Abstract: A fat suppressed diffusion image determination apparatus, a corresponding method and a corresponding computer program determine a diffusion weighted magnetic resonance image (DWI) of an object. The fat suppressed diffusion image determination apparatus includes a diffusion reference image providing unit for providing a diffusion reference MR image of the object, a fat image determination unit for determining a fat image from the diffusion reference MR image, a diffusion weighted image providing unit for providing a diffusion weighted MR image of the object, a fat suppressed image determination unit for determining a fat suppressed diffusion weighted MR image using a combination of the diffusion weighted MR image and the fat image.

Abstract: A medical information processing apparatus according to an embodiment includes processing circuitry. The processing circuitry calculates noise intensity from first data acquired during a first scan. The processing circuitry calculates a denoising intensity used for a denoising process based on the noise intensity and the difference between an imaging condition for the first scan and an imaging condition for a second scan, the denoising process being applied to second data obtained by the second scan.

Abstract: A method and device for detection of solid organic matter and fluids in a shale rock by means of low field Nuclear Magnetic Resonance (NMR) in a single measurement, by submitting a rock sample to a 2D NMR assay comprising applying a 2D pulse sequence with a saturation-recovery, or inversion-recovery, in an indirect dimension and an FID-CPMG in a direct dimension. The method can be used as an analytical technique for rock samples from unconventional hydrocarbon reservoirs.

Abstract: A method and an apparatus are provided for determining a valid parameter dataset for a protocol for an MRT examination by a MRT facility. The apparatus includes an input facility for importing a set of parameters to be used for performing the MRT examination; an interface for capturing at least one system value which represents an availability of a system resource for the MRT examination; a processor for calculating system resources required to perform the MRT examination using the imported parameters, and for executing a prepare function, which checks whether, with regard to the captured system values, the imported parameters are implementable in the MRT examination. If the parameters are not implementable, the processor is configured to calculate a modifying function for modifying the imported parameters based on the current system values and the required system resources and modify the imported parameters in accordance with the calculated modifying function.

Abstract: Techniques are disclosed based on balanced steady state free precession sequence. The techniques include determining a readout gradient of climbing period, platform period, and descent period, and performing a balanced steady state free precession sequence in which the readout gradient is applied in the readout direction, the analog-to-digital conversion module for collecting k-space data is activated during the climbing period maintained in the on state during the platform period, and deactivated during the descent period. The technique includes converting the k-space data collected by the analog-to-digital conversion module into uniform k-space data and generating a magnetic resonance image based on the uniform k-space data. The techniques yield more running time of the readout gradient for data acquisition, reduce the data reading time, and shorten the scanning time. The techniques also reduce the accumulated phase of the field non-uniformity in the echo interval to reduce black band artifacts.

Abstract: A method, electromagnet device, and system for reducing a higher order term of a concomitant field in an imaging magnetic field during magnetic resonance imaging is described. The electromagnet system has a first shim coil configured to be driven to generate a first compensation magnetic field during imaging according to a first second-order compensation term, the first compensation magnetic field having a similar amplitude but opposite direction as that of a first second-order concomitant magnetic field.

Abstract: A system for medical data acquisition comprising a plurality of scanners and a plurality of infrastructure units to operate the scanners, wherein the system is designed to use at least one of the infrastructure units as a common infrastructure unit to operate at least two of the scanners. Also, a method to control this system.

Abstract: Embodiments of the present application provide a magnetic resonance system and a transmission apparatus, a transmission method, and a pre-scanning method. The apparatus includes: a signal output unit used to generate and output a pulse signal; a radio-frequency amplifier used to amplify the pulse signal; a signal processing unit used to transmit, to a transmit coil of the magnetic resonance system, the signal amplified by the radio-frequency amplifier, receive and adjust a phase of the feedback signal, and output the phase-adjusted feedback signal to the signal output unit; and a determination unit used to acquire amplitude values of the feedback signal at different phases, and determine a forward power and/or a reverse power according to the amplitude values of the feedback signal at the different phases.

