Type: ApplicationFiled: September 10, 2009Publication date: March 18, 2010Applicant: The Penn State Research FoundationInventors: Corey Cochrane, Patrick M. Lenahan
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Publication number: 20100039110Abstract: An MRI apparatus capable of performing a high-speed operation for removing aliasing from the data measured by non-Cartesian imaging in a real space with a small amount of operation is provided. Non-Cartesian data sampling is performed by thinning the number of data by using multiple receiver coils having different sensitivity distribution from each other. Image reconstruction means creates orthogonal data by gridding non-orthogonal data obtained by each receiver coil on a grid having an equal spatial resolution to and a narrower field of view than a target image, subjects it to Fourier transform and creates the first image data containing aliasing components. The second image data is created by using the first image data created for each receiver coil and a sensitivity distribution of each receiver coil.Type: ApplicationFiled: March 3, 2008Publication date: February 18, 2010Inventors: Tetsuhiko Takahashi, Masahiro Takizawa, Yasuhiro Kamada
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Patent number: 7663365Abstract: A magnetic resonance imaging apparatus includes an imaging unit which performs imaging more than once with respect to an imaging target while changing a central frequency of a fat suppression pulse, a generation unit which generates a plurality of images based on magnetic resonance signals obtained by imaging performed more than once, and a calculation unit which calculates factor information of spatial inhomogeneity of a fat suppression effect based on the plurality of images.Type: GrantFiled: September 24, 2008Date of Patent: February 16, 2010Assignees: Kabushiki Kaisha Toshiba, Toshiba Medical Systems CorporationInventor: Hitoshi Kanazawa
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Publication number: 20100033176Abstract: Viscosity of heavy oil is determined in situ in a formation by making nuclear magnetic resonance (NMR) measurements in the formation, and then calculating viscosity according to an equation of the form T 2 ? LM = a + b ? ( ? T ) c , where T is the temperature of the heavy oil sample, ? is the viscosity, T2LM is the logarithmic mean of the T2 distribution spectrum of the sample, and a, b, and c are non-zero constants. Typically, constant b has a value between 5 and 7 and constant c has a value between ?0.7 and ?0.5.Type: ApplicationFiled: July 28, 2009Publication date: February 11, 2010Inventors: Yuesheng Cheng, Abdel M. Kharrat
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Publication number: 20100001727Abstract: A method and apparatus for treating a sample for acquiring high-definition magnetic resonance images (MRI images) or high resolution nuclear magnetic resonance (NMR) spectra even in the presence of magnetic field distortions within one or multiple scans. The spatial nature and temporal dependence of the field inhomogeneities are determined a priori using any of several literature procedures. A static or oscillating magnetic field gradient is applied on the sample so as to endow spins at different positions within the sample with different resonance frequencies. A phase- and amplitude-modulated radiofrequency (RF) pulse is applied in unison with the magnetic field gradient so as to endow spins at different positions within the sample with a homogeneous excitation/inversion profile.Type: ApplicationFiled: December 14, 2006Publication date: January 7, 2010Inventors: Lucio Frydman, Boaz Shapira, Assaf Tal
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Patent number: 7642777Abstract: A fast automatic linear off-resonance correction method for MRI data uses a set of widely spaced demodulation frequencies to estimate a low-resolution field map from the image itself. A linear map is determined by fitting to this low-resolution map using a maximum-likelihood estimator with weights proportional to the pixel intensity.Type: GrantFiled: August 21, 2007Date of Patent: January 5, 2010Assignee: University of Virginia Patent FoundationInventors: Craig H. Meyer, Weitian Chen
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Patent number: 7634302Abstract: A method of differentiating tissues in Magnetic Resonance Imaging (MRI) comprising applying a Magnetization Transfer (MT) pre-pulse in combination with the Diffusion Weighted Imaging (DWI) pulse sequence to obtain an image of the tissue under evaluation. Analysis maps and/or measurements are generated from the obtained image, from which values representative of the macromolecular content are computed for obtaining tissue differentiation.Type: GrantFiled: July 9, 2004Date of Patent: December 15, 2009Assignee: General Electric CompanyInventors: Rakesh Kumar Gupta, Anasuya Mohan Rao, Ramesh Venkatesan
