Abstract: 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.

Abstract: In a method and MRI apparatus for the minimization of streak artifacts in modular k-space scanning in magnetic resonance imaging, an odd integer k-space scanning module number N?=2n+1 is defined that defines the number of incrementally rotated repeated modules of the k-space scanning process, a slice selection gradient selects any slice in the range of the object to be examined, and data for all N? angle-oriented k-space scanning modules in the selected slice acquired such that each k-space scanning module has an azmuthal distance of ? ? ? ? 2 = 360 ? ° 2 ? ? N ? from both adjacent projections, with the direction of the scanning of the adjacent k-space scanning modules alternating.

Abstract: A technique is set forth for MR spectroscopy that is capable of reducing signal overlap between metabolite signals for improved clinical analysis of metabolite content. The technique includes varying an echo time across a scanning dimension. Once a span of echo time for an acquisition dimension is determined, and the number of acquisition data points is known, a variance between echo times can be determined. A pulse sequence with differing echo times is then applied for each frame, and after data is acquired, an image is reconstructed that significantly improves metabolite signal separation.

Abstract: Systems and methods for estimating properties of a sample are provided in which, for some embodiments, each datum of a set of data is modeled using a parameterized equation. The parameterized equation has multiple parameters, where each parameter represents a property of the subject. The parameterized equation is inverted, and the inverted parameterized equation provides an indication of one or more properties associated with the subject.

Abstract: The present invention is directed to a system and method of resealing spectroscopic data acquired with phased-array or surface coils to absolute “local” units and, hence, preserves the industry-desirable quantitative approach to single voxel MRS. An MRS signal is acquired from water using a body coil and is used as a reference signal to scale MR spectroscopic data acquired with a plurality of RF receive coils, i.e. phased-array or surface coils. In the resealing process, the amplitude of water in the MRS data will be set to match the amplitude of the water reference signal.

Abstract: In a magnetic resonance tomography apparatus employing a FISP pulse sequence, the pulse sequence is repeated with a repetition time TR with different phase-coding gradient directions and with an alternating operational sign of the flip angle ?. The gradient pulse trains are thereby completely balanced. A phase increment ??=? is generated in addition to the alternating operational sign of the flip angle ? between successive excitation pulses, so that the steady state signals for a first and a second spin ensemble optionally have either identical or reversed signal polarities. A first dataset on the basis of identical signal polarities and a second dataset on the basis of reversed signal polarities are obtained by means of the free selection of the mutual signal polarities. A pure image of the first and the second spin ensembles is thus obtained by the addition and/or subtraction of the first and second datasets.

Abstract: The invention consists of three image-postprocessing phases for the purposes of generating high-quality quantitative MR images (proton density (PD), T1, and T2) as well as high-quality virtual MR images with continuously adjustable computer-synthesized contrast weightings, from source images acquired directly with an MRI scanner. Each of the image-postprocessing phases uses one or several new computer algorithms that improve image quality with respect to prior art, including linear-combination-of source-images (LCSI) algorithms for generating PD images and model-conforming algorithms for generating Q-MR images of tissue properties that influence NMR relaxation.

Abstract: A method of chemical species suppression for MRI imaging of a scanned object region including acquiring K space data at a first TE, acquiring K space data at a second TE, reconstructing images having off resonance effects, estimating off resonance effects at locations throughout the reconstructed image, and determining the first and second chemical species signals at image locations of the scanned object from the acquired signals and correcting for blurring resulting from off resonance effects due to B0 inhomogeneity.

Abstract: An analytical method and apparatus using principal component analysis of nuclear magnetic resonance (NMR) data for rapid molecular structure/function pattern recognition. The presence of a molecular substructure in an organic compound is determined by comparing principal components calculated from chemical shift values of the substructure in selected compounds with those calculated from the chemical shift values of the organic compound. Alternatively, principal components are calculated from the intensities of NMR signals for a full spectrum, or selected regions thereof, to determine whether an organic compound belongs to or is excluded from a set of structurally related compounds. Also, the presence of a pharmacophore in an organic compound can be determined by comparing the principal components derived from data on a set of compounds known to bind to a particular receptor, or have a common biological effect, with the principal components of the data set of the organic compound.

