MR Tissue Differentiation via Phase Encoding
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Solution Overview
Problem
Conventional magnetic resonance tomography methods struggle to differentiate among silicon-dominated, water-dominated, and fat-dominated tissues effectively, particularly in applications involving silicon implants or reconstructive plastic surgery, where a fast and high-resolution imaging technique is needed to depict individual components accurately.
Innovation Solution
A method and system that acquire two magnetic resonance signals per pixel, with specific phase conditions to distinguish between silicon, water, and fat tissues, allowing for automatic differentiation and generation of separate images for each tissue type, using a magnetic resonance system with a control unit and evaluation device to determine pixel associations based on phase information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional two-point Dixon techniques are used to differentiate water and fat tissues, then water and fat tissue differentiation is achieved, but silicon-dominated material cannot be differentiated
Solution Approach 1:
The patent segments the tissue differentiation task into three distinct classification problems by acquiring three separate magnetic resonance signals with different phase encoding conditions. Each signal targets a specific tissue type (water, fat, or silicon) by exploiting their unique phase characteristics at different echo times, allowing independent differentiation of each tissue type without interference from the others.
2Measurement precision
If more magnetic resonance signals are acquired per pixel to differentiate three tissue types, then differentiation accuracy improves, but acquisition time increases
Solution Approach 1:
The patent changes the phase encoding parameters of the magnetic resonance signals at different echo times to create distinct phase relationships for different tissue types. By carefully selecting echo times where water, fat, and silicon exhibit characteristic phase differences (water and fat in-phase at one echo time, out-of-phase at another; silicon always out-of-phase with water), the method achieves three-tissue differentiation using only two additional signals beyond a standard sequence, optimizing the precision-time tradeoff.
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
Enables the creation of separate MR images showing each tissue type from two acquired images, improving diagnostic capabilities in medical imaging by accurately differentiating and quantifying silicon, water, and