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Patent number: 7620440Abstract: An improved imaging technique and apparatus for direct temporal encoding of spatial information of an object is presented. The signal collected from the object after application of excitation energy in a magnetic field is directly representative of the spatial position of the object without the need for the signal to undergo mathematical transformation. This is a result of the excitation scheme that generates transverse magnetization across the field of view that is a function of X (read-out) and Z (slice select) positions, resulting in a two-dimensional phase profile that, upon application of a constant gradient along the Z axis, elicits a signal that is directly attributable to the spatial position along the read-out dimension without application of mathematical transformation.Type: GrantFiled: May 16, 2003Date of Patent: November 17, 2009Assignee: Case Western Reserve UniversityInventors: Daniel Elgort, Brian M. Dale, Jeffrey L. Duerk
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Publication number: 20090256563Abstract: Techniques and systems for magnetic resonance imaging. In one aspect, preparatory pulse sequences precede alternating repetition time steady state free precession (ATR SSFP) pulse sequences to enable image acquisition before reaching a steady-state equilibrium. The design of the preparatory sequences is based on a two step process: First an oscillatory residue is expressed in terms of a window (e.g., a Kaiser-Bessel window) and scale parameters. Second the oscillatory residue is minimized to determine the scale parameters according to a desired application (e.g. ATR SSFP, optimized for fat, water, etc.) The preparation scheme described in this specification can be applied to arbitrary repetition times and RF phase cycling combinations.Type: ApplicationFiled: March 2, 2009Publication date: October 15, 2009Applicant: UNIVERSITY OF SOUTHERN CALIFORNIAInventors: Hsu-Lei Lee, Krishna S. Nayak
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Publication number: 20090224759Abstract: Methods and systems in a parallel magnetic resonance imaging (MRI) system utilize sensitivity-encoded MRI data acquired from multiple receiver coils together with spatially dependent receiver coil sensitivities to generate MRI images. The acquired MRI data forms a reduced MRI data set that is undersampled in at least a phase-encoding direction in a frequency domain. The acquired MRI data and auto-calibration signal data are used to determine reconstruction coefficients for each receiver coil using a weighted or a robust least squares method. The reconstruction coefficients vary spatially with respect to at least the spatial coordinate that is orthogonal to the undersampled, phase-encoding direction(s) (e.g., a frequency encoding direction).Type: ApplicationFiled: March 30, 2009Publication date: September 10, 2009Inventors: Evgueni G. Kholmovski, Dennis Lee Parker
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Patent number: 7570985Abstract: Monitor scans are performed before imaging scans with respect to a patient injected with a contrast agent. Magnetic resonance images of a plurality of slices of the patient are acquired, usually continuously, in the monitor scans. Projection images are generated from the magnetic resonance images for the plurality of slices, and these projection images are dynamically displayed images. The operator observes the monitor image and issues an instruction for imaging scans. Since a projection image is displayed as the monitor image, then even if a blood vessel is distributed over a three-dimensional area, the operator is still able to ascertain accurately the timing at which the contrast agent reaches the diagnostic region.Type: GrantFiled: November 6, 2002Date of Patent: August 4, 2009Assignee: Kabushiki Kaisha ToshibaInventors: Naoyuki Takabayashi, Yutaka Fukushima
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Patent number: 7567081Abstract: Disclosed are methods and apparatuses for generating susceptibility-related contrast images, as induced, e.g., by marker material interventional devices used for passive MR-guided interventions, or by particles or cells loaded with marker materials used for molecular imaging, cell-tracking or cell-labeling. Near a local magnetic field perturber a positive contrast signal emanates from local gradient compensation to form, e.g., a balanced SSFP type of echo, whereas everywhere else echoes are shifted outside of the data acquisition window.Type: GrantFiled: May 3, 2007Date of Patent: July 28, 2009Assignee: University of BaselInventors: Oliver Bieri, Klaus Scheffler
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Patent number: 7535229Abstract: Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.Type: GrantFiled: April 26, 2007Date of Patent: May 19, 2009Inventors: Ross D. Schlueter, Thomas F. Budinger
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Patent number: 7535222Abstract: Disclosed is a new propeller EPI pulse sequence with reduced sensitivity to field inhomogeneities is proposed. Image artifacts such as blurring due to Nyquist ghosting and susceptibility gradients are investigated and compared with those obtained in previous propeller EPI studies. The proposed propeller EPI sequence uses a readout that is played out along the short axis of the propeller blade, orthogonal to the readout used in previous propeller methods. In contrast to long-axis readout propeller EPI, this causes the echo spacing between two consecutive phase-encoding (PE) lines to decrease, which in turn increases the k-space velocity in this direction and hence the pseudo-bandwidth.Type: GrantFiled: January 2, 2007Date of Patent: May 19, 2009Assignee: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Roland Bammer, Stefan T. Skare