Abstract: The invention provides novel scale-based filtering methods that use local structure size or “object scale” information to arrest smoothing around fine structures and across even low-gradient boundaries. One method teaches a weighted average over a scale-dependent neighborhood; while another employs scale-dependent diffusion conductance to perform filtering. Both methods adaptively modify the degree of filtering at any image location depending on local object scale. This permits a restricted homogeneity parameter to be accurately used for filtering in regions with fine details and in the vicinity of boundaries, while at the same time, a generous filtering parameter is used in the interiors of homogeneous regions.

Abstract: 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.

Abstract: The invention consists of three image-postprocessing phases for the purposes of generating high-quality quantitative MR images (proton density (PD), T1, and T2) as well as high-quality virtual MR images with continuously adjustable computer-synthesized contrast weightings, from source images acquired directly with an MRI scanner. Each of the image-postprocessing phases uses one or several new computer algorithms that improve image quality with respect to prior art, including linear-combination-of source-images (LCSI) algorithms for generating PD images and model-conforming algorithms for generating Q-MR images of tissue properties that influence NMR relaxation.

Abstract: In a method for the operation of a magnetic resonance apparatus having a gradient system and a radio-frequency system that, among other things, are utilized for location coding of magnetic resonance signals, magnetic resonance signals from at least parts of a region of an examination subject to be imaged are acquired in a time sequence, and a deformation of the region to be imaged occurring during the time sequence is identified and the location coding is adapted according to the identified deformation.

Abstract: A Nuclear Magnetic Resonance (NMR) probe device (20) is disclosed. NMR probe device (20) includes a plurality of detection coils (30, 40) each operable to detect a signal from a corresponding one of a plurality of samples (34, 44) undergoing NMR analysis. Also included is a plurality of tuning circuits (31, 41, 38, 48) each coupled to one of detection coils (30, 40) to tune the one of the detection coils (30, 40) to a corresponding resonant frequency for the NMR analysis of the corresponding one of the samples. An electromagnetic shield (22) is positioned between a first one of the detection coils (30, 40) and a second one of the detection coils (30, 40) to isolate the first one of the detection coils (30, 40) and the second one of the detection coils (30, 40) from each other.

Abstract: A magnetic resonance method is described for forming a fast dynamic image with an automatically generated grid of essentially orthogonally arranged grid lines by a saturation information induced over the object to be imaged. Therefore a first set of parallel saturation planes is obtained by applying a first nonselective RF pulse with a flip angle of 90°, an intermediate magnetic field gradient pulse in direction of the spatial modulation, and a second nonselective RF pulse with a flip angle of 90°. A subsequent spoiler gradient pulse is applied in the direction of the magnetic field gradient for slice selection. Subsequently a second set of parallel saturation planes is obtained in the same manner by inverting one second RF pulse with respect to the first RF pulse. Further the first and the sets of saturation planes are subtracted from each other to obtain a grid free of any contribution of relaxation components of magnetization.

Abstract: In a method for operating a magnetic resonance device, a magnetic resonance signal is recorded over a span of time, and in order to produce a magnetic resonance spectrum, the magnetic resonance signal in the time domain is subjected to a Fourier transformation. The magnetic resonance signal is weighted with a bell-shaped window function before the Fourier transformation, thereby preventing broadening of resonance lines in the displayed frequency spectrum, so that non-dominant resonance lines, such as those associated with the metabolites, can be more readily analyzed.

Abstract: The invention features methods of selecting chemical peaks from two-dimensional magnetic resonance spectra for one-dimensional extraction and quantification methods using these one-dimensional extractions. The methods permit enhanced differentiation of particular peaks in two-dimensional magnetic resonance spectroscopy and allow for quantification of chemical concentrations in test samples, such as human brain tissue, having complex magnetic resonance spectra due to the presence of numerous chemicals. These new techniques can be used to provide information about the concentrations of a variety of chemicals, including metabolites, in both biological and non-biological media.

