Abstract: A method and apparatus for determining abnormal pressure zones of a geologic formation using NMR measurements, preferably for logging-while-drilling applications. In a preferred embodiment, a normal compaction trend is constructed using NMR-derived clay bound water volume (CBW) content for non-consolidated subsurface formations or bulk volume irreducible (BVI) and CBW for consolidated formations versus depth. Deviations from this normal compaction trend are used to indicate the presence of shale sections with higher porosity that directly corresponds to an overpressured top seal or transitional zone.

Abstract: An improvement in a magnetic resonance method for determining at least one property of multiple samples, including introducing multiple samples into the interrogation zone simultaneously; applying a gradient magnetic field to the interrogation zone wherein different positions within the interrogation zone are sensitive to different specific frequencies; monitoring energy emitted by the samples in the different positions and generating an output signal having a characteristic which is proportional to the energy emitted corresponding thereto in different frequency bands; and, attributing the signals to specific positions and samples, and comparing the output signal characteristics of the specific positions and samples with like data obtained from at least one similar sample to provide an indication of the corresponding property of the samples.

Abstract: The present invention provides a method for obtaining a multi-dimensional proton density distribution from a system of nuclear spins. A plurality of nuclear magnetic resonance (NMR) data is acquired from a fluid containing porous medium having a system of nuclear spins. A multi-dimensional inversion is performed on the plurality of nuclear magnetic resonance data using an inversion algorithm to solve a mathematical problem employing a single composite kernel to arrive at a multi-dimensional proton density distribution. Ideally, the mathematical problem can be cast in the form of a Fredholm integral of the first kind wherein a two or more kernels can be reduced to a single composite kernel for ease of solution. Preferably, a series of conventional CPMG pulse sequences, using a conventional NMR tool, can be used to excite the system of nuclear spins.

Abstract: This invention is a method to measure fluid flow properties of a porous medium, including, but not limited to, the fluid flow permeability. In a preferred embodiment, the measurements are made down hole in drill wells exploring for hydrocarbons or acquifers. The measurement involves two types of instruments. One instrument creates a pressure wave in the porous medium, which generates motion of the fluid in the pore space. The second instrument measures the fluid motion in the pore space using Nuclear Magnetic Resonance (NMR) methods. Any type of instrument that can generate a pressure gradient is suitable, including instruments that are remote from the NMR instrument. Magnetic field gradients can be used to localize the NMR signal to a specific region within the porous medium. The magnetic field gradient also provides the method by which the fluid motion is encoded on to the NMR signal.

Abstract: A signal processor, for use with a zero crossing module of a vortex flow meter, includes a peak amplitude detector, a comparator, and a filter module. The filter module is enabled when the comparator determines that the amplitude is less than a low flow rate threshold. The filter module filters a vortex signal and the filtered signal is provided to a frequency estimator that uses a zero crossing algorithm. The signal processor may increase the signal-to-noise ratio at low flow rates for which the frequency estimator may not otherwise be able to accurately estimate the flow rate. Low flow rates may be measured by determining that there is a low flow rate using amplitude detection of a vortex signal, filtering the vortex signal based on the amplitude detection, and using a zero crossing algorithm on the filtered vortex signal.

Abstract: The present invention provides a system and method of removing heat from an MR imaging device while maintaining internal and external temperatures below maximum operating limits, thereby enabling higher power applications for faster imaging with improved image quality as well as, allowing longer scan times for interventional procedures. The system includes a vacuum chamber housing the gradient coils and a vacuum pump connected thereto to regulate the pressure and humidity within the chamber. A heat exchanger, coolant pump, and controller are provided to regulate the temperature of coolant designed to dissipate heat from the gradient coils in response to at least one temperature sensor.

Abstract: A non-selective saturation pulse together with a series of notched RF saturation pulses are used to acquire MR perfusion data. The non-selective saturation recovery RF pulse is non-selective and is designed to be effective at blood pool suppression for a first slice as well as a next slice in a series of slice locations. The first slice. location may be placed at an angle or plane that is not necessarily coaxial with the other slice locations to be imaged. The present invention supports the acquisition of MR data with efficient spatial coverage and a calibration slice of data that provides a linear measure of signal intensity versus contrast concentration in a blood pool.