Abstract: In a method for recording diffusion-weighted measurement data, using a MR system with diffusion weightings with two+ different b-values, diffusion directions and diffusion weightings with the associated b-values to be used for the desired recordings are loaded, a sequence of recordings of measurement data to be recorded consecutively are determined by sorting the diffusion directions and diffusion weightings to be recorded based on their associated b-value, such that the b-value of a recording of measurement data is less than the b-value of the immediately preceding recording of measurement data by no more than a predetermined threshold value, and the recordings are recorded based on the determined sequence. By arranging diffusion encodings for the desired recordings to be used consecutively, abrupt discontinuities in the b-values used chronologically are prevented, thereby eddy current effects from preceding recordings have time to abate in the case of recordings with small b-values.

Abstract: In a method and system for the generation of measurement data required k-space is read out in the readout direction in k-space rows such that at least a first k-space row of the k-space rows does not cover the k-space to be read out in the readout direction in full and at least a second k-space row of the k-space rows covers the k-space to be read out in locations in the readout direction at which the first k-space row does not cover the k-space to be read out. Measurement data that is missing in the k-space is completed in this way on the basis of recorded echo signals stored as measurement data.

Abstract: According to some aspects, a method of suppressing noise in an environment of a magnetic resonance imaging system is provided. The method comprising estimating a transfer function based on multiple calibration measurements obtained from the environment by at least one primary coil and at least one auxiliary sensor, respectively, estimating noise present in a magnetic resonance signal received by the at least one primary coil based at least in part on the transfer function, and suppressing noise in the magnetic resonance signal using the noise estimate.

Abstract: A method for generating a dual-class dataset is disclosed. A single-class dataset and a context dataset are obtained. The context dataset can be labeled. A model can be trained using the combination of the single-class dataset and the labeled context dataset. The model can be run on the context dataset. The data points that are classified the same as the data points included in the single-class dataset, can be removed from the labeled context dataset and added to the single-class dataset. These steps can be repeated until no data points are classified by the model.

Abstract: A pulse-design unit for creating pulse data for controlling a magnetic resonance system includes a data interface configured for receiving an examination scheme, and a calculation module configured for generating pulse data based on an examination scheme. The pulse-design unit includes a data grid and/or parameter values created from map pairs of a plurality of patients and is configured to select and/or calculate pulse data using the data grid and/or parameter values and a provided examination scheme. A method and a control device for controlling a magnetic resonance imaging (MRI) system and a related magnetic resonance imaging system are also provided.

Abstract: One embodiment provides a method for controlling a microagent in a workspace. The method includes providing a plurality of magnetic sources and generating a rotating gradient magnetic field by activating the plurality of magnetic sources differently such that a driving force is created to drive the microagent towards an aggregation center in the workspace.

Abstract: An example method includes registering, via a visualization device, a virtual model of a portion of an anatomy of an ankle of a patient to a corresponding portion of the anatomy of the ankle viewable via the visualization device, the virtual model obtained from a virtual surgical plan for an ankle arthroplasty procedure to attach a prosthetic to the anatomy. The example method also comprises displaying, via the visualization device and overlaid on the portion of the anatomy, a virtual guide that guides at least one of preparation of the anatomy for attachment of the prosthetic or attachment of the prosthetic to the anatomy.

Abstract: An assembly for providing a B0 magnetic field for a magnetic resonance imaging (MRI) system, the assembly comprising: a plurality of rods extending along a common longitudinal direction and positioned to form a bore extending along the common longitudinal direction, the plurality of rods including a first rod, the first rod comprising: ferromagnetic segments, each having a net magnetization in a plane that is substantially perpendicular to the common longitudinal direction; and non-ferromagnetic segments.

Abstract: An excitation region setting method according to an embodiment includes: receiving a designation of a first region from a user, the first region being designated in a distortion-corrected image that is a magnetic resonance image in which an effect of a distortion of a magnetic field has been corrected; calculating an actual excitation region where a subject is to be excited, based on the designated first region and the effect of the distortion of the magnetic field; and correcting imaging conditions including at least one of an orientation of a slice plane that defines the actual excitation region, or a frequency of a high-frequency magnetic field applied to the subject, in such a manner that the calculated actual excitation region becomes closer to an ideal excitation region represented as the first region.

Abstract: In a method for correcting influences on magnetic resonance imaging of an examination object caused by fluctuations in a basic magnetic field, an MR data set is generated for two or more measurement periods, and a regression analysis is performed. Each of the MR data sets may contain at least one two-dimensional individual data set. The regression analysis may determine at least one phase correction value for a measurement period to be corrected. Two or more different individual data sets may be taken into account in the analysis. An MR image may generated based on the MR data sets and the at least one phase correction value.

