Abstract: An MRI pulse sequence control system includes a pulse sequence controller, a controller, and a performance monitor module. The pulse sequence controller generates pulse sequence control data. The controller controls scanner devices according to the control data. The performance monitor module monitors performance of the controller during an MRI scanning procedure and provides controller performance information to the pulse sequence controller. The pulse sequence controller modifies the control data in response to the controller performance information. The controller responds to the control data during the MRI scanning procedure. A process for detecting errors in an MRI scan process includes monitoring performance of the controller during the MRI scanning procedure. Controller performance information is provided to the scanning pulse sequence controller. Control data generated by the scanning pulse sequence controller is modified in response to the controller performance information.

Abstract: A method of eliminating unnecessary frequency components using a quadrature detector. The method includes converting an analog input signal into a digital signal f1(t), and the signal f1 (t) is delayed by a sampling time ? to form a signal f2 (t). Then, letting the reference frequency be ?0, the I- and Q-components in quadrature detection by the following expression: I={f2(t)*sin ?0t?f1(t)*sin ?0(t??)}/sin ?0? Q={f2(t)*cos ?0t?f1(t)*cos ?0(t??)}/sin ?0?.

Abstract: A probe head for nuclear magnetic resonance measurements is disclosed in which at least a first kind of nuclei with a first, higher resonance frequency and a second kind of nuclei with a second, lower resonance frequency are excited within a magnetic field. The probe head comprises a first input/output terminal for the higher resonance frequency and a second input/output terminal for the lower resonance frequency. A measuring coil cooperates with a sample. The measuring coil has a first terminal end and a second terminal end. The first terminal end is coupled to the first input/output terminal and the second terminal end is coupled to the second input/output terminal. A stop circuit tuned to signals of the higher resonance frequency is arranged between the second terminal end and the second input/output terminal. The stop circuit, further, comprises a line having a length equalling a quarter wave length of the higher resonance frequency. The first line is arranged in series with the measuring coil.

Abstract: An apparatus for MRI having an RF birdcage coil and an RF shield is disclosed. The RF birdcage coil includes a coil axis, an end ring portion disposed about the axis, and a plurality of legs disposed parallel to the axis and in signal communication with the end ring portion. The RF shield is disposed about the coil and is in signal communication therewith. The shield includes a cylindrical conductive sheet having first and second ends, and a plurality of sets of discontinuous slots disposed about the cylindrical sheet and running between the first and second ends, wherein a region of discontinuity within a set of the slots is aligned with the end ring portion.

Abstract: A capacitor decoupling network allows the production of a multi-loop local coil for magnetic resonance imaging without overlap of the loops and/or with decoupling between both adjacent and non-adjacent coils. The former design may find application for new MRI techniques such as SMASH and SENSE.

Abstract: In a magnetic resonance tomography method and apparatus for avoiding peripheral interference signals in magnetic resonance tomography when using spin-echo sequences, the average frequency and the bandwidth of the radio-frequency excitation pulse differ from the average frequency and the bandwidth of the radio-frequency refocusing pulse(s), and the amplitude of the slice selection gradients activated during the radio-frequency excitation pulse differing from the amplitude of the slice selection gradient(s) activated during the radio-frequency refocusing pulse, such that the excitation slice of the RF excitation pulse and the refocusing slice of the RF refocusing pulse(s) in the homogeneous volume (FOV) of the basic magnetic field are superimposed, while the excitation slice of the RF refocusing pulse(s) in the non-homogeneous volume of the basic magnetic field are separated locally, and an echo signal is thereby prevented in the non-homogeneous volume.

Abstract: The instant invention provides in-vivo methods and apparatus for radiation dosimetry assessment in individuals exposed to potentially harmful radiation, based on measurements in-situ of the teeth. The in vivo dosimetry assessment methods and apparatus utilize electron paramagnetic resonance (EPR) techniques; and employ an apparatus comprising an integrated EPR spectrometer system, an ergonomic magnet and a constructed resonator structure. In various aspects, the dosimetry assessment apparatus is configured to be easily portable and withstand potentially adverse mechanical effects of transportation and deployment in the field. The apparatus also is configured with a power supply that is compatible with both conventional AC line voltages and/or other sources of power suitable for field conditions; and may be easily operated by minimally trained technicians to quickly generate a readout of estimated radiation exposure dose.

