G01R33/4838

EXCITATION REGION SETTING METHOD AND MAGNETIC RESONANCE IMAGING APPARATUS

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.

UNGATED NON-CONTRAST ENHANCED MAGNETIC RESONANCE ANGIOGRAPHY USING MULTIPLE SUBSET RECONSTRUCTION AND TEMPORAL MAXIMUM INTENSITY PROJECTION
20210045634 · 2021-02-18 ·

A system and method for a non-contrast enhanced magnetic resonance imaging technique using a temporal maximum intensity projection reconstructed from multiple temporal subsets of data acquired the acquisition window. The method includes applying a radiofrequency pulse to the subject, waiting a quiescent interval, performing a radial acquisition with a golden-angle view angle increment over a duration corresponding to a cardiac cycle of the subject to generate acquisition data, reconstructing a plurality of images across a plurality of temporal phases from the acquisition data and generating a temporal maximum intensity projection image by tracking an intensity of each pixel across the plurality of images and selecting the pixel having a maximum intensity value across the plurality of images.

Simultaneous pH and oxygen weighted MRI contrast using multi-echo chemical exchange saturation transfer imaging (ME-CEST)

The present disclosure provides a method that includes applying at least one radiofrequency saturation pulse at a frequency or a range of frequencies to substantially saturate magnetization corresponding to an exchangeable proton in the ROI to generate magnetic resonance (MR) data. The MR data is then acquired using an echo-planar imaging readout, which is configured to sample a series of gradient echo pulse trains at a series of gradient echo times and a series of spin echo pulse trains at a series of spin echo times. One or more relaxometry measurement is then computed using the MR data sampled at the gradient echo times and the spin echo times. An oxygen-weighted image is then generated using the one or more relaxometry measurement, and a pH-weighted image is generated using MR data sampled at one or more of the spin echo times or gradient echo times.

PH-weighted MRI using fast amine chemical exchange saturation transfer (CEST) imaging

A pH-weighted chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) method and system are provided that works by indirectly measuring the NMR signal from amine protons found on the backbones of amino acids and other metabolites, which resonate at a frequency of +2.8-3.2 ppm with respect to bulk water protons. The technique uses a modified magnetization transfer radiofrequency saturation pulse for the generation of image contrast. A train of three 100 ms Gaussian pulses at high amplitude (6 uT) or Sinc3 pulses are played at a particular frequency off-resonance from bulk water prior to a fast echo planar imaging (EPI) readout, with one full image acquired at each offset frequency. This non-invasive pH-weighted MRI technique does not require exogenous contrast agents and can be used in preclinical investigations and clinical monitoring in patients with malignant glioma, stroke, and other ailments.

EMULATION MODE FOR MRI
20200408866 · 2020-12-31 ·

The invention relates to a magnetic resonance imaging system (100). The magnetic resonance imaging system (100) is configured to be selectively operated in a default mode and an emulation mode. Execution of machine executable instructions (290) by a processor (203) of the magnetic resonance imaging system (100) causes the magnetic resonance imaging system (100) to receive a selection signal selecting the emulation mode. The magnetic resonance imaging system (100) switches from the default mode to the emulation mode. The magnetic resonance imaging system (100) is operated in the emulation mode using the set of emulation control parameters (292). The emulated magnetic resonance imaging data (270) is acquired from the imaging zone (108) of the magnetic resonance imaging system (100).

SYSTEMS AND METHODS FOR BACKGROUND SUPPRESSION IN TIME-OF-FLIGHT MAGNETIC RESONANCE ANGIOGRAPHY
20200400768 · 2020-12-24 ·

Systems and methods for suppressing background in time-of-flight (TOF) magnetic resonance angiography (MRA) are disclosed. An exemplary method includes obtaining a first TOF image through a high-resolution acquisition with a saturation band on one side of an imaging slab, obtaining a second TOF image through a low-resolution acquisition with two saturation bands on both sides of the imaging slab, and subtracting the second TOF image from the first TOF image to obtaining a subtraction TOF image. Post processing such as maximum intensity projection (MIP) is performed on the subtraction TOF image.

Systems and methods for background suppression in time-of-flight magnetic resonance angiography

Systems and methods for suppressing background in time-of-flight (TOF) magnetic resonance angiography (MRA) are disclosed. An exemplary method includes obtaining a first TOF image through a high-resolution acquisition with a saturation band on one side of an imaging slab, obtaining a second TOF image through a low-resolution acquisition with two saturation bands on both sides of the imaging slab, and subtracting the second TOF image from the first TOF image to obtaining a subtraction TOF image. Post processing such as maximum intensity projection (MIP) is performed on the subtraction TOF image.

METHOD FOR PROVIDING GUIDE INFORMATION ASSOCIATED WITH ARTIFACTS AND MAGNETIC RESONANCE IMAGING DEVICE THEREFOR
20200383601 · 2020-12-10 · ·

A magnetic resonance imaging (MRI) device according to one embodiment is provided. The MRI device includes: a display configured to display a first image of an object; a controller configured to determine a signal region of the object based on the first image of the object; and a user input device configured to receive a user input of setting a region of interest (ROI) on the first image. When the set ROI is part of the signal region of the object, the controller is further configured to control the display to display guide information for preventing aliasing artifacts from occurring in a second image to be generated based on the set ROI.

Methods and systems for chemical exchange saturation transfer signal matching
10859656 · 2020-12-08 · ·

A method of determining an exchange rate between a solute material and a solvent material in chemical exchange with each other in a sample comprises performing a plurality of CEST scans on the sample to determine a reference data signal and a label data signal; simulating a plurality of CEST scans on the sample to obtain a reference dictionary signal and a plurality of label dictionary signals, each label dictionary signal corresponding to a candidate exchange rate; correcting the reference dictionary signal and each label dictionary signal for a magnetization transfer effect; determining a final data signal based on the reference data signal and the label data signal; determining a plurality of final dictionary signals based on the reference dictionary signal and the plurality of label dictionary signals; and determining the exchange rate by matching the final data signal to one of the plurality of final dictionary signals.

SHIM-DEPENDENT SPOILER GRADIENTS
20200379069 · 2020-12-03 ·

A method for determining a spoiler gradient of a magnetic resonance (MR) system is provided. At least one shim parameter that defines a shim magnetic field for compensating for B0 magnetic field inhomogeneities in a measurement volume of the MR system is received. As a function of the at least one shim parameter, at least one spoiler parameter that defines a spoiler gradient for canceling out a transverse magnetization is determined. The spoiler gradient is applied together with the shim magnetic field in a measurement of the MR system.