Abstract: Techniques are disclosed for capturing scan data of an examination object via a magnetic resonance system. The techniques include capturing a first set of a diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a first echo signal, wherein before the acquisition phase in a diffusion preparation phase, diffusion gradients are switched for diffusion encoding of the scan data, The techniques additionally include capturing a second set of non-diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a second echo signal, wherein before the acquisition phase, in a diffusion preparation phase, the same diffusion gradients are switched as are switched for diffusion encoding of the scan data of the first set of diffusion-weighted scan data, although they have no influence on the second echo signal. Diffusion-weighted and non-diffusion-weighted scan data is thereby captured, having identical disturbances caused by eddy currents induced by switched gradients.

Abstract: A chiral molecule can be defined as a molecule that has a non-superimposable mirror image. These mirror images can be referred to as enantiomers. The enantiomers generally have the same set of bond lengths and bond angles in their three-dimensional geometry. Apparatus and techniques described herein can be used to perform analysis of chiral molecules using cavity-enhanced molecular rotational spectroscopy. A sample cell can define a resonant cavity, and a sample introduction port can provide pulse-jet injection of an analyte molecule and a chiral tag to allow analysis of a complex comprising the analyte and chiral tag.

Abstract: A local coil for an MRI scanner, an MRI scanner and a method for operating the MRI scanner are provided. The local coil includes a plurality of n antenna coils and at least one analog-to-digital converter having a signal link to the antenna coils. The local coil includes a compression device configured to compress the n digital input data streams into m digital output data streams. The n digital input data streams are mapped to an m-dimensional space with m base vectors.

Abstract: Techniques are described for acquiring MR data comprising first MR data and second MR data of an examination object using an MR control sequence and a magnetic resonance device comprising an amplifier unit and an analog-to-digital converter (ADC).

Abstract: Systems and methods involving: a housing having a bore in which a subject to be imaged is placed; a main magnet configured to generate a volume of magnetic field within the bore, the volume of magnetic field having inhomogeneity below a defined threshold; gradient coils configured to linearly vary the volume of magnetic field as a function of spatial location; pulse-generating coils configured to generate and apply radio frequency (RF) pulses to the volume of magnetic field in sequence to scan the portion of the subject; shim gradient coils configured to perturb a spatial distribution of the linearly varying volume of magnetic field; and a control unit configured to operate the gradient coils, pulse-generating coils, and shim gradient coils such that only the user-defined region within the volume of magnetic field is imaged.

Abstract: The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of a MR device (1). It is an object of the invention to enable fast spiral MR imaging with a defined T2 contrast.

Abstract: Systems and Methods that identify the effect of motion during a medical imaging procedure. A neural network is trained to translate motion induced deviations of a coil-mixing matrix relative to a reference acquisition into a motion score. This score can be used for the prospective detection of the most corrupted echo trains for removal or triggering a replacement by reacquisition.

Abstract: A system and method is provided for controlling physiological-noise in functional magnetic resonance imaging using raw k-space data to extract physiological noise effects. The method can identify these effects when they are separable and directly reflects the artefactual effects on fMRI data, without the need for external monitoring or recording devices and to be compensated for via rigorous statistical analysis modeling of such noise sources. The physiological fluctuations may be treated as global perturbations presented around the origin point in a k-space 2D slice. Each k-space 2D slice may be acquired at a very short repetition time with an effective sampling rate to sample cardiac and respiratory rhythms through proper reordering and phase-unwarping techniques applied to the raw k-space data.

Abstract: A method for correcting TOF MR data, including providing a coil sensitivity map for an examination region of an examination object, providing the TOF MR data of the examination region, and generating corrected TOF MR image data comprising multiplying the TOF MR data by an inverse of the coil sensitivity map.

Abstract: In a method for acquiring measurement data using a magnetic resonance (MR) system having a gradient unit, frequency-dependent parameters characterizing the gradient unit of the MR system are accessed (e.g. loaded from a memory), a k-space trajectory of a RESOLVE (Readout Segmentation Of Long Variable Echo trains) sequence planned for a MR measurement is accessed, MR measurement data is acquired based on the planned k-space trajectory and reconstructing image data from the MR measurement data, and an electronic signal is provided that represents the reconstructed image data as an output of the MR system. The k-space trajectory may have a frequency component in at least one direction. The planned k-space trajectory may be corrected based on at least one frequency component of the planned k-space trajectory and the frequency-dependent parameters.