Abstract: The invention is a method of reducing the effects of non-formation signals in an NMR logging echo signal obtained within a borehole in an earth formation. The method obtains a non-formation signal by the application of at least an excitation pulse, and preferably also at least one refocusing pulse. The obtained signal is used to numerically construct a synthetic ringing signal sequence. The constructed signal can then be subtracted from an NMR echo signal to reduce the effects of ringing.

Abstract: A system and method are disclosed using continuous table motion while acquiring data to reconstruct MR images across a large FOV without significant slab-boundary artifacts that reduces acquisition time. At each table position, full z-encoding data are acquired for a subset of the transverse k-space data. The table is moved through a number of positions over the desired FOV and MR data are acquired over the plurality of table positions. Since full z-data are acquired for each slab, the data can be Fourier transformed in z, interpolated, sorted, and aligned to match anatomic z locations. The fully sampled and aligned data is then Fourier transformed in remaining dimension(s) to reconstruct the final image that is free of slab-boundary artifacts.

Abstract: Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned de superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

Abstract: A method for determining properties of a mixture of fluids includes: (a) acquiring a plurality of nuclear magnetic resonance measurements from the mixture of fluids, each of the plurality of nuclear magnetic resonance measurements having a different value in an acquisition parameter for which at least one relaxation selected from the group consisting of longitudinal relaxation and transverse relaxation affects magnitudes of the nuclear magnetic resonance measurements; (b) generating a model of the mixture of fluids; (c) calculating a synthesized nuclear magnetic data set based on the model; (d) comparing the synthesized nuclear magnetic data set with the nuclear magnetic resonance measurements; and (e) adjusting the model and repeating (c) and (d), if difference between the synthesized nuclear magnetic data set and the nuclear magnetic measurements is greater than a minimum.

Abstract: The present invention relates to a method and apparatus for measuring a property relating to fluid flow in an earth formation, more specifically to directly measuring formation permeability and other fluid characteristics. The present invention provides a method for determining the permeability of a hydrocarbon bearing earth formation, which method comprises the steps of: locating a tool at a selected position in a borehole penetrating the earth formation; inducing a flow of fluid within the earth formation to said tool; creating at least two MRI images of said fluid while flowing within the earth formation to said tool, said at least two images being created at different times; determining displacement of said fluid within the earth formation between said different times, using the at least two MRI images.

Abstract: In a magnetic resonance tomography apparatus and a method for the operation thereof, two neighboring slices of an examination subject are simultaneously excited and the measurement time thus can be shortened without SNR loss. The radiofrequency excitation pulse encodes the first slice with a phase offset of +90° or ?90° compared to the second slice, so that a response signal contains magnetization information about both slices, [this information] being separated on the basis of the phase offset.

Abstract: In one embodiment of the present invention, a method of measuring the molecular displacement of a fluid is disclosed comprising: (a) applying a strong magnetic field gradient to the fluid; (b) applying a sequence of oscillating magnetic field pulses to the fluid wherein the sequence includes a first portion followed by a second portion, wherein the first portion spatially modulates the magnetization state of the fluid and the second portion monitors the evolution of the modulation; (c) detecting magnetic resonance signals from the fluid; and (d) analyzing the detected signals to determine the molecular displacement of the fluid. This method may be used to determine the diffusion of the fluid or the restricted diffusion of the fluid through the porous media if the fluid is within a porous media (such as earth formation, bone, wood or other material). Also disclosed is a logging tool configured to implement this methodology.

Abstract: A method for compensation for object motion during a scan, especially an magnetic resonance imaging (MRI) scan is provided. The method involves taking a first data set corresponding to a first focussed image and adding a number of data points to form a slightly higher resolution image. Possible motions can then be modelled on the added data points and the effect on the focussing of the slightly higher resolution image determined using appropriate focus criteria.

Abstract: For the purpose of enabling parallel imaging even when a navigator echo is used to phase-correct an imaging echo, the present invention involves: exciting spins within a subject to acquire an imaging echo generated by the excited spins along with a navigator echo, with a reduced field-of-view via a plurality of receiver systems; conducting phase correction on the imaging echo based on the navigator echo; producing an intermediate image based on the phase-corrected imaging echo from each of the plurality of receive systems; generating a sensitivity matrix for the plurality of receiver systems; correcting the phase of matrix data in the sensitivity matrix; and producing an image with a full field-of-view based on the intermediate image and the phase-corrected sensitivity matrix.

