Determining material stiffness using multiple aperture ultrasound
Inventors
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MAUI ImagingMAUI Imaging develops ultrasound-based medical imaging solutions designed to overcome the limitations of traditional ultrasound, particularly in visualizing anatomy beyond bone, air, and metal barriers. Founded in 2006, the company has pioneered Computed Echo Tomography (CET) to enable diagnostic imaging in settings where conventional CT or MRI are impractical. With over 160 patents granted and FDA clearance for its K3900 system, MAUI Imaging targets applications in trauma medicine, critical care, neurosurgery, and interventional radiology, aiming to enhance timely diagnostics and interventions in both civilian and military environments.
MAUI Imaging develops ultrasound-based medical imaging solutions designed to overcome the limitations of traditional ultrasound, particularly in visualizing anatomy beyond bone, air, and metal barriers. Founded in 2006, the company has pioneered Computed Echo Tomography (CET) to enable diagnostic imaging in settings where conventional CT or MRI are impractical. With over 160 patents granted and FDA clearance for its K3900 system, MAUI Imaging targets applications in trauma medicine, critical care, neurosurgery, and interventional radiology, aiming to enhance timely diagnostics and interventions in both civilian and military environments.
Publication Number
US-11944500-B2
Publication Date
2024-04-02
Expiration Date
Abstract
Changes in tissue stiffness have long been associated with disease. Systems and methods for determining the stiffness of tissues using ultrasonography may include a device for inducing a propagating shear wave in tissue and tracking the speed of propagation, which is directly related to tissue stiffness and density. The speed of a propagating shear wave may be detected by imaging a tissue at a high frame rate and detecting the propagating wave as a perturbance in successive image frames relative to a baseline image of the tissue in an undisturbed state. In some embodiments, sufficiently high frame rates may be achieved by using a ping-based ultrasound imaging technique in which unfocused omni-directional pings are transmitted (in an imaging plane or in a hemisphere) into a region of interest. Receiving echoes of the omnidirectional pings with multiple receive apertures allows for substantially improved lateral resolution.
Core Innovation
The invention relates to ultrasound elastography for determining a stiffness of a tissue. It forms a baseline image of a region of interest with a ping-based ultrasound imaging system and transmits an ultrasonic pulse with a shear-wave-initiating transducer to induce a propagating shear wave in the region of interest. The propagating shear wave causes speckle patterns in image frames acquired with the ping-based ultrasound imaging system.
The method captures a first image frame and a second image frame, each including a speckle pattern caused by the propagating shear wave as it moves through the region of interest. The baseline image is subtracted from each image frame to obtain first and second difference frames, so that perturbations of the propagating shear wave are represented in the difference frames as changes in speckle pattern. A difference-frame-based representation is used to determine positions of the propagating shear wave.
Using the difference frames, the method calculates a first distance between an init line of the ping-based ultrasound imaging system and the first speckle pattern in the first difference frame to determine a first position, and calculates a second distance similarly to determine a second position. From the first and second positions, the method calculates a propagation speed of the propagating shear wave in the region of interest. The propagation speed is related to stiffness such as Young’s modulus using E = 3ρc^2, with tissue density ρ.
Claims Coverage
The document includes one independent claim (clm-00001). The claim coverage centers on using baseline subtraction with ping-based shear-wave imaging to obtain difference frames, extracting shear-wave positions from speckle patterns, and computing propagation speed to determine tissue stiffness; dependent claim refinements constrain computation details and acquisition configuration.
Ping-based baseline subtraction for difference frames capturing shear-wave speckle perturbations
Forming a baseline image of a region of interest with a ping-based ultrasound imaging system; transmitting an ultrasonic pulse with a shear-wave-initiating transducer to induce a propagating shear wave; imaging the region of interest to capture a first and a second image frame including first and second speckle patterns caused by the propagating shear wave; subtracting the baseline image from the first and second image frames to obtain a first and a second difference frame.
Speckle pattern distance from init line to determine propagating shear-wave positions
Calculating a first distance between an init line of the ping-based ultrasound imaging system and the first speckle pattern of the first difference frame to determine a first position of the propagating shear wave; calculating a second distance between the init line and the second speckle pattern of the second difference frame to determine a second position.
Propagation speed from first and second shear-wave positions
Calculating a propagation speed of the propagating shear wave in the region of interest from the first and second positions in the first and second difference frames.
Across the independent claim, the key inventive elements are the ping-based formation of a baseline image, subtraction to create difference frames with speckle-pattern perturbations of the propagating shear wave, determination of shear-wave positions using distances from an init line to speckle patterns, and calculation of propagation speed from those positions; dependent claims further specify speed computation and optionally derive tissue stiffness from the measured propagation speed.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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