Abstract: A magnetic resonance imaging apparatus according to an embodiment includes processing circuitry. The processing circuitry acquires an echo signal generated for each of intervals of repetition time by applying an excitation pulse to a subject at the intervals of repetition time, and acquires data of a plurality of trajectories set for a k-space using the echo signals. The processing circuitry acquires a plurality of echo signals by setting echo time to lengths different between a plurality of periods of repetition time and acquires data of the same trajectory using the echo signals, and the echo time serves as time from application of the excitation pulse to generation of the echo signal.

Abstract: An X-ray detector unit is disclosed. In an embodiment, the X-ray detector unit includes: at least one analysis unit to process electrical signals delivered from a coupled converter unit and operatable by an operating voltage; an adjustable voltage supply, coupled to the at least one analysis unit, to provide an adjustable supply voltage; an identification unit, assigned to the at least one analysis unit, to provide identification information about the at least one analysis unit in a readable manner; and a communication unit, coupled to the adjustable voltage supply, to read the identification information provided from the identification unit, and based upon the identification information provided, to adjust the adjustable voltage supply to equate the provided supply voltage to the operating voltage of the at least one analysis unit.

Abstract: In a Method and a device for magnetic resonance imaging of a subject using a spoiled gradient echo sequence, a B0 magnetic field strength of at most 1.5 T is used during the sequence. As part of the sequence a slice select gradient acting as a spoil gradient is played out. Substantially simultaneously with the slice select gradient a predetermined RF pulse is played out in the sequence, wherein a time-bandwidth product of the RF pulse is set so that a majority of the energy of the RF pulse is transmitted in its central main lobe.

Abstract: Embodiments of the present invention provide a method for acquiring and processing magnetic resonance data, a magnetic resonance imaging system and method, and a computer-readable storage medium. The method for acquiring and processing magnetic resonance data comprises: populating, to a K-space, a plurality of sets of echo data acquired from a plurality of excitations of a tissue to be imaged, wherein at least two of the plurality of sets of echo data have opposite K-space populating orders; and reconstructing an image based on the echo data populated to the K-space.

Abstract: During operation, a computer system may acquire magnetic resonance (MR) signals associated with a sample from a measurement device or memory. Then, the computer system may access a predetermined set of coil magnetic field basis vectors associated with a surface surrounding the sample, where coil sensitivities of coils in the measurement device are represented by weighted superpositions of the predetermined set of coil magnetic field basis vectors using coefficients, and where the predetermined coil magnetic field basis vectors are solutions to Maxwell's equations. Next, the computer system may solve, on a voxel-by-voxel basis for voxels associated with the sample, a nonlinear optimization problem for MR information associated with the sample and the coefficients using: a forward model that uses the MR information as inputs and simulates response physics of the sample, the MR signals and the predetermined set of coil magnetic field basis vectors.

Abstract: The invention provides for a magnetic resonance imaging system (100, 200) comprising a memory (148) for storing machine executable instructions (150) and pulse sequence commands (152). The pulse sequence commands are configured for acquiring a four dimensional magnetic resonance data set (162) from an imaging region of interest (109). The four dimensional magnetic resonance data set is at least divided into three dimensional data magnetic resonance data sets (400, 402, 404, 406, 408) indexed by a repetitive motion phase of the subject. The three dimensional data magnetic resonance data sets are further at least divided into and indexed by k-space portions (410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430, 432, 434, 436). The magnetic resonance imaging system further comprises a processor (144) for controlling the magnetic resonance imaging system.

Abstract: The disclosure facilitates determining patient motion during a magnetic resonance protocol. According to some examples, the patient motion may be corrected or compensated.

Abstract: In a method for recording measurement data, frequency-dependent parameters characterizing a gradient unit are loaded, a k-space trajectory planned for a MR measurement and having at least one frequency component is loaded, MR measurement data is acquired based on the planned k-space trajectory and reconstructing image data from the MR measurement data, wherein the planned k-space trajectory is corrected based on the at least one frequency component of the planned k-space trajectory and the frequency-dependent parameters, and an electronic signal representing the reconstructed image data is provided as an output of the MR system. The reconstructed image data may be stored and/or displayed. Advantageously, the correction can be employed flexibly for k-space trajectories with different frequency components.

