The present disclosure relates to a system and method for non-invasively determining NAFLD activity scores (NAS) in patients using mechanical properties determined through magnetic resonance elastography (MRE) imaging. The non-invasively determined NAS score is then used to diagnose NFALD and NASH patients.

A Magnetic Resonance Imaging apparatus according to an embodiment includes processing circuitry. The processing circuitry is configured to obtain a plurality of diffusion weighted images including a plurality of first diffusion weighted images taken while a first Motion Probing Gradient (MPG) is applied in a plurality of directions and a plurality of second diffusion weighted images taken while a second MPG having a b value of a different magnitude from that of a b value calculated for the first MPG is applied in the plurality of directions. The processing circuitry is configured to calculate an elastic modulus of a biological tissue with respect to each of a plurality of directions, on the basis of the plurality of diffusion weighted images.

A method for reconstructing displacement and strain maps of human tissue of a subject in vivo or other objects includes applying a mechanical deformation for a target area, imaging tissues while deformation is applied on the target area, measuring the axial and lateral displacements and axial, lateral, and shear strains of tissue in the target area, differentiating between tissues of different stiffness and strain responses, and labeling tissues of different stiffness and strain responses. In some embodiments, displacement and strain imaging are performed using a high-resolution, high-speed, highly-accuracy hierarchy recursive displacement tracking from conventional ultrasound brightness mode images. Particularly, this invention relates to the reconstruction of displacement and strain images from conventional ultrasound B-mode images acquired using any ultrasound machine of different manufacturers without the need to use carrier signals.

A system that determines an invariant magnetic-resonance (MR) signature of a biological sample is disclosed. During operation, the system determines a magnetic-resonance (MR) model of voxels in a biological sample based on differences between MR signals associated with the voxels in multiple scans and simulated MR signals. The MR signals are measured or captured by an MR scanner in the system during multiple MR scans, and based on scanning instructions, and the simulated MR signals for the biological sample are generated using the MR model and the scanning instructions. Moreover, the system iteratively modifies the scanning instructions (including a magnetic-field strength and/or a pulse sequence) in the MR scans based on the differences until a convergence criterion is achieved. Then, the system stores, in memory, an identifier of the biological sample and a magnetic-field-strength-invariant MR signature of the biological sample that is associated with the MR model.

A method and system provides an acquisition scheme for generating magnetic resonance elastography displacement data with whole-sample coverage, high spatial resolution, and adequate SNR in a short scan time. The method and system can acquire in-plane and through-plane k-space shots over a volume of a sample divided into a plurality of slabs that each include a plurality of non-adjacent slices to obtain three dimensional multiband, multishot data, can apply multiband radio frequency refocusing pulses to the sample, can acquire navigators before readout, and can correct for non-linear motion errors.

Methods and system for characterizing ligament properties using elastography are disclosed. An ultrasound system capable of performing shear wave elasticity imaging and/or supersonic shear imaging may retrieve one or more images from a proposed surgical site. The one or more images may be provided to a surgical planning system that identifies one or more properties of ligaments proximate to the surgical site. Musculoskeletal simulations may be performed using the identified properties to preoperatively identify a surgical plan. Preoperative identification of a surgical plan may enable a surgeon to select from more fine-tuning options for a joint replacement than conventional systems.

Magnetic resonance and ultrasound methods can produce estimates of full rank-4 elasticity tensors (E-tensors) using suitable constraints. E-tensor estimates can be based on E-tensor symmetry conditions and a suitable E-tensor selected from among a set of E-tensors calculated using different symmetry constraints. Displacement fields used in E-tensor calculations can be noise reduced using compatibility conditions. With the selected E-tensor, various stains that are rotation invariant can be computed. In one example. an E-tensor for an in vivo brain is computed using the mechanical disturbance associated with cardiac pulsations. The selected E-tensor and associated stains. physiological disorders such as Alzheimer's disease and traumatic brain injury (TBI) and even neural activation may be more readily detected than with conventional methods that do not use the full E-tensor.

The invention provides for a medical instrument (200, 400, 500) comprising a magnetic resonance imaging system (202), a transducer (222) for mechanically vibrating at least a portion of the subject within the imaging zone. Instructions cause a processor (236) controlling the medical instrument to: control (100) the transducer to vibrate; control (102) the magnetic resonance imaging system to repeatedly acquire the magnetic resonance data (252) using a first spatially encoding pulse sequence (250); control (104) the magnetic resonance imaging system to acquire navigator data (256) using a second spatially encoding pulse sequence (254); construct (106) a set of navigator profiles (258, 804, 904, 1004, 1108, 1208, 1308) using the navigator data; determine (108) at least one parameter (260) descriptive of transducer vibrations using the set of navigator profiles; and reconstruct (110) at least one magnetic resonance rheology image (262) from the magnetic resonance data.

A method for determining a signature index of an observed tissue comprises the step of providing a generic attenuation model of a motion-probing gradient pulse MRI attenuated signal S(b), and providing a reference model parameter vector (p.sub.R(i)) corresponding to a reference state of the tissue. On the basis of the evolution of the determined partial differential sensitivities dS.sub.i(b) of the model attenuated signal S(b) to each model parameter p(i) at the neutral state attenuated signal S.sub.N(b) versus b values, a discrete and narrow size set of key b is built and a series of MRI images of the observed tissue are acquired by using the key b values. Then, for each voxel a signature index (sADC(V), Sdist(V), SCdist(V), Snl(V), SI(V)) of the voxel V is determined as a scalar function depending on a distance between the voxel signal pattern acquired at the key b values and the signal pattern of the reference state of the tissue at the same key b values. An apparatus is configured for implementing such a method.

A magnetic resonance examination system in which the patient carrier is mounted moveably in a direction transverse to the support surface and an RF antenna having a fixed geometrical relation to the support surface.