Abstract: The present invention discloses a method and apparatus to make a nuclear magnetic resonance measurement on a flowing fluid using varied wait times. In one method, NMR measurements are made by: a) flowing the fluid through a static magnetic field; b) applying a group of oscillating magnetic field pulses to the flowing fluid, wherein the group of pulses is comprised of an initial pulse and one or more refocusing pulses; c) detecting magnetic resonance signals from the flowing fluid; d) after a wait time, repeating (b) and (c) one or more times, wherein at least two of the repetitions have varied wait times; and e) analyzing the detected magnetic resonance signals to extract information about the flowing fluid. Further, varied wait time measurements may be useful in determining the flow rate of the sample.

Abstract: Provided are pulse imaging sequences and methods for 2D multi-slice T1&rgr;-weighted and 3D T1&rgr;-weighted magnetic resonance imaging (MRI). Further provided is a self-compensating spin-locking sequence for correcting and reducing artifacts in T1&rgr;-weighted imaging. Also provided is a sequence combining 3D T1&rgr;-weighted MRI with a self-compensating spin-locking pulse for facilitating T1&rgr;-weighted imaging with surface coils.

Abstract: A method for obtaining nuclear magnetic resonance measurements includes inducing a static magnetic field in a formation fluid sample; applying an oscillating magnetic field to the fluid sample according to a preparation pulse sequence that comprises a J-edit pulse sequence for developing J modulation; and acquiring the nuclear magnetic resonance measurements using a detection sequence, wherein the detection sequence comprises at least one 180-degree pulse. The method may further include acquiring the nuclear magnetic resonance measurements a plurality of times each with a different value in a variable delay in the J-edit pulse sequence; and analyzing amplitudes of the plurality of nuclear magnetic resonance measurements as a function of the variable delay to provide J coupling information.

Abstract: The present invention provides an improved NMR sequence for detecting small amount of a substance having short NM transversal relaxation in the presence of a large amount of a substance having long NMR relaxation. A sequence of pulses enables the original z-oriented magnetization vector of a substance to experience differing reorientation effects based on the relative transverse relaxation rate of the substance. After said pulse sequence, a substance with long transverse relaxation experiences a substantial inversion of its nuclear magnetization vector, while a substance with short transverse relaxation experiences a nearly zero value of its vector. After a determinable wait time, said vectors can be shown to experience recognizably different behavior under the application of a CPMG sequence of pulses. Appropriate wait time can be determined by zeroing out spin echoes during the CPMG pulse sequence.

Abstract: An NMR system comprises an NMR probe comprising multiple NMR detection sites. Each of the multiple NMR detection sites comprises a sample holding void and an associated NMR microcoil. The NMR system further comprises a controllable fluid router operative to direct fluid sample to the multiple NMR detection sites.

Abstract: One aspect of the invention provides a magnetic resonance diagnosis apparatus capable of performing magnetic tagging of a three-dimensional region to visualize three-dimensional motion or to quantitatively handle the motion. In this apparatus, a control unit controls a gradient magnetic field power source of each axis so that magnetization by gradient magnetic fields generated from a gradient magnetic field coil describes a three-dimensional orbit inside a k-space and performs magnetic tagging for a predetermined three-dimensional region of an object by adjusting a magnitude of gradient magnetic field pulses, pulse intervals and application time. Consequently, one aspect of the invention can provide an MRI apparatus capable of more flexibly observing motion of organs and flow of blood.

Abstract: In a magnetic resonance imaging method and apparatus and computer program product, spatial scanning of a block-shaped volume of a patient is undertaken by applying a phase-coding gradient in a slice selection direction, as well as by applying a frequency-coding gradient in a plane vertical to the direction of the phase-coding gradient. The body is uniformly and continuously moved by uniformly and continuously moving a table on which the body is situated until the block-shaped volume moves uniformly through the homogeneity volume of the magnetic resonance apparatus. The gradient fields are simultaneously uniformly continuously shifted in conformity with the motion of the table, so that the block-shaped volume being scanned does not move in relation to the table, and thus does not move in relation to the patient, until the block-shaped volume proceeds through the entirety of the homogeneity volume, and scanning is completed.

