Apparatus and method for characterization of a ductile membrane, surface, and sub-surface properties
Inventors
Moehring, Mark A. • Gates, George A. • Chesavage, Jay A. • Singh, Rahul
Assignees
Oto Nexus Medical Technologies Inc • Otonexus Medical Technologies Inc
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Publication Number
US-10675001-B2
Publication Date
2020-06-09
Expiration Date
Abstract
An ultrasound signal processor uses an excitation generator to cause displacement of a membrane or surface while a series of ultrasound pulses are applied to the membrane or surface. Phase differences between a transmitted signal and received signal are examined to determine the movement of the membrane or surface in response to the applied excitation. An examination of the phase response of the membrane or surface provides a determination as to whether the fluid type behind the membrane or surface is one of: no fluid, serum fluid, or purulent fluid.
Core Innovation
The patent describes a non-contact medical diagnostic system that generates a non-contact displacement force directed to an elastic surface or to a volume of material adjacent to the elastic surface. The non-contact displacement force is a step or impulse pressure, and the system transmits ultrasound energy to the elastic surface or the volume through a gas phase medium. The ultrasound transducer directs a transmit ultrasound signal to the elastic surface or the volume and receives a reflected ultrasound signal from the elastic surface or the volume.
A processor determines displacement of the elastic surface or the volume in response to the non-contact displacement force and the reflected ultrasound signal. The displacement is determined by analysis of a ringdown characteristic of tissue motion in response to the step or impulse pressure, optionally supported by phase differences and amplitude differences between transmitted and received ultrasound signals. The analysis includes phase response processing such as phase unwrapping for large phase shifts, including use of I/Q baseband channels or direct RF phase analysis.
The phase response enables determination of mechanical properties of the elastic surface or the volume, including ductility and elasticity and optionally hardness. The patent further describes material-property estimation including classification of fluid behind the membrane and extraction of fluid mechanical properties using ringdown characteristics, optionally including fluid elasticity and viscosity derived from ringdown behavior. The documented system includes an excitation generator, a gas-phase non-contact excitation/nozzle, an ultrasound transducer, transmit/receive timing, signal mixers/filters/ADC, and a phase and amplitude analyzer.
Claims Coverage
The independent claims (clm-00001, clm-00015, clm-00033, clm-00045) cover a non-contact medical diagnostic system and method in which a step or impulse non-contact displacement force is applied, ultrasound is transmitted through a gas phase medium, displacement is measured from reflected ultrasound, and a material property is calculated by analyzing a ringdown characteristic of tissue motion. Across the independent claims, the inventive features include the step/impulse non-contact force, gas-coupled ultrasound transmission and reflected-signal reception, displacement determination (including comparison of transmitted vs reflected amplitude/phase), and material-property calculation based on ringdown characteristic analysis; certain independents constrain the displacement-force frequency below 20 Hz and/or the displacement derivation and measurement mode.
Non-contact step or impulse pressure displacement force and ultrasound through gas phase coupling
An excitation generator generates a non-contact displacement force directed to an elastic surface or to a volume of material adjacent to the elastic surface, wherein the non-contact displacement force is a step or impulse pressure, and an ultrasound transducer directs a transmit ultrasound signal to the elastic surface or to the volume through a gas phase medium while receiving a reflected ultrasound signal from the elastic surface or the volume.
Displacement determination by ringdown characteristic of tissue motion
A processor determines a displacement of the elastic surface or the volume in response to the non-contact displacement force and the reflected ultrasound signal by analysis of a ringdown characteristic of a tissue motion in response to the step or impulse pressure.
Displacement measurement by comparing transmitted and reflected amplitude or phase
A method transmits ultrasound energy from a transducer to the surface or the volume adjacent to the surface through a gas phase medium and receiving a reflected ultrasound signal, comparing at least one of an amplitude or a phase of the transmitted ultrasound energy to at least one of an amplitude or a phase of the reflected ultrasound signal to form a displacement measurement, and calculating a material property from the displacement measurement in response to the non-contact displacement force and the reflected ultrasound signal by analyzing a ringdown characteristic.
Below-20-Hz non-contact displacement force for displacement measurement from reflected ultrasound
An excitation generator generates a non-contact displacement force directed to an elastic surface or to a volume of material adjacent to the elastic surface, wherein the non-contact displacement force has a frequency of below 20 Hz; an ultrasound transducer directs a transmit ultrasound signal to the elastic surface or the volume and receives a reflected ultrasound signal; and a processor determines a displacement of the elastic surface or the volume in response to the non-contact displacement force and the reflected ultrasound signal.
Across the independent claims, the core claim coverage centers on non-contact step or impulse pressure excitation applied to an elastic surface (or adjacent volume), ultrasound transmission through a gas phase medium, displacement measurement from reflected ultrasound (including transmitted vs reflected amplitude/phase comparison in one independent claim), and calculating material properties (when included) by analyzing a ringdown characteristic of tissue motion. Additional claim coverage includes a constraint on the non-contact displacement force frequency below 20 Hz for determining displacement from the reflected ultrasound signal.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Medical diagnostic system for measurement related to elastic surfaces, including an application example for eye tonometry/glaucoma-related elasticity [procedural detail omitted for safety].
Food fermentation/cure application example for completion and ripeness classification [procedural detail omitted for safety].
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