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Patent number: 7514922Abstract: A magnetic resonance probe head (40) comprises a vacuum container (43) in which several RF resonator coils (31, 32; 51-54, 61-64) are disposed that can be cryogenically cooled and which are each designed as planar coils disposed parallel to a z direction. All of the RF resonator coils (31, 32; 51-54, 61-64) have a larger extension in an x direction (RSx) than in a y direction (RSy), wherein the x, y, z directions form a rectangular coordinate system. A central tube block (33; 81; 111; 121; 171; 181) is disposed between the RF resonator coils (31, 32; 51-54, 61-64) and has a recess (34, 112, 122) for a test sample (35), which is elongated in the z direction. The central tube block (33; 81; 111; 121; 171; 181) partially delimits the vacuum container and the recess (34, 112, 122) is disposed outside of the vacuum container (43).Type: GrantFiled: September 11, 2007Date of Patent: April 7, 2009Assignee: Bruker Biospin AGInventor: Nicolas Freytag
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Patent number: 7511495Abstract: Methods and systems in a parallel magnetic resonance imaging (MRI) system utilize sensitivity-encoded MRI data acquired from multiple receiver coils together with spatially dependent receiver coil sensitivities to generate MRI images. The acquired MRI data forms a reduced MRI data set that is undersampled in at least a phase-encoding direction in a frequency domain. The acquired MRI data and auto-calibration signal data are used to determine reconstruction coefficients for each receiver coil using a weighted or a robust least squares method. The reconstruction coefficients vary spatially with respect to at least the spatial coordinate that is orthogonal to the undersampled, phase-encoding direction(s) (e.g., a frequency encoding direction).Type: GrantFiled: April 25, 2006Date of Patent: March 31, 2009Assignee: University of UtahInventors: Evgueni G. Kholmovski, Dennis Lee Parker, Edward V. R. Dibella
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Patent number: 7501821Abstract: In a method for determination of the transverse relaxation time T2* in MR data, the T2* relaxation is detected in a measurement volume and the transverse relaxation time is determined from the time curve of the magnetization in the measurement volume. In order to be able to more reliably determine the transverse relaxation time T2*, a local magnetic field in the measurement volume is determined and the transverse relaxation time is corrected dependent on the local magnetic field such that a corrected transverse relaxation time is obtained. The local magnetic field is determined by determination of the phase curve of the magnetization from multiple predetermined echo times, the echo times having different intervals (?TE) from one another, and determination of the local magnetic field from the phase curve of the magnetization. The interval between the echo times at least at one point in the measurement volume is adapted such that the local magnetic field can be determined without phase compression.Type: GrantFiled: December 20, 2006Date of Patent: March 10, 2009Assignee: Siemens AktiengesellschaftInventor: Stefan Thesen
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Patent number: 7495439Abstract: A method for magnetic resonance imaging includes performing a preparatory stage of a MR pulse sequence with an MRI system in which a non-selective RF preparatory pulse is used having a bandwidth such that any spin species having corresponding Larmor frequencies within that bandwidth are affected and the bandwidth is centered at a selected frequency which is offset from a nominal Larmor frequency of the desired spin species being imaged. A time period (TI) elapses during which longitudinal spin magnetization recovers; and then an imaging stage is performed in which an RF excitation pulse is generated to produce transverse spin magnetization of the desired spin species, and in which a set of NMR signals are acquired. An image is reconstructed using the acquired set of NMR signals, and the reconstructed image has reduced artifacts due to B0 field inhomogeneities caused by magnetic susceptibility effects.Type: GrantFiled: April 27, 2007Date of Patent: February 24, 2009Assignee: The General Hospital CorporationInventor: Christopher John Wiggins
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Publication number: 20080284470Abstract: A DDS (direct digital synthesizer) remarkably increased in the number of frequencies which can be output while maintaining the phase coherency, and an NMR instrument using such a DDS are provided. A DDS including phase accumulators and a phase-to-amplitude modulator is provided with a plurality of phase accumulators operating with fixed phase implements which are equal to powers of 2, a controller for outputting each bit of a frequency tuning word as control data, a plurality of switches for outputting an output of an associated one of the phase accumulators when an associated one of the control data supplied from the controller is 1 and outputting 0 when the associated one of the control data is 0, and an adder for adding up outputs of the switches.Type: ApplicationFiled: May 14, 2008Publication date: November 20, 2008Inventors: Minseok Park, Michiya Okada, Shuya Hagiwara, Hideki Tanaka