Abstract: A dose of a contrast agent (44) is administered to the patient (42). A magnetic resonance is excited by an RF pulse (200) in a region of interest of the patient (42). An echo-planar imaging (EPI) readout waveform is implemented a preselected duration after the excitation to generate T2 or T2* weighted data. During the preselected duration, another echo planar readout waveform is implemented to generate T1 or proton density weighted data. The data is reconstructed (56) to generate a T2 or T2* weighted image and a T1 weighted image. The T1 and T2 or T2* weighted images are combined (62) to generate a contrast enhanced image.

Abstract: An ECG-prep scan is used to set an optimum time phase in both systole and diastole of the heart. At each of the different time phases, an imaging scan is started to acquire a plurality of sets of echo data. An artery/vein visually separated blood flow image is produced from the echo data. The imaging scan uses a half-Fourier technique, for example. This provides high-quality blood flow images with shorter scan time, without injecting a contrast medium. Additionally, with a readout gradient pulse applied substantially parallel with a direction of slowly flowing blood, a scan is performed in synchronism with an optimally determined cardiac time phase. The readout gradient pulse has a dephasing pulse for enhancing differences in a flow void effect depending on blood flow velocities. This enables slow-speed flows, such as blood flows in the inferior limb, to be depicted without fail.

Abstract: The present invention provides a method for obtaining a multi-dimensional proton density distribution from a system of nuclear spins. A plurality of nuclear magnetic resonance (NMR) data is acquired from a fluid containing porous medium having a system of nuclear spins. A multi-dimensional inversion is performed on the plurality of nuclear magnetic resonance data using an inversion algorithm to solve a mathematical problem employing a single composite kernel to arrive at a multi-dimensional proton density distribution. Ideally, the mathematical problem can be cast in the form of a Fredholm integral of the first kind wherein a two or more kernels can be reduced to a single composite kernel for ease of solution. Preferably, a series of conventional CPMG pulse sequences, using a conventional NMR tool, can be used to excite the system of nuclear spins.

Abstract: A system and method are disclosed using continuous table motion while acquiring data to reconstruct MR images across a large FOV without significant slab-boundary artifacts that reduces acquisition time. At each table position, full z-encoding data are acquired for a subset of the transverse k-space data. The table is moved through a number of positions over the desired FOV and MR data are acquired over the plurality of table positions. Since full z-data are acquired for each slab, the data can be Fourier transformed in z, interpolated, sorted, and aligned to match anatomic z locations. The fully sampled and aligned data is then Fourier transformed in remaining dimension(s) to reconstruct the final image that is free of slab-boundary artifacts.

Abstract: A method and system for detecting an anomaly in a fluid system, comprising exposing a sample of the fluid system to a first, non-oscillating magnetic field, simultaneously exposing the sample to a second, oscillating magnetic field orthogonal to the first field, modulating one or both of the magnetic fields, and detecting and capturing a resulting NMR signal from the sample. An analysis of the captured signal, typically involving transformation of the signal into an NMR frequency domain spectrum, can be performed to look for specific changes in the signal indicative of the presence of a particular anomaly.

Abstract: A method and apparatus for determining the oil and water content of a heavy oil and water emulsion includes a low field NMR spectrometer and means for determining the total amplitude of an NMR spectrum at specified T2 values.

Abstract: A multi-slice double inversion recovery (DIR) pulse sequence with read out of a signal for imaging successive slices implemented on a magnetic resonance image scanner. In the method, when the DIR pulse sequence is applied before imaging each slice, a slab-selective inversion re-inverts the entire slab that includes all of the slices. All slices are imaged within a predefined repetition time (TR). The number, N, of slices acquired per TR controls the inversion time to execute the read out of the signal for imaging each slice at a zero-crossing point of blood. In a test, multi-slice DIR images of carotid arteries were obtained with N ranging from 2-8, for four subjects. The results were compared with those for both standard single-slice DIR, and inflow saturation techniques. Multi-slice DIR with N=2-6 provided blood flow suppression in carotid arteries similar to that of single-slice DIR, and significantly better than inflow saturation.