Abstract: A method of screening a subject for the presence of lipoprotein X includes the steps of: producing a measured lipid signal lineshape of an NMR spectrum of a blood plasma or serum sample obtained from a subject; generating a calculated lineshape for the sample, the calculated lineshape being based on derived concentrations of lipoprotein components potentially present in the sample, the derived concentration of each of the lipoprotein components being the function of a reference spectrum for that component and a calculated reference coefficient, wherein one of the lipoprotein components for which a concentration is calculated is lipoprotein X; and determining the degree of correlation between the calculated lineshape of the sample and the measured lineshape spectrum of the sample.

Abstract: An object of the present invention is to produce images devoid of band artifacts. Data acquisition in SSFP is repeated N times (where N denotes the power of 2) in order to acquire data fv(k), which ranges from data fv(0) to data fv(N−1), from views v constituting a k-space. At this time, the phase of an RF pulse is varied based on an expression of 360°·v·k/N. If an operator designates Fourier transform imaging, a Fourier transform is performed on data fv(k) relative to each of the phases indicated by the RF pulse in order to produce data Fv(n). If the operator does not designate Fourier transform imaging, the data fv(k) is regarded as the data Fv(n) as it is. Any of at least either of weighted addition and MIP processing and root-mean-square conversion selected by the operator is then performed on the data Fv(n) in order to produce data Av. An image is reconstructed based on the data Av.

Abstract: A system and method are disclosed that use the steady-state free precessing (SSFP) technique for MR imaging to allow the acquisition of MR angiography images in which the acquisition is not time dependent upon the first passage of a contrast agent. The technique includes applying a pulse sequence with refocusing S− signals from a train of RF pulses to a desired field-of-view (FOV) in a patient in which a contrast bolus has been injected. An SSFP image of the desired FOV is acquired, together with an S− SSFP mask image of the desired FOV. The S− SSFP mask image is subtracted from the SSFP image in order to reconstruct an image with improved visualization of the arterial and venous structures and reduce mis-registration artifacts.

Abstract: An apparatus for obtaining multiple spectra from a plurality of samples through the use of nuclear magnetic resonance (NMR) spectroscopy. A plurality of microcoils are coupled to and are in operable communication with an NMR spectrometer. The coils are operable in both a transmit mode and a receive mode to transmit RF energy to a sample being analyzed and to receive the return data for analysis by the NMR spectrometer. At least one switch is coupled to the plurality of coils and the NMR spectrometer. A controller for the NMR spectrometer is coupled to the switch and is used to control alternative activation of the coils for NMR data acquisition of multiple samples.

Abstract: A magnetic resonance signal is acquired from a JHH-coupled 1H within an object. After application of a wideband first radio-frequency magnetic pulse, a first frequency-selective radiation pulse is applied to a specific nucleus 1H coupled to a desired nucleus 1H through a homonuclear spin-spin coupling (JHH-coupling), thus multiple-quantum coherences between the nuclei 1H being generated. A second radio-frequency magnetic pulse is then applied. A second frequency-selective radiation pulse is then applied to the specific nucleus 1H to generate a single-quantum coherence of the desired nucleus 1H. Thus, a magnetic resonance signal can be acquired from the desired nucleus 1H. The acquisition of the signal is robust, adjustment in the phases of the radio-frequency magnetic pulses is not required, and an acquired spectrum is avoided from being visually complicated.

Abstract: NMR spectroscopy data recovery methods and apparatus for improving the quality of an NMR spectrum are disclosed. The NMR spectrum is improved by acquiring more than the half spin-echo data signal and using an iterative numerical method to reconstruct the missing data points of the corresponding full symmetrical spin-echo data signal. The method includes filtering the initial data signal to extract a low-resolution phase term. The low-resolution phase term is used to form a phase-constrained initial data signal, which is Fourier-transformed to obtain a reconstructed data signal. The reconstructed data signal is modified to include the original spin-echo signal data. The formation of the reconstructed spin-echo data signal and subsequent modification is iterated until convergence is obtained. The reconstructed data signal is then Fourier-transformed to form a reconstructed NMR spectrum.