Abstract: The present invention provides a system and method of MR scan prescription to achieve in a fast, simple, and effective manner the optimal peak excitation field strength for a given pulse shape and flip angle such that the minimum TR for the MR scan can be optimized and based on SAR constraints. The present invention provides a technique to obtain optimal B1 parameters for an arbitrary shape and flip angle of an excitation pulse in real-time while satisfying SAR and/or RF hardware limits to determine the minimum achievable repetition time for a pulse sequence. The present invention is particularly applicable with breath-hold and cardiac imaging techniques that are carried out at relatively high field strengths.

Abstract: A magnetic resonance apparatus with a radio-frequency shield at a reference potential, a detuning circuit and an electrical line which is connected with the detuning circuit. The electrical line is fashioned as a strip conductor and is attached to the radio-frequency shield. The strip conductor can be used for direct current/direct voltage supply of the detuning circuit. This has the advantage that the detuning circuit can be activated without exerting a significant interfering influence on the magnetic field in the magnetic resonance apparatus.

Abstract: A system and method for MR imaging with coil sensitivity or calibration data acquisition for reducing wrapping or aliasing artifacts is disclosed. Low resolution MR data representative of coil sensitivity of a coil arrangement within an FOV is acquired prior to application of an imaging data acquisition scan and is used to reduce wrapping or aliasing artifacts in a reconstructed image.

Abstract: The invention relates to a method of parallel imaging reconstruction in parallel magnetic resonance imaging reconstruction. Magnetic resonance data is acquired in parallel by an array of separate RF receiver coils. A reconstruction method based on Tikhonov regularization is presented to reduce the SNR loss due to geometric correlations in the spatial information from the array coil elements. In order to reduce the noise amplification of the reconstruction so-called “g-factor”, reference scans are utilized as a priori information of the final reconstructed image to provide regularized estimates for the reconstruction using the L-curve technique. According to the invention the method with the proposed L-curve approach was fully automatic and showed a significant reduction in average g-factors in the experimental images.

Abstract: A method of steady-state free precession MR imaging is provided that includes the steps of: (a) providing a balanced steady-state free precession imaging sequence that includes a plurality of phase encoding steps, wherein each phase encoding step comprises a phase encoding gradient and a slice selection gradient; and (b) acquiring imaging data by performing the plurality of phase encoding steps in sequence, wherein the imaging data is acquired is compensated for one or more effects due to eddy-currents, flow, or motion related artefacts due to the implementation of one or more artefact compensation strategies that consist of (i) “pairing” of consecutive phase encoding steps and of (ii) “through slice equilibration” of eddy-current and motion or flow related signal oscillations.

Abstract: An method for producing magnetic resonance imaging data is disclosed. An example embodiment of the method includes acquiring a series of M images at a plurality of echo times using a multi-echo pulse sequence. A compensation gradient is added as a blipped gradient in the slice direction before the first image acquisition and between each subsequent image acquisitions to compensate for static magnetic field inhomogeneities. The method also includes repeating the step of acquiring the series of M images N times. The compensation gradient is set to a predetermined value for each acquisition. The method further includes combining the N acquired images for each of the M echo times to obtain M corrected images, computing a map of T2* values from the M corrected images, and storing data representing the N acquired images and the M corrected images. Systems and computer readable media for implementing the method are also disclosed.

Abstract: An NMR apparatus, sample contained in a sample holder is ejected from an NMR probe to the top of the magnet region where a sample latching mechanism holds the sample in place without requiring a continuing flow of pressurized gas, electrical power or other outside force. The sample can then be removed and/or exchanged with another sample that is also held in place without the expenditure of gas. When ready the operator depresses a lever arm enabling the exchanged sample to move into the probe.

Abstract: A method (10) permits determining the temperature in a magnetic resonance check weighing system (24) of a sample in a container (22) on a production line at the time of magnetic resonance testing. Method (10) includes the steps of determining a time-temperature correction factor for the sample in the container (50), measuring the temperature of the composite sample and the container at a time other than the time of magnetic resonance testing (70), and applying the correction factor to the temperature of the composite sample and container at a time other than the time of magnetic resonance testing (80).