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Patent number: 7429862Abstract: In a PPA MRT method and apparatus, a selected region of k-space containing respective portions of some of the incomplete, measured data lines and respective portions of some of the complete, reconstructed data lines is designated. For each data line in the selected region, a level of the noise therein is identified. For each reconstructed, complete data line in the selected region, a scaling factor is calculated that is dependent on the noise level in that reconstructed, complete data line and the noise level in at least one neighboring incomplete, measured data line in the selected region. The scaling factor is then applied to the reconstructed, complete data line in question, so that the contribution of that line to the overall reconstructed image is adjusted according to the scaling factor. The scaling factor can be limited dependent on where the selected region is located in k-space.Type: GrantFiled: April 18, 2006Date of Patent: September 30, 2008Assignee: Siemens AktiengesellschaftInventors: Evgueni G. Kholmovski, Stephan Kannengiesser
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Patent number: 7425828Abstract: A method of magnetic resonance is provided that uses a frequency swept excitation wherein the acquired signal is a time domain signal is provided. In one embodiment, the method comprises, applying a sweeping frequency excitation and acquiring a time domain signal. The sweeping frequency excitation has a duration and is configured to sequentially excite isochromats having different resonant frequencies. Acquisition of the time domain signal is done during the duration of the sweeping frequency excitation. The time domain signal is based on evolution of the isochromats.Type: GrantFiled: October 11, 2006Date of Patent: September 16, 2008Assignee: Regents of the University of MinnesotaInventors: Michael Garwood, Djaudat S. Idiyatullin, Curt Corum, Steen Moeller
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Patent number: 7423429Abstract: Diagnostic and Therapy apparatus and methods use non-ionizing radiations which are based on integration of nuclear magnetic resonance and radiation manipulation. Quantitative diagnostics integrate the following devices: manual control digital filter/selector (18), frequency matrix monitor (25), frequency image monitor (26), and control panel (28). Therapy integrates the following devices: resonating antenna for radio frequency (4), low radio frequency signal processor/modulator (10), radio frequency pulse amplifier (13) and central pulse control (16). Internal parameters of the emission, such as frequency, power and polarity are selectively manipulated to personalize the therapy and to significantly improve the levels of selectivity and/or differentiation of all the processes.Type: GrantFiled: November 28, 2003Date of Patent: September 9, 2008Inventors: Lázaro Eusebio Hernández Pérez, José Luis Jorge De Moral Más
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Patent number: 7418287Abstract: A method of dynamic magnetic resonance imaging comprising acquiring undersampled magnetic resonance signals for successive temporal time slots. In a space spanned by geometrical space and temporal frequency and on the basic of a priori information the aliased difference magnetic resonance data which are gained by subtracting for respective k-space sampling positions data of a baseline magnetic resonance image from the undersampled magnetic resonance signals are decomposed into difference data which essentially pertain to individual spatial positions at individual time slots.Type: GrantFiled: May 8, 2003Date of Patent: August 26, 2008Assignee: Koninklijke Philips Electronics N.V.Inventors: Jeffrey Tsao, Klaas Paul Pruessmann, Peter Boesiger
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Patent number: 7405564Abstract: A magnetic resonance method is described for forming a dynamic image from a plurality of signals of an object moving relative to at least one RF? receiving antenna. Imaging is acquired by at least two adjacent fields of view (FOV), which are reconstructed to an image over a region of interest which includes both FOVs. Prior to imaging a sensitivity map of the at least one RF receiving antenna at each position relative to the object is determined for each FOV. Thereafter data from the object to be imaged is sampled for each FOV with a reduced number of phase encoding steps with respect to the full set thereof at a fixed position relative to the main magnetic field. The image is then reconstructed from the subsampled signals, which are weighted with the sensitivity factor of the RF receiving antenna at the respective imaging position.Type: GrantFiled: December 10, 2003Date of Patent: July 29, 2008Assignee: Koninklijke Philips Electronics N.V.Inventor: Paul Royston Harvey
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Patent number: 7403007Abstract: In a nuclear magnetic resonance probe, the sample coil is connected to the RF excitation source via transmission lines that are arranged to generate one or more nodal points at the 1H excitation frequency along their lengths and a balanced magnetic filed profile within the sample coil. Heat exchangers are then connected directly to the inner conductor of the transmission line at these nodal points. The transmission line inner conductors are in direct contact with the sample coil and efficiently cool the coil to cryogenic temperatures without interfering with the 1H resonance or RF profile.Type: GrantFiled: February 1, 2007Date of Patent: July 22, 2008Assignee: Broker Bio Spin CorporationInventors: Yit Aun Lim, Eckhard Bez, Xiaozhong Zhang, Werner E. Maas
