Systems and methods for pre-tuning a main Nuclear Quadrupole Resonance (NQR) probe using a forward sensing probe include a determination of an amount of resonance detuning of the forward sensing probe caused by a moving object entering a field of view of the forward sensing probe. The amount of resonance detuning is used to pre-tune the main probe such that when the moving object enters a field of view of the main probe, the main probe will move back into tune while delivering optimal power to the object for measurement and identification of a material therein.

The invention provides for a medical imaging system (100, 300). The medical imaging system comprises a processor (104). Execution of machine executable instructions (120) causes the processor to: receive (200) magnetic resonance imaging data (122) comprising a Z-spectrum acquisition (124) for a set of saturation frequency offsets (126) and at least one reference saturation frequency offset (128); reconstruct (202) saturation frequency offset complex image data (130); reconstruct (204) a B0 map (132), a water image (134), and a fat image (136) according to a Dixon-type magnetic resonance imaging protocol; calculate (206) a water phase angle (138) using the water image and/or the fat image; calculate (208) rotated complex image data (140) by rotating the phase of the saturation frequency offset complex image data such that the complex water signal is aligned with a real axis for each voxel; perform (210) a B0 correction by calculating shifted complex image data (142); calculate (212) a frequency dependent phase angle (144) descriptive of a phase angle between the complex water signal and the complex fat signal for each of the set of saturation frequency offsets using a fat signal model comprising at least two fat species; calculate (214) a residual fat component correction factor (150) by projecting the complex fat signal onto the real axis for each of the set of saturation frequency offsets; and calculate (216) corrected water Z-spectrum image data (152) by subtracting the residual fat component correction factor for each of the set of saturation frequency offsets from the real component of the shifted complex image data.

A method may include obtaining image data of a subject acquired by an imaging device. The method may also include determining one or more characteristics associated with a body part of the subject from the image data. The one or more characteristics of the body part of the subject may include at least one of position information of the body part in the subject, geometric morphology information of the body part, water content information, or fat content information. The method may also include determining, based on one or more characteristics associated with the body part, values of one or more individualized parameters corresponding to the subject. The method may further include causing the imaging device to perform an imaging scan on the subject according to the values of the one or more individualized parameters.

Some aspects comprise a tuning system configured to tune a radio frequency coil for use with a magnetic resonance imaging system comprising a tuning circuit including at least one tuning element configured to affect a frequency at which the radio frequency coil resonates, and a controller configured to set at least one value for the tuning element to cause the radio frequency coil to resonate at approximately a Larmor frequency of the magnetic resonance imaging system determined by the tuning system. Some aspects include a method of automatically tuning a radio frequency coil comprising determining information indicative of a Larmor frequency of the magnetic resonance imaging system, using a controller to automatically set at least one value of a tuning circuit to cause the radio frequency coil to resonate at approximately the Larmor frequency based on the determined information.

A fully sampled calibration data set, which may be Cartesian k-space data, is used to obtain targeted and optimal interpolation kernels for non-regularly sampled data. The calibration data are self-calibration data obtained from a time-averaged image, or re-sampled data. ACS data are resampled for calibration of region-specific kernels. Subsequently, an explicit noise-based regularized solution can be utilized to estimate region-specific kernels for reconstruction.

A system and method are provided for operating a magnetic resonance tomograph. A transmitter of the magnetic resonance tomograph transmits a predetermined test pulse with a reduced power. The magnetic resonance tomograph receives the test pulse with the local coil. A controller compares the received test pulse with a predetermined pulse response and emits a warning signal when the received test signal differs from the predetermined pulse response.

Some aspects comprise a tuning system configured to tune a radio frequency coil for use with a magnetic resonance imaging system comprising a tuning circuit including at least one tuning element configured to affect a frequency at which the radio frequency coil resonates, and a controller configured to set at least one value for the tuning element to cause the radio frequency coil to resonate at approximately a Larmor frequency of the magnetic resonance imaging system determined by the tuning system. Some aspects include a method of automatically tuning a radio frequency coil comprising determining information indicative of a Larmor frequency of the magnetic resonance imaging system, using a controller to automatically set at least one value of a tuning circuit to cause the radio frequency coil to resonate at approximately the Larmor frequency based on the determined information.

A method of setting an RF operating frequency of an MRI system (1) uses a first reference frequency signal, obtained from a geo-satellite positioning system, as a stable long term frequency reference. A second frequency source (24) is calibrated using the first frequency reference signal and the second frequency reference source (24) is then used as the master clock for the MRI system (1), for setting the RF operating frequency.

A method of operating a multi-coil magnetic resonance imaging system is disclosed which includes a controller performing a simulation using a predefined tissue model, determining output values of a variable of interest (VOI) associated with operation of two or more coils of an MRI system based on the simulation, comparing the simulated output values of the VOI to an a priori target values of the VOI, if the simulated output values of the VOI are outside of a predetermined envelope about the a priori target values of the VOI, then performing an optimization, wherein the optimization includes iteratively adjusting the circuit values until the simulated output values of the VOI are within the predetermined envelope about the a priori target values of the VOI thereby establishing VOI optimized values, and loading the established VOI optimized values and operating the magnetic resonance imaging system on the tissue to be imaged.

A method for NMR measurements on borehole materials, e.g., sidewall cores, is based on performing a standard measurement in substantially homogeneous magnetic fields with a sensitivity volume covering an entire sample and a measurement on a fragment of the sample (local measurement), the fragment having a predetermined volume independent of the irregularities of the sample shape (e.g., irregular shaped edges). The fragment of the sample is selected using a switchable static magnetic field gradient or a localized radio-frequency magnetic field. The homogeneous and the local measurement data are processed jointly to obtain volume normalized NMR relaxation data (in porosity units), the processing also using a calibration sample data. A measurement apparatus with an automated sample transfer can be used to implement the method in order to perform high-throughput NMR relaxation measurements that do not require independent measurement of the sample volume.