Abstract: In a method for automatic determination of the actual speed interval of a flowing medium in flow measurements in magnetic resonance imaging, an overview image (localizer) is acquired displayed on a screen, a scout flow measurement is performed by acquiring an image series during a motion cycle at a pre-determined speed interval in a tissue-area to be measured, the peak speed of the medium in the tissue area to be measured is determined on the basis of the scout flow measurement, an optimized flow measurement is performed by acquiring the same images from the acquired image series on the basis of the determined peak speed, and the speed-resolved tissue area obtained by means of the optimized flow measurement is displayed on the screen.

Abstract: Without injecting a contrast medium, blood pumped out from the heart can preferably be depicted in a non-invasive fashion, resulting in a greatly shortened scanning time for data acquisition. An MRI system temporal phase detector acquires an ECG signal of an object, and an imaging scanner performs a three-dimensional scanning pulse sequence every slice encoding in synchronism with an ECG signal. The pulse sequence includes an RF excitation pulse for which a repetition time is set to be shorter than conventional. In addition, the pulse sequence includes a slice-directional gradient for performing data acquisition based on the slice encoding in an approximately parallel direction to a running direction of blood flow. Furthermore, the pulse sequence includes a phase-encoding directional gradient for applying phase encoding in a direction approximately coinciding with a running direction of the blood flow.

Abstract: To optimize in advance a desired image quality determining pulse sequence parameter incorporated in an imaging scan, a preparation scan is adopted. The preparation scan is performed with the amount of at least one desired image quality parameter changed for each of plural preparatory images, so that a plurality of preparatory images at the desired same region of the object are acquired. For example, one such image quality parameter is TI (inversion time). The acquired preparatory scan data are processed into a plurality of preparatory images for display. A desired preparatory image is then selected from the plural preparatory images displayed, and the amount of the desired parameter used for that selected preparatory image is then set for use in the pulse sequence for a complete diagnostic imaging scan. Hence the desired image quality determining parameter of the pulse sequence is caused to have an optimum value before an actual complete diagnostic imaging scan.

Abstract: An MRI apparatus obtains an ASL (Arterial Spin Labeling) image of a region to be imaged in a subject by performing a scan to the region to be imaged independently in a control mode and in a tag mode according to a pulse sequence based on an ASL technique. The pulse sequence includes a velocity-selective pulse, BVS (Band-limited Velocity-Selective)-pulse, that selectively excites magnetization spins in a blood flow passing through the region to be imaged and having a constant velocity range for the spins to undergo transition to transverse magnetization, and then performs excitation to cause the transverse magnetization to flip back to longitudinal magnetization. The velocity-selective pulse is formed in such a manner that the transverse magnetization excited in each of the control mode and the tag mode gives rise to a phase shift in an opposite polarity upon velocity-selective excitation.

Abstract: In a process for speed-resolved flow measurement during a movement cycle in magnetic resonance tomography, an overview image (localizer) of a selected region of a living subject is acquired using an MRT-device, the overview image (localizer) is displayed on a screen, a quasi-simultaneous acquisition of an anatomical image series of the selected region and of a speed-resolved image series of a region identified within the selected region during the movement cycle, are performed, the two image series are displayed on the screen, and when displaying the image series, each speed-resolved image of the speed-resolved image series is integrated in the time-corresponding anatomical image of the anatomical image series.

Abstract: A method for compensation for object motion during scan, especially an magnetic resonance imaging (MRI) scan is provided. The method involves taking a first data set corresponding to a first focussed image and adding a number of data points to form a sligthly higher resolution image. The first data set is then used to predict what the next data points would be. The prediction can be performed in k-space, image space or in a hybrid space. The predicted data points arm then compared with the actual data points acquired as a means of determining any displacements. The displacements may be determined by comparing the phases of the actual and predicted data points and the k-space data corrected to compensate for any detected motion.