Abstract: In a method for automatic control of an examination sequence in magnetic resonance (MR) system during recording of MR signals in an examination segment of a person being examined, which has two tissue components with two different MR resonant frequencies, an examination sequence for examination of the examination segment is determined. Further, whether the examination sequence includes an imaging sequence in which one of the two tissue components is to be suppressed and for which at least two different suppression options exist to reduce the one of the two tissue components during the recording of the MR signals is determined. In response to the determination that the examination sequencing included the imaging sequence, the method can include determining a sequence parameter of the examination for the imaging sequence; and selecting one of the at least two suppression options as a function of the sequence parameter determined for the imaging sequence.

Abstract: To provide a technique with which a FLAIR image and a T1-weighted image can be acquired in a short scan time, a magnetic resonance imaging apparatus comprises: an RF driver unit 121 for driving an RF coil unit 103; a gradient coil driver unit 122 for driving a gradient coil unit 102; and a controller unit 124 connected to the RF coil driver unit 121 and gradient coil driver unit 122, for controlling them so that an imaging sequence ISc having a duration of 1TR for generating echoes from a body part being imaged is repetitively executed, where the imaging sequence ISc has a first sequence part SQ1 including an inversion pulse 11 and an FSE sequence 12, and a second sequence part SQ2 including an inversion pulse 21 and a GRE sequence 22.

Abstract: In a method for generation of a homogenization field suitable for homogenization of magnetic resonance data of an examination object, first magnetic resonance data from an examination region of the examination object is provided, a trained function is provided, a homogenization field is extracted by processing the first magnetic resonance data by way of the trained function, and the homogenization field is provided.

Abstract: The present invention provides an apparatus and a corresponding method useful for electron paramagnetic resonance imaging, in situ and in vivo, using high-isolation transmit/receive (TX/RX) coils, which, in some embodiments, provide microenvironmental images that are representative of particular internal structures in the human body and spatially resolved images of tissue/cell protein signals responding to conditions (such as hypoxia) that show the temporal sequence of certain biological processes, and, in some embodiments, that distinguish malignant tissue from healthy tissue. In some embodiments, the TX/RX coils are in a surface, volume or surface-volume configuration.

Abstract: The invention provides for a magnetic resonance imaging system (100) for acquiring magnetic resonance data (142) from a subject (118) within a measurement zone (108). The magnetic resonance imaging system (100) comprises: a processor (130) for controlling the magnetic resonance imaging system (100) and a memory (136) storing machine executable instructions (150, 152, 154), pulse sequence commands (140) and a dictionary (144). The pulse sequence commands (140) are configured for controlling the magnetic resonance imaging system (100) to acquire the magnetic resonance data (142) of multiple steady state free precession (SSFP) states per repetition time. The pulse sequence commands (140) are further configured for controlling the magnetic resonance imaging system (100) to acquire the magnetic resonance data (142) of the multiple steady state free precession (SSFP) states according to a magnetic resonance fingerprinting protocol. The dictionary (144) comprises a plurality of tissue parameter sets.

Abstract: A method and apparatus for determining spatial distribution of a complex radio frequency (RF) of both transmit field and receive sensitivity a magnetic resonance imaging (MRI) system. The method includes estimation of the absolute phase of transmit field using a reference transmit coil or array coils with minimal absolute phase. The method and apparatus include estimation of complex receive sensitivity of a transceiver coil using the complex transmit field of the transceiver coil or array coils.

Abstract: A method for analyzing unconventional rock samples using nuclear magnetic resonance (NMR), tracking fluid change in the rock sample over a time period, calculating transverse relaxation time (T2) generating fluid distribution profiles by the computer processor and based on a NMR imaging, where the fluid distribution profiles representing a movement of the fluid, and obtaining, quantification of fracture volume by the computer processor and based on the NMR imaging.