Abstract: An asymmetric spin-echo (ASE) sequence having a variable asymmetry (&Dgr;TE) with respect to the RF pulse is used for imaging paramagnetic, diamagnetic or ferromagnetic instruments within tissues during interventional MRI procedures. The degree of asymmetry introduced determines an apparent size of the imaged instrument. In one embodiment of the invention, the amount of asymmetry is varied as a function of the phase encoding gradient steps. In this manner, the sequence is made sensitive to local gradients in the magnetic field but left insensitive to large scale variations such as those introduced by main magnetic field inhomogeneities.

Abstract: A magnetic stereotaxis system (MSS) is functionally integrated with a magnetic resonance imaging (MRI) system to provide a non-invasive, radiation-free modality for integrated MRI/MMS tracking and guiding of an interventional medical device. Shielding is provided between regions where the patient is moved so that magnetic fields from one procedure do not interfere with the function or materials used in the other procedure. A process is described where a patient is moved on a track from one procedural field to another procedural field with the shield available between different zones provides for the procedures. A computer is associated with the system to supervise performance of a variety of functions and procedures within the surgical environment.

Abstract: An MRI system is employed to acquire image data using a pulse sequence in which k-space is sampled in a Fibonacci spiral trajectory. A single pulse sequence may be used to sample all of k-space with a single spiral arm, or k-space can be sampled with a plurality of interleaved Fibonacci spiral arms by performing a corresponding series of pulse sequences.

Abstract: A technique is described for correcting phase errors in a bipolar readout gradient MRI imaging sequence, such as an EPI examination. The technique employs alternating sets of oscillating readout gradient pulses. Each readout pulse train has a polarity which is inverted with respect to an immediately preceding and an immediately succeeding readout sequence. The collected data then incorporates both image data and data which is used to correct for phase errors. Following data acquisition, correction factors may be determined from the k-space frames for correction of successive k-space data. K-space frames may be reformatted to inherently correct for phase errors, followed by combination of hybrid k-space data frames to obtain a corrected image.

Abstract: The present invention provides a magnetic resonance force microscopy apparatus and method for use in combination with an oscillator. The oscillator has a motional body and one member of a sample/magnet pair is disposed on the motional body. The present invention actuates the motional body. The apparatus comprises a holder adapted to mount the second member of a sample/magnet pair, an RF field generator positioned to apply a field to the sample, a motion sensor adapted to be coupled with the motional body, an actuator adapted to be coupled with the motional body, and a motion controller coupled with the actuator and with the motion sensor.

Abstract: Disclosed is improved quantitative in vivo spectroscopy by means of F1-oversampled J-Resolved 2D spectroscopy. Reconstruction makes full use of internal signals for 2D water lineshape, T.sub.2 and partial volume correction, and analysis uses 2D complex model spectra fitting. The preferred embodiment of the new method integrates these features into PRESS localized brain spectroscopy and is carried out without the need for water suppression.

Abstract: A magnetic resonance imaging ("MRI") simulator for evaluating an MRI device comprises sections for being selectively coupled to the corresponding portions of the MRI device. Data representative of a previously imaged object is provided to the portions of the MRI device, for processing. The results of the processing are evaluated to determine whether portions of the MRI device are operating properly. Methods of evaluating an MRI device and an MRI device incorporating such a simulator are also disclosed.

Abstract: In a method for identifying spikes in magnetic resonance signals obtained in magnetic resonance tomography, a magnetic resonance signal is obtained and is high-pass filtered. A statistical evaluation of the high-pass filtered magnetic resonance signal is then undertaken to determine whether the high-pass filtered magnetic resonance signal contains spikes which can be differentiated from a noise signal. If so, such spikes are identified, and can be removed from the raw data so that they do not contribute to image artifacts.

