ARFI Displacement Imaging Using Adaptive Time Instance Selection

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Solution Overview

Problem

Acoustic radiation force impulse (ARFI) imaging is biased by maximum tissue displacement, leading to errors in tissue elastic property determination due to accumulation of displacements over time, which affects diagnostic accuracy.

Innovation Solution

A cost function is used to identify the optimal time for tissue displacement measurement, considering contrast and signal-to-noise ratio, to generate an ARFI image that is less reliant on maximum displacement, thereby providing more accurate tissue elasticity information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If maximum displacement is used to generate ARFI images, then the imaging process is simple, but measurement precision deteriorates due to bias from displacement accumulation

Engineering Contradiction:
Improveimaging process simplicityVSAvoidtissue elastic property measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by transitioning from a static maximum displacement measurement to a dynamic time-dependent displacement measurement. The system measures displacement at multiple time points after ARFI application and selects the optimal time point based on cost function evaluation, allowing the measurement to adapt to the transient response characteristics of the tissue rather than relying on a fixed maximum value.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the measurement parameter from maximum displacement magnitude to displacement at a specifically selected time point. The cost function evaluates multiple parameters including contrast, signal-to-noise ratio, and temporal characteristics to identify the optimal time point, thereby changing the measurement approach to eliminate bias from displacement accumulation while maintaining imaging simplicity.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If displacement accumulation over time is allowed, then the transient response is captured completely, but measurement precision deteriorates due to biased maximum displacement values

Engineering Contradiction:
Improvetransient response durationVSAvoidmaximum displacement accuracy
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by measuring displacement at multiple time points during the transient response and evaluating them using a cost function before finalizing the measurement. This preliminary evaluation allows the system to identify the optimal time point that avoids the bias of maximum displacement while capturing the essential tissue elastic properties, effectively preparing the measurement in advance to ensure accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through the cost function evaluation process, where the measured displacement data at different time points is systematically evaluated and compared. The feedback mechanism selects the optimal time point based on multiple criteria including contrast and signal-to-noise ratio, allowing the system to learn from the transient response characteristics and make an informed selection that eliminates measurement bias.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If time-dependent displacement measurement is implemented, then measurement precision improves, but device complexity increases due to multiple time point measurements

Engineering Contradiction:
Improvetissue elastic property measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by using a single cost function framework that can evaluate multiple time points and select the optimal one for various tissue types and imaging conditions. The cost function integrates multiple criteria (contrast, signal-to-noise ratio, temporal characteristics) into a unified evaluation mechanism, allowing the same system to handle different scenarios without requiring separate complex processing paths for each case.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements self-service through the automated cost function evaluation process, where the system independently analyzes the displacement data at different time points and selects the optimal measurement time without requiring external intervention. The cost function automatically balances the trade-off between capturing transient response characteristics and avoiding measurement bias, reducing the need for manual configuration or complex user input.

Inventive Principle:
Principle #25Self-service

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

This approach allows for the generation of ARFI images that better represent tissue elasticity, reducing diagnostic errors by selecting the appropriate time instance for displacement measurement, which enhances image quality and border definition.

Implementation Method 1

acoustic radiation force impulse (ARFI) imaging... a shear, longitudinal or other wave is generated with an ARFI transmitted as a push pulse. Ultrasound energy is transmitted to a focal region to generate the wave, resulting in displacement of tissue around the focal region

Methodology Applied
Scientific EffectAcoustic radiation force: Acoustic Radiation Pressure

Implementation Method 2

Further ultrasound scanning tracks the displacement of tissue over time at locations around the focal region. For each location, the peak or maximum displacement is determined

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS9332962B2Ultrasound ARFI displacement imaging using an adaptive time instance
Publication Date: 2016.05.10 SIEMENS MEDICAL SOLUTIONS USA INC
  • US9332962B2 patent drawing
  • US9332962B2 patent drawing
  • US9332962B2 patent drawing

AI summary

In ARFI imaging, a cost function is used to identify a time of displacement that best or sufficiently indicates the desired information. For example, the displacements associated with a combination of contrast and signal-to-noise ratio are identified. The time at which the desired displacements occur may be other than the time of the maximum. Since the time is common to displacements for one or more scan lines, the displacement image may be assembled line-by-line or by groups of lines.