Nowadays, the interest to use mechanical waves in various field such medical field or geophysical field is well established. Indeed, the study of mechanical waves propagating in a medium allows usually to retrieve the properties of this medium. In solid media, a mechanical wave is composed of two components: a compression wave and a shear wave. Depending on the field of application, it may be preferable to characterize only one of the components. However, the discretization of each component of the mechanical waves may be difficult and conventional methods are not necessarily suitable for some media. The present disclosure overcomes the above drawback by proposing a new method for separating a displacement vector field U resulting from the displacement of a mechanical wave in a medium into its shear component and its compression component. Such method is particularly adapted when the components of the mechanical waves propagate with similar speed in the medium, for instance a shear wave and a slow Biot wave in a poroelastic medium.

Described here are systems and methods for a robust magnetic resonance elastography (MRE) imaging platform for rapid dynamic 3D MRE imaging. The imaging platform includes an MRE pulse sequence and advanced image reconstruction framework that work synergistically in order to greatly expand the domains where MRE can be deployed successfully.

A coil pad according to one embodiment is a coil pad that is placed between a receiving coil and a subject. The receiving coil is mounted on the subject and receives a magnetic resonance signal emitted from the subject. The coil pad includes a pad opening and a vibrating portion. The pad opening is aligned with a coil opening included in the receiving coil and forms a through-hole between the coil opening and the subject. The vibrating portion vibrates with a medium that transmits vibration being filled therein.

A phantom for magnetic resonance elastography (MRE) is provided. In particular, systems and methods for a phantom that is capable of generating a wave-like pattern in MRE images where a wavelength of the generated wave-like pattern is controlled by the phantom geometry. The geometrically controlled wavelength enables the phantom to calibrate MRE image acquisition and mechanical property calculation.

A coil pad according to one embodiment is a coil pad that is placed between a receiving coil and a subject. The receiving coil is mounted on the subject and receives a magnetic resonance signal emitted from the subject. The coil pad includes a pad opening and a vibrating portion. The pad opening is aligned with a coil opening included in the receiving coil and forms a through-hole between the coil opening and the subject. The vibrating portion vibrates with a medium that transmits vibration being filled therein.

The present invention provides a rheology system (202) comprising a rheology transducer device (204) for introducing mechanical waves into a subject of interest (120), whereby the rheology transducer device (204) comprises multiple transducers (212), a driving device (206) for driving the rheology transducer device (204), a sensor device (208) for sensing mechanical waves at the subject of interest (120), and a control device (210) for receiving input from the sensor device (208) and for controlling the driving device (206) based on the received input from the sensor device (208). The present invention further provides a MR rheology system (200) comprising a MR imaging system (110), and the above rheology system (202), whereby the MR imaging system (110) is adapted to control the rheology system (200). Still further, the present invention provides a rheology method comprising the steps of providing a rheology system (202) with its rheology transducer device (204) and its sensor device (208) in contact to a subject of interest (120), driving the rheology transducer device (204) to introduce mechanical waves into the subject of interest (120), sensing mechanical waves at the subject of interest (120) using the sensor device (208), and performing feedback control for driving the rheology transducer device (204) based on the mechanical waves sensed using the sensor device (208). The invention also provides MR rheology method based on the above rheology method with and without real-time feedback control.

A method for performing multi-slice MR Elastography on an anatomical region of interest associated with a patient includes inducing shear waves at a shear wave frequency value (e.g., between 25-500 Hz) in the anatomical region of interest using an external driver. Next, the anatomical region of interest is imaged during a single patient breath-hold using an MRI acquisition process. Following the MRI acquisition process(es), phase images of the anatomical region of interest are generated based on an acquired RF signal. These phase images may then be processed (e.g., using an inversion algorithm) to generate one or more quantitative images depicting stiffness of the anatomical region of interest. In some embodiments, a wave image is also generated showing propagation of the plurality of shear waves through the anatomical region of interest based on the phase images.

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.

A method for magnetic resonance elastography (MRE) is described, in which an MRE inversion that accounts for waves propagating in a finite, bounded media is employed. A vibratory motion is induced in a subject and MRE is performed to measure one or more components of the resulting displacement produced in the subject. This displacement data is subsequently filtered to provide a more accurate and computationally efficient method of inversion. Wave equations based on the geometry of the bounded media are then utilized to calculate the material properties of the subject. Such a method allows for the performance of MRE on tissues such as the heart, eye, bladder, and prostate with more accurate results.

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.