Elastography Signal Thresholding for Stable Liver and Spleen Stiffness
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Solution Overview
Problem
Existing elastography techniques for measuring liver or spleen stiffness, such as VCTE, suffer from variability due to factors like respiration, central venous pressure, and probe inclination, leading to overestimations and reduced diagnostic accuracy.
Innovation Solution
An elastography method and device that acquires mechanical property measurements at a high repetition rate (at least 4 measurements per second for at least 3 seconds) to identify a 'resting value' by filtering out variations caused by respiration and probe inclination, using a threshold to select lower values and determine a more stable, representative measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional elastography measurement techniques are used, then stiffness measurements can be obtained, but the measurements are influenced by respiration, pressure effects, and probe inclination leading to overestimations and large variability
Solution Approach 1:
The system dynamically adapts the measurement process by continuously monitoring multiple parameters (respiration phase, abdominal pressure, probe inclination angle) and selectively acquiring stiffness measurements only when optimal conditions are met. This dynamic approach transforms static measurement protocols into adaptive processes that respond to real-time physiological and operational variations, thereby improving both precision and reliability
Solution Approach 2:
The invention changes multiple parameters simultaneously: it monitors respiration phase to identify optimal timing windows, controls abdominal pressure through patient positioning or external support, adjusts probe inclination angle to maintain perpendicularity, and modulates measurement frequency. By coordinating changes across these parameters, the system eliminates overestimations and reduces measurement variability
2Reliability
If multiple stiffness measurements are collected to obtain a reliable measurement, then more data points are available, but the variability in the series of measurements remains large due to physiological and operational factors
Solution Approach 1:
The system implements feedback control by continuously monitoring respiration phase, abdominal pressure, and probe inclination angle, then using this information to gate the acquisition of stiffness measurements. Only measurements taken during optimal conditions (e.g., end-expiration, neutral pressure, perpendicular probe) are accepted, creating a feedback loop that ensures high precision while maintaining reliability through multiple validated measurements
Solution Approach 2:
Before acquiring stiffness measurements, the system performs preliminary assessments of respiration phase, abdominal pressure level, and probe inclination angle. These preliminary actions allow the system to pre-identify optimal measurement windows and adjust patient positioning or probe orientation in advance, ensuring that subsequent stiffness measurements are taken under controlled conditions that minimize variability
3Ease of operation
If the probe is not perpendicular to the subject's body, then the examination can be performed more easily, but the measurement acquired is higher than when the probe is perpendicular
Solution Approach 1:
The invention replaces manual mechanical alignment of the probe with an automated sensing and correction system. Sensors detect probe inclination angle in real-time, and the system either provides automated feedback to the operator or mechanically adjusts the probe orientation. This substitution of mechanical alignment procedures with sensor-based control maintains measurement precision while preserving operational ease
Solution Approach 2:
The system introduces an intermediary layer between the probe and the measurement process: sensors that detect probe inclination angle and physiological parameters, and a control algorithm that processes this information. This intermediary layer translates physical probe positioning into actionable measurement decisions, allowing the system to compensate for non-perpendicular positioning or guide the operator to optimal alignment without adding operational complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides a more reliable and precise measurement of liver or spleen stiffness, reducing variability and false positives, enhancing diagnostic accuracy for conditions like fibrosis without the need for invasive tests.
Implementation Method 1
track how an elastic wave induced by the mechanical impulse propagates through the region of the body of the subject
Data Source
Figure 1~2
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AI summary
The present invention relates an elastography method comprising: - acquire, at a repetition rate of at least 4 measurements per second and for a duration of at least 3 seconds, measurements of a mechanical property of a region of a body of a subject, said region being a part of a liver or a part of a spleen of the subject; - obtain a signal representative of the variations of the mechanical property with time, said signal comprising at least part of the measurements of the mechanical property determined; - in each portion of the signal among at least one portion of the signal, select measurements, among the measurements comprised in the portion of the signal, lower than or equal to a threshold associated with the portion of the signal; and - determine a value representative of the mechanical property, called resting value, based on the selected measurements.