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Patent number: 7403006Abstract: A method of magnetic resonance is provided that uses a frequency swept excitation wherein the acquired signal is a time domain signal is provided. In one embodiment, the sweeping frequency excitation has a duration and is configured to sequentially excite isochromats having different resonant frequencies. Acquisition of the time domain signal is done during the duration of the sweeping frequency excitation. The time domain signal is based on evolution of the isochromats.Type: GrantFiled: October 11, 2006Date of Patent: July 22, 2008Assignee: Regents of the University of MinnesotaInventors: Michael Garwood, Djaudat S. Idiyatullin
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Publication number: 20080116891Abstract: A system and method for medical imaging includes an improvement to the MP-RAGE pulse sequence that enables the readout bandwidth thereof to be matched to that of other pulse sequences used in the same examination without a significant loss in SNR. More specifically, the present invention includes using a multi-echo MP-RAGE pulse sequence in which multiple gradient-recalled NMR signals are acquired at the desired “matching” bandwidth and combining selected ones of the NMR signals to reconstruct an image. By selecting and combining NMR signals acquired at each phase encoding, the SNR of the resulting reconstructed image can be maintained.Type: ApplicationFiled: November 22, 2006Publication date: May 22, 2008Inventors: Andre van der Kouwe, Bruce Fischl
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Patent number: 7365539Abstract: The present invention presents a new approach to rapidly obtaining precise high-dimensional NMR spectral information, named “GFT NMR spectroscopy”, which is based on the phase sensitive joint sampling of the indirect dimensions spanning a subspace of a conventional NMR experiment. The phase-sensitive joint sampling of several indirect dimensions of a high-dimensional NMR experiment leads to largely reduced minimum measurement times when compared to FT NMR. This allows one to avoid the “sampling limited” data collection regime. Concomitantly, the analysis of the resulting checmical shift multiplets, which are edited by the G-matrix transformation, yields increased precision for the measurement of the chemical shifts. Additionally, methods of conducting specific GFT NMR experiments as well as methods of conducting a combination of GFT NMR experiments for rapidly obtaining precise chemical shift assignment and determining the structure of proteins or other molecules are disclosed.Type: GrantFiled: October 26, 2004Date of Patent: April 29, 2008Assignee: The Research Foundation of State University of New YorkInventors: Thomas A. Szyperski, Seho Kim, Hanudatta S. Atreya
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Publication number: 20080048659Abstract: A method for producing images of a subject containing M spin species using a magnetic resonance imaging (MRI) system includes obtaining N k-space data matrices from N k-space data sets acquired with the MRI system using a pulse sequence with an individual associated echo time. The k-space data matrices each include corresponding data at the same plurality of k-space locations and time stamps are tracked for each k-space location. For each k-space location, a set of linear equations in k-space is solved. The set of linear equations relates corresponding data from the N k-space data matrices, echo times and time stamps to desired calculated k-space data. Calculated data in k-space which is corrected for chemical shift is produced corresponding to each k-space location and aggregated to obtain a k-space calculated data set. The k-space calculated data set is transformed to image space to obtain a corresponding image.Type: ApplicationFiled: February 23, 2007Publication date: February 28, 2008Inventor: Scott Brian Reeder
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Patent number: 7279896Abstract: The methods of the invention for scanning a band of frequencies using a nuclear quadrupole resonance detection system with an array of high temperature superconductor sensors to detect nuclear quadrupole resonance signals improve the nuclear quadrupole resonance detection system performance.Type: GrantFiled: April 29, 2005Date of Patent: October 9, 2007Assignee: E. I. du Pont de Nemours and CompanyInventors: Robby L. Alvarez, James D. McCambridge
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Patent number: 7279897Abstract: The methods of the invention for scanning a band of frequencies using a nuclear quadrupole resonance detection system with an array of high temperature superconductor sensors to detect nuclear quadrupole resonance signals improve the nuclear quadrupole resonance detection system performance.Type: GrantFiled: April 29, 2005Date of Patent: October 9, 2007Assignee: E. I. du Pont de Nemours and CompanyInventors: Robby L. Alvarez, James D. McCambridge