11 results about "B1 field" patented technology

The present disclosure describes systems and methods of magnetic resonance imaging (MRI) that provide B1 field mapping and B1 field spoiling without a plurality of B0 gradient fields. An off-resonant pulse may be applied, or delivered, to the object of interest following an excitation pulse to induce a phase shift, which may be measured to determine the B1 field map. Also, a spoiling off-resonant RF pulse may be applied, or delivered, to the object of interest to remove unwanted signal coherence pathways in the region of the object.

The invention discloses a CEST magnetic resonance imaging method and equipment, and relates to the technical field of CEST magnetic resonance imaging. The method comprises the following steps: acquiring first Z-spectrum data and second Z-spectrum data at a target frequency offset, and acquiring a B1 distribution diagram and a structure image; performing B1 field correction at least based on the first Z-spectrum data, the second Z-spectrum data and the B1 distribution diagram through the plurality of branches to obtain a plurality of CEST images; predicting a fusion mask based on an intermediate variable by using the trained fusion model, the intermediate variable being obtained according to the first Z-spectrum data, the second Z-spectrum data, the B1 distribution diagram and the structure image; and fusing the plurality of CEST images based on the predicted fusion mask to obtain a final CEST image. Therefore, correction time consumption can be reduced while the correction effect is ensured, and the method is suitable for CEST magnetic resonance imaging with high exchange rate and large effective saturation.

The embodiment of the present application discloses a method and device for limiting radio frequency alternating magnetic field in magnetic resonance imaging. The method comprises: measuring the vertical distance between a local coil placed on the scanned part of a patient and the center of the detection hole of a magnetic resonance (MR) scanner; determining the deviation between the field strength of the B1 field at the position of the local coil and the field strength of the B1 field at the center of the detection hole according to the vertical distance; calculating the conversion coefficient between the field strength of the B1 field at the position of the local coil and the field strength of the B1 field at the center of the detection hole according to the deviation; and calculating the maximum allowable field strength of the B1 field at the center of the detection hole according to the field strength of the B1 field required when the surface temperature of the local coil is equal to the upper limit of the safe temperature and the conversion coefficient. The embodiment of the present application can limit the B1 field in a smaller but still effective field strength range, thereby reducing the waste of the performance of the B1 field while ensuring the safety of the patient and the quality of the MR imaging.

A method is provided for determining a movement-corrected B1 field map on contrast medium injection, wherein before the injection, a B1 field map is determined. Following the contrast medium administration, a position change is determined at the position at which the B1 field map was determined. With the position change and the B1 field map, the movement-corrected B1 field map is determined.

The invention relates to a transmitting coil device and a magnetic resonance radio frequency field transmitting system. The transmitting coil device comprises at least two loop groups arranged in the axial direction, each loop group comprises a plurality of loops arranged in the circumferential direction of the loop group, and each loop comprises two crosspiece parts arranged in the circumferential direction and two end parts connected with the two ends of the two crosspiece parts respectively; the loop group comprises a first loop group and a second loop group, and a first loop on the first loop group and a second loop on the second loop group share at least part of the end part. In the embodiment of the invention, the plurality of loop groups are arranged in the axial direction, and each loop group comprises a plurality of loops, so that the multi-row multi-channel transmitting coil device is obtained, and the uniformity of a B1 field in a cross section, a coronal view and a sagittal view can be realized.

The embodiment of the present application discloses a method and device for limiting radio frequency alternating magnetic field in magnetic resonance imaging. The method comprises: obtaining a first B1 field intensity required when a local coil surface temperature reaches a maximum safe temperature in a thermal equilibrium state when the local coil is placed at a set position in a detection hole of an MR scanner; obtaining a second B1 field intensity required for heating the local coil surface temperature to the maximum safe temperature within a set MR total scanning time when the local coil is placed at the set position according to a relationship among the local coil surface temperature, the scanning time and the B1 field intensity during MR scanning and the first B1 field intensity; and determining a third B1 field intensity required for MR scanning using the set MR total scanning time according to the second B1 field intensity. The embodiment of the present application reduces waste of B1 field performance while ensuring patient safety and improving MR imaging quality.

The present application provides a method, apparatus, terminal, and medium for simultaneous quantitative magnetic resonance imaging of a free-breathing heart using multiple parameters. Based on an established corresponding simultaneous quantitative magnetic resonance sequence, the cardiac tissue of a subject under free breathing is scanned to obtain a magnetic resonance scan image, which is then processed to obtain a processed magnetic resonance scan image. The processed magnetic resonance scan image is matched with an established dictionary to obtain a parameter set map of the subject's cardiac tissue. The method of the present invention solves the problem in the prior art of being unable to simultaneously measure parameters such as T1, T2, and T1ρ of cardiac tissue under free breathing, as well as the problem of being unable to simultaneously correct the effect of an inhomogeneous B1 field on parameter measurement.

For data analytics in magnetic resonance (MR) scanning, the scanning configuration information and the resulting raw data are directly used to determine the analytics or clinical decision. Artificial intelligence provides a value for a clinical finding characteristic of the patient based on the raw data from scanning and the controls used to scan, allowing the value to be based on all of the information content of the scan results. Reconstruction is not needed, allowing for simpler hardware, such as hardware with less homogeneous B0 and / or B1 fields than the norm and / or non-linear gradients.

The application relates to the technical field of magnetic resonance imaging, in particular to a nonlinear multi-configuration magnetic resonance imaging signal-to-noise ratio enhancement device and method, which comprises the following steps: arranging at least one single-loop three-dimensional open resonant unit on a corresponding target medium support structure in a target nonlinear multi-configuration mode; at least one tuning unit is used for matching the resonant frequency of the at least one single-loop three-dimensional open resonant unit and a target Larmor frequency; a passive nonlinear regulation module is used for controlling the at least one single-loop three-dimensional open resonant unit to automatically detune in a target magnetic resonance radio frequency transmission stage and automatically resonate in a target magnetic resonance radio frequency receiving stage based on the matched resonant frequency, so as to enhance the nonlinear multi-configuration magnetic resonance imaging signal-to-noise ratio of an object to be imaged in a target region. Therefore, the problems of the related art, such as the load effect causing the resonant frequency point to deviate, the poor enhancement stability, the B1 field distortion caused by the radio frequency transmission stage and the like, are solved.

The invention discloses a high-B-value diffusion fat suppression image quality improvement method and a magnetic resonance imaging system. The method comprises the following steps: designing a water excitation pulse; designing a narrow bandwidth frequency fat pressing pulse; constructing a dispersion sequence of the combined fat pressing mode; according to the method, a high B value dispersion image is obtained, most fat signals in the high B value dispersion image can be successfully inhibited by utilizing the characteristic that the water excitation pulse is insensitive to the uniformity of a B1 field, and the fat pressing effect of the dispersed high B value image in 3.0 T magnetic resonance can be improved by combining two narrow bandwidth frequency fat pressing pulses and performing supplementary inhibition on missing fat signals.

The disclosure relates to a method for operating a magnetic resonance apparatus, to a magnetic resonance apparatus, and to a computer program product. According to the method, a pre-measurement is carried out by the magnetic resonance apparatus, wherein carrying out the pre-measurement includes acquiring pre-measurement data for the object under examination. The pre-measurement data is evaluated to ascertain evaluation information. The evaluation information is used to determine whether a B1 field map needs to be measured.