Abstract: A method for mapping shear wave velocity in biological tissues includes using an ultrasound transducer to generate mechanical excitations at a plurality of locations in a region of interest. An MRI system is used to capture a phase image of each mechanical excitation, wherein motion encoding gradients (MEGs) of the MRI system encode a propagating shear wavefront caused by the mechanical excitation. A plurality of shear wave velocity maps is generated based on the phase images, wherein each shear wave velocity map depicts velocity between adjacent propagating shear wavefronts. The shear wave speed values are combined to generate a composite shear wave velocity map of the region of interest.

Abstract: A method, system and article of manufacture is disclosed. The method includes providing a spatial navigator outside of a thermal therapy region; receiving a plurality of analog-to-digital conversion (ADC) readouts from an MRI device at a plurality of time points, wherein the ADC readouts comprise a first ADC readout acquired at a first time point, and one or more additional ADC readouts acquired at subsequent time points; processing the ADC readouts to obtain a frequency of the spatial navigator at each of the time points; obtaining a main magnetic field (B0) drift of the MRI device based on the frequency of the spatial navigator at a particular time point and the frequency of the spatial navigator at the first time point; and obtaining the temperature change at the particular time point based on the B0 drift.

Abstract: An MRI system uses a Cartesian-radial hybrid k-space trajectory to capture three-dimensional k-space data and reconstruct an image of an area of interest of a subject. The MRI system performs a series of k-space acquisitions to collect the data. A first k-space acquisition includes acquiring a two-dimensional EPI projection in a first plane parallel to a frequency-encoding direction and acquiring additional two-dimensional EPI projections in planes that are radially shifted about a center axis parallel to the frequency-encoding direction with respect to the first plane, until a selected number of projections are acquired. Each subsequent k-space acquisition includes acquiring an additional set of two-dimensional EPI projections in all of the planes in which an EPI projection was acquired during the first k-space acquisition, each additional set of EPI projections being shifted along a respective plane in a direction perpendicular to the frequency-encoding direction.

Abstract: A method for performing magnetic resonance-guided thermal therapy includes selecting a first set of sampling characteristics for acquiring a first set of slabs covering a first anatomical region of interest. Additionally, a second set of sampling characteristics is selected for acquiring a second set of slabs covering a second anatomical region of interest. This second set of sampling characteristics is distinct from the first set of sampling characteristics. An interleaved acquisition of the first set of slabs and the second set of slabs may then be performed using the first set of sampling characteristics and the second set of sampling characteristics.

Abstract: A method, system and article of manufacture is disclosed. The method includes providing a spatial navigator outside of a thermal therapy region; receiving a plurality of analog-to-digital conversion (ADC) readouts from an MRI device at a plurality of time points, wherein the ADC readouts comprise a first ADC readout acquired at a first time point, and one or more additional ADC readouts acquired at subsequent time points; processing the ADC readouts to obtain a frequency of the spatial navigator at each of the time points; obtaining a main magnetic field (B0) drift of the MRI device based on the frequency of the spatial navigator at a particular time point and the frequency of the spatial navigator at the first time point; and obtaining the temperature change at the particular time point based on the B0 drift.

Abstract: An MRI system uses a Cartesian-radial hybrid k-space trajectory to capture three-dimensional k-space data and reconstruct an image of an area of interest of a subject. The MRI system performs a series of k-space acquisitions to collect the data. A first k-space acquisition includes acquiring a two-dimensional EPI projection in a first plane parallel to a frequency-encoding direction and acquiring additional two-dimensional EPI projections in planes that are radially shifted about a center axis parallel to the frequency-encoding direction with respect to the first plane, until a selected number of projections are acquired. Each subsequent k-space acquisition includes acquiring an additional set of two-dimensional EPI projections in all of the planes in which an EPI projection was acquired during the first k-space acquisition, each additional set of EPI projections being shifted along a respective plane in a direction perpendicular to the frequency-encoding direction.

Abstract: A method for mapping shear wave velocity in biological tissues includes using an ultrasound transducer to generate mechanical excitations at a plurality of locations in a region of interest. An MRI system is used to capture a phase image of each mechanical excitation, wherein motion encoding gradients (MEGs) of the MRI system encode a propagating shear wavefront caused by the mechanical excitation. A plurality of shear wave velocity maps is generated based on the phase images, wherein each shear wave velocity map depicts velocity between adjacent propagating shear wavefronts. The shear wave speed values are combined to generate a composite shear wave velocity map of the region of interest.