Abstract: A method of simultaneous multinuclear magnetic resonance imaging and spatially localized NMR spectroscopy is disclosed. Clinical implementation of the disclosed method allows routine in vivo NMR spectroscopy studies without significantly increasing the time of conventional MR imaging studies. A unique sequence of rf excitation and magnetic gradient pulses is used which allows chemical shift imaging data to be acquired simultaneously with conventional imaging data. A deconvolution method extracts the chemical shift information for analysis and display.

Abstract: NMR imaging is effected by application of two normal diagonal planes to develop line volumes at major intersections which are converted into a slice image. Rapid line scan imaging is achieved by successive diagonal excitation of previously unexcited regions. Spoiler magnetic gradient fields and applied periodically to dephase and in turn eliminate minor or spurious echoes from other intersections of the two normal diagonal planes.

Abstract: The method and device for NMR Fourier zeugmatography utilizes amplitude-modulated r.f. pulses (90.degree. and 180.degree. pulses) for the excitation of nuclear spins and the generating of nuclear spin echo signals. For three-dimensional Fourier zeugmatography, r.f. pulse having a large bandwidth (for example 10-50 kHz) are desired. The use of amplitude-modulated signals then implies an undesirably high peak power of the r.f. generator. In accordance with the invention, use is made of a frequency-modulated signal which can have a substantially constant amplitude and which preferably covers the desired frequency spectrum at a uniform speed.

Abstract: Zero-quantum nuclear magnetic resonance imaging and spectroscopy in an inhomogeneous or low homogeneity magnetic field are disclosed. Specific pulse sequences have been developed which produce zero-quantum coherence resolved images and spectra. Unlike conventional NMR resolved images and spectra the zero-quantum coherence resolved images and spectra are unaffected by magnetic field inhomogeneity, thereby allowing the images and spectra of substances to be obtained where magnetic field inhomogeneity would previously have made it impossible.

Abstract: Off-center field-of-view studies are achieved in MR multi-slice imaging methods by rotation of the axes along which the phase-encoding and readout magnetic field gradients are applied and offsetting the frequency of the MR receiver from the system isocenter frequency. The method is particularly useful in two-dimensional multi-slice imaging using surface coils.

Abstract: In the NMR apparatus the resonant conditions may be kept constant by adjusting the strength of the static magnetic field. The echo signal that is induced under the specific conditions is processed so as to obtain the deviation of the resonant frequency in the correction circuit. The shift of the given static magnetic field is calculated based upon the deviation of the resonant frequency. The DC energizing current for the H.sub.O power supply is varied based upon the magnetic field shift so as to maintain the NMR phenomenon at the desirable resonant conditions.

Abstract: The present invention relates to an improved nuclear magnetic resonance spectroscopy for selectively detecting multiple quantum transitions of a selected order, the transitions taking place in a sample containing a system of rotating magnetic resonators. The spectrometry comprises the steps of: (a) applying a pulse train to the resonators, the pulse train consisting of RF pulses in which at least one pulse is .phi. degrees out of phase with the last pulse; (b) detecting the free induction decay signal emanating from the resonators for a period of time t2 after the application of the pulse train, using two channels of detecting system which are 90.degree. out of phase with each other, and storing it in a memory. The steps are repeated changing the values of the evolution time t1, resetting the values of .phi., and adding 90.degree., 180.degree., and 270.degree. to all values of .phi.. The data are combined and converted to frequency domain by double Fourier transformation with respect to t1 and t2.

Abstract: A method for providing NMR images free of chemical shift artifacts, obtained from selected nuclei of a sample containing nuclei having chemically-shifted NMR frequencies is described. Non-selected nuclei of the sample are selectively saturated prior to applying an NMR imaging sequence by applying to the sample an RF pulse containing frequencies equal to the chemically-shifted frequencies of the non-selected nuclei and having a narrow frequency spectrum about the chemically-shifted frequencies. Alternatively, selected nuclei are directly excited during application of an NMR imaging sequence by applying to the sample an RF pulse containing frequencies equal to the chemically-shifted frequencies of the selected nuclei, and having a narrow frequency spectrum about the chemically-shifted frequencies so as to exclude signal contributions from the non-selected nuclei. These selective pulses are applied in the absence of the imaging magnetic field gradients.