Abstract: There are provided a parallel rapid imaging method and device based on a complex number conjugate symmetry of multi-channel coil data and nonlinear GRAPPA image reconstruction, and a medium. The imaging method includes: obtaining virtual conjugate coil data by expanding the actual multi-channel coil data; combining actual multi-channel coil data and virtual multi-channel coil data to obtain a linear data term and a nonlinear data term; calibrating weighting factors of the linear data term and the nonlinear data term by using combined low-frequency full-sampling data (margins of the low-frequency full-sampling data includes parts of high-frequency data); reconstructing data which is under-sampled in a high-frequency region according to the calibrated weighting factors; fusing the low-frequency full-sampling data and the reconstructed data for the high-frequency region.

Abstract: Embodiments of a compact portable nuclear magnetic resonance (NMR) device are described which generally include a housing that provides a magnetic shield; an axisymmetric permanent magnet assembly in the housing and having a bore, a plurality of magnetic elements that together provide a well confined axisymmetric magnetization for generating a near-homogenous magnetic dipole field B0 directed along a longitudinal axis and providing a sample cavity for receiving a sample, and high magnetic permeability soft steel poles to improve field uniformity: a shimming assembly with coils disposed at the longitudinal axis for spatially correcting the near homogenous magnetic field B0; and a spectrometer having a control unit for measuring a metabolite in the sample by applying magnetic stimulus pulses to the sample, measuring free induction delay signals generated by an ensemble of hydrogen protons within the sample; and suppressing a water signal by using a dephasing gradient with frequency selective suppression.

Abstract: Methods and systems for deep learning based image reconstruction are disclosed herein. An example method includes receiving a set of imaging projections data, identifying a voxel to reconstruct, receiving a trained regression model, and reconstructing the voxel. The voxel is reconstructed by: projecting the voxel on each imaging projection in the set of imaging projections according to an acquisition geometry, extracting adjacent pixels around each projected voxel, feeding the regression model with the extracted adjacent pixel data to produce a reconstructed value of the voxel, and repeating the reconstruction for each voxel to be reconstructed to produce a reconstructed image.

Abstract: To operate a magnetic resonance tomography system, first analysis signals are received by a main receive antenna and an auxiliary receive antenna. Based thereon, a first interference source and first weighting factors are determined. Second analysis signals are received by the main receive antenna and the auxiliary receive antenna and in accordance with the first weighting factors, a combination of the second analysis signals is created. Based thereon, a second interference source is determined. Second weighting factors are determined in order to suppress the influence of the first interference source and an influence of the second interference source. A magnetic resonance signal is received during an examination phase by the main receive antenna and an interference signal by the auxiliary receive antenna. An interference-suppressed magnetic resonance signal is created as a combination of the magnetic resonance signal and the interference signals depending on the second weighting factors.

Abstract: A head coil assembly includes a housing with a lower portion, an upper portion, a left portion, and a right portion, wherein each portion includes two or more radio-frequency (RF) coils, wherein the portions are sized and shaped to adjustably conform to a curvature of the subject's head for magnetic resonance (MR) imaging of the subject's head placed inside the housing, wherein the portions are operable to transition from an open position where the portions are sufficiently apart from each other to a closed position where the portions are adjusted to tighten a wrap around the subject's head along the curvature, and wherein the two or more RF coils in each portion are disposed in such manner that when the portions are operated to transition from the open position to the closed position, the RF coils of each portion remain decoupled to each other even along edges of each portion.

Abstract: There is provided a patient's cranial position monitoring and controlling device for controlling a magnetic resonance (MR) guided radiation source module via an MR-guided radiation controlling device connected to the patient's cranial position monitoring and controlling device and an MR-guided radiation system including a patient's cranial position monitoring and controlling device, which allows for better MR-imaging while allowing patient position monitoring close to the patient.

Abstract: A magnetic resonance imaging (MRI) system and method for acquiring magnetic resonance (MR) images using a pulse sequence implementing driven equilibrium and quadratic phase cycling techniques is provided. The method includes, during a pulse repetition period of a pulse sequence and using a quadratic phase cycling scheme, applying a first RF pulse to deflect a net magnetization vector associated with the subject from a longitudinal plane into a transverse plane; after applying the first RF pulse, applying a first sequence of RF pulses each of which flips the net magnetization vector by approximately 180 degrees within the transverse plane; and after applying the first sequence of RF pulses, applying a second RF pulse to deflect the net magnetization vector from the transverse plane to the longitudinal plane.