Abstract: For the purpose of improve rendering capability for a blood vessel, an MR. image producing method comprises: window-processing MR signals using a window function f(k) that has a “value less than one” at a center (O) and in its proximate region in a k-space and on a periphery and in its proximate region in the k-space, and has a value larger than the “value less than one” between the regions in which the window function has the “value less than one;” and applying Fourier-transformation processing to the window-processed MR signals to obtain an MR image.

Abstract: A method and system of correcting for a motion of an object are provided. In these system and method, the navigator data and map data are first obtained for the object. Then, the navigator data is compared with the map data to generate comparison data. Thereafter, a translation and/or a rotation of the object is corrected in real time as a function of the comparison data. The navigator can be preferably an octant navigator. In one exemplary embodiment, a scanning sequence can be used to determine a position of the object. This scanning sequence may include a signal portion which includes at least one radio frequency signal, an octant navigator portion which includes at least one octant navigator, and a spoiler portion provided for reducing a signal magnitude of the scanning sequence. The octant navigator is provided for allowing a measurement of at least one of the rotation and translation of the object. The navigator portion is advantageously provided between the signal portion and the spoiler portion.

Abstract: The present invention discloses a method and apparatus to make a nuclear magnetic resonance measurement on a flowing fluid using varied wait times. In one method, NMR measurements are made by: a) flowing the fluid through a static magnetic field; b) applying a group of oscillating magnetic field pulses to the flowing fluid, wherein the group of pulses is comprised of an initial pulse and one or more refocusing pulses; c) detecting magnetic resonance signals from the flowing fluid; d) after a wait time, repeating (b) and (c) one or more times, wherein at least two of the repetitions have varied wait times; and e) analyzing the detected magnetic resonance signals to extract information about the flowing fluid. Further, varied wait time measurements may be useful in determining the flow rate of the sample.

Abstract: A contrast enhancement (CE) agent is infused into blood flowing through a site that is to be imaged with magnetic resonance imaging (MRI). Two double inversion procedures are carried out, forming a quadruple inversion recovery (QIR) pulse sequence. Each double inversion procedure comprises a non-selective and slice-selective inversion RF pulse. The first double inversion procedure is followed by a first predefined inversion delay period, TI1, and the second procedure by a second predefined inversion delay period, TI2. A black-blood image can thus be produced in which blood appears consistently black and tissues surrounding the blood, such as a vessel wall, heart, atherosclerotic plaque, or thrombus, are clearly visible. Unlike the prior art black-blood imaging technique, the QIR method does not require a precise knowledge of the T1 of the blood carrying the CE agent in order to suppress the signal and artifacts caused by the blood flowing through the site.

Abstract: A system and method for adaptive averaging of velocity spectra using variable density trajectories, comprising: acquiring at least one series of velocity spectra using interleaved variable density trajectories and sampling low kv data more often or more densely than high kv data, the series of velocity spectra further comprising at least one spectrum; identifying a series of velocity spectra that comprises at least one velocity spectrum as a template, aligning at least one of the acquired series of velocity spectra with the template using low kv data; and averaging the aligned spectra, the averaging further comprising averaging the low kv data of the aligned spectra, and combining the averaged low kv data with the high kv data of the aligned spectra, wherein the combination produces enhanced spectra.

Abstract: A novel technique for velocity measurements (PC-SSFP) is disclosed that combines CINE Phase Contrast (PC) MRI and balanced Steady State Free Precession (SSFP) imaging. Flow encoding is performed without the introduction of additional velocity encoding gradients in order to permit data acquisition with short TR comparable to repetition times of typical SSFP imaging sequences. Sensitivity to through plane velocities is instead established by inverting (i.e. negating) all gradients along the slice select direction. Velocity sensitivity (venc) can be adjusted by altering the first moments of the slice select gradients. Disturbances of the SSFP steady state are avoided by acquiring different flow echoes in consecutively (i.e. sequentially) executed scans, each over several cardiac cycles, using separate steady state preparation periods. Comparison of phantom measurements with those from established 2D-CINE-PC MRI excellent correlation between both modalities.

Abstract: Apparatus and method for providing in-situ data of formation fluids at true reservoir conditions. The apparatus has NMR chamber of the flow-through type, so it is no longer necessary to divert a sample for the basic NMR analysis or transfer it uphole for laboratory analysis. The apparatus is preferably modular and is compatible with wireline tools configurable for a variety of sampling, testing and monitoring purposes. Fluid properties such as viscosity can be derived from diffusivities and relaxation times, as measured by NMR. Additional accuracy is provided in the downhole sampling process, and in the interpretation of NMR logs in real time at true reservoir conditions.