Abstract: This method and apparatus are directed to baggage inspection, and more particularly, baggage inspection to locate explosives. In the preferred and illustrated embodiment, a conveyor system is utilized to transport a bag past a first magnet to achieve an initial nuclear magnetic resonance (NMR) polarization of a selected element. The element in the preferred embodiment is hydrogen, it being noted that hydrogen in explosives has a long T.sub.1 and a short T.sub.2. The first magnet provides an initial polarization. The bag continues on the conveyor belt past a second magnet. The second magnet provides the measurement field intensity and a coil contains an interacting RF forming the interrogation pulses. Echos are received. In the preferred embodiment, first and subsequent second echos are received and stored. The two signals are subtracted from one another to a null. The NMR response of elemental hydrogen in compounds typified by explosives (having a long T.sub.1 and short T.sub.

Abstract: To produce image information from an object it is subjected to a continuous static magnetic field along a Z axis and to sets of sequences of gradient G.sub.x, G.sub.y and G.sub.z to the magnetic field. Spins in a selected plane (the X-Z plane) are excited by selective rf pulses and an associated G.sub.y gradient and the selected spins are subjected to a reversed G.sub.y gradient together with a G.sub.x gradient. The G.sub.y gradient is then switched off and the direction of the G.sub.x gradient is then repeatedly reversed. During the action of reversal of the G.sub.x gradient a small G.sub.z gradient is provided. Each reversed G.sub.x gradient is held constant for a sufficient time for a free induction decay signal to be generated thus providing a multiple echo of the spins in the selected plane. Alternate signals are time-reversed and then both the time-reversed and non time-reversed signals are subject to Fourier transformation.

Abstract: The invention provides an investigation of chemical shift for an element, for example phosphorus, in a region of a body, in one example resonance is preferentially in a line in a slice of the body. Frequency dispersion down the line is produced by a pulsed field having a switched gradient so that the frequency distribution is in steps. This allows a chemical dispersion in each limited region of the line without overlap with adjacent regions. The measured FID signals are Fourier transformed to give a spatial and chemical analysis of the line.Alternatively resonance is excited in a slice and lines selected by a pulsed gradient which gives chemical dispersion as well as spatial dispersion between the lines after Fourier Transformation. This is repeated for many different directions of the pulsed gradient to allow analysis of a chemical line by convolution techniques to give a picture for the slice.

Abstract: In a heteronuclear system, the indirect detection of nuclei S, of weak gyromagnetic ratio, coupled to nuclei I, of strong gyromagnetic ratio, is accomplished by generation of zero and double quantum coherence between the I and S spin systems, during a preparatory period, t.sub.p. The zero and double quantum transitions are then interchanged at the midpoint of the evolution period, t.sub.1, producing an echo modulated only by S and I-I interactions at the end of the period t.sub.1, at which time the zero and double quantum coherence is then converted to I spin single quantum coherence yielding a free induction decay wave form S(t.sub.2) for given t.sub.1. The period, t.sub.1, is then varied to obtain a two-dimensional function S(t.sub.1, t.sub.2) which is then fully transformed to the frequency domain obtaining S(.omega..sub.1, .omega..sub.2) whereby the chemical shift of the coupled S spin is obtained along the .omega..sub.1 axis and the chemical shift of the I spin is obtained along the .omega..sub.2 axis.

Abstract: A method and means of generating an electron spin echo signal having a relatively higher output frequency than the input frequency of the applied 90.degree. and 180.degree. RF pulses applied to an electron spin echo sample located in a static magnetic field by increasing the magnitude of the Zeeman magnetic field by a predetermined amount after the application of the 90.degree. and 180.degree. pulses. Also the spin echo sample is situated in a microwave cavity which has two resonant frequency modes, the first of which has a relatively high Q while the second has a relatively low Q. The 90.degree. and 180.degree. RF pulses are applied to the system at the first resonant frequency having the high Q while the spin echo signal is coupled out of the system at the second resonant frequency having the low Q.