Abstract: A method and apparatus are provided for forming a magnetic resonance angiographic image of a human body. The method includes the steps of applying a plurality of spatially non-selective radio-frequency pulses to the body, varying a magnitude of a phase-encoded gradient through the body in conjunction with application of the plurality of spatially non-selective radio-frequency pulses and detecting magnetic resonance imaging data from the body based upon the spatially non-selective radio-frequency pulses and varied phase-encoded gradient.

Abstract: The present invention relates to a method and system for conducting a magnetic resonance fluid flow study by conducting a labeling procedure and a control procedure and combining datasets from those procedures to create a dataset for the fluid flow study. An amplitude modulated magnetic field gradient and amplitude modulated RF irradiation may be applied during a labeling procedure. Likewise, amplitude modulated RF irradiation may be applied during a control procedure. An amplitude modulated magnetic field gradient may also be applied during the control procedure.

Abstract: Magnetic resonance imaging uses a pulse sequence formed to include a pre-pulse, an RF excitation pulse, an encoding gradient pulse, and a reading gradient pulse. The encoding gradient pulse has an encoding amount determined to allow a data acquisition position in a k-space to be directed outward from a center of the k-space. A train of pulses including the RF excitation pulse, the encoding gradient pulse, and the reading gradient pulse is repeated to allow the number of times of data acquisition in the k-space to become larger as approaching to a central region of the k-space. The pre-pulse is formed to be reduced in an application rate to the RF excitation pulse as approaching to an outward position in the k-space. By way of example, this pulse sequence is used for contrast enhanced MRA carried out under a dynamic scan.

Abstract: The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.

Abstract: An NMR method of analyzing an analyte comprises feeding an analyte sample fluid to an NMR flow cell. The NMR flow cell comprises an RF microcoil operably associated with an enlarged containment region. The mobile phase of the analyte sample flowing through the NMR flow cell has a solvent gradient greater than 10% per minute. The analyte sample fluid can be fed to the NMR flow cell from an analyte extraction chamber, e.g., operative to perform liquid chromatography, capillary electrophoresis, or the like, especially a capillary-based analyte extraction chamber integrated in an NMR probe with the NMR flow cell. A sample volume is held in the NMR flow cell for equilibration less than 1 hour, preferably less than 30 minutes prior to actuating NMR analysis of the observe volume in the microcoil.

Abstract: A method of magnetic resonance imaging is provided. It includes supporting a subject in an examination region of an MRI scanner (A), and applying an EPI pulse sequence with the MRI scanner (A) to induce a detectable magnetic resonance signal from a selected region of the subject. The magnetic resonance signal are received and demodulated to generate raw data. Applied to the raw data are a pair of ghost reducing correction factors (&thgr;,&Dgr;). The pair of corrections factors (&thgr;,&Dgr;) included a phase correction (&thgr;) and a read delay (&Dgr;). The phase correction (&thgr;) compensates for phase errors in the raw data, and the read delay (&Dgr;) effectively shifts a data acquisition window (120) under which the raw data was collected to thereby align the raw data in k-space. The correction factors affect how data is loaded into k-space to generate k-space data, and the k-space data is subjected to a reconstruction algorithm to generate image data.

Abstract: An MRI apparatus is provided to quantify perfusion (microcirculatory blood flow in the tissue) in a region to be imaged in a subject based an ASL (arterial spin labeling) technique. The apparatus comprises imaging, storing, and flow quantifying units. The imaging unit performs a scan according to the ASL technique on the region so that image data is acquired from the region. The storing unit stores relationship information between a concentration of tracer (water) and a flow of the perfusion. The relationship is obtained on a two-compartment model that uses two compartments placed inside and outside of a flow of blood that diffuses into the tissue of the region and that considers temporal changes in the diffusion of the microcirculatory blood flow into the tissue. The flow quantifying unit quantifies the flow of the perfusion by applying an amount derived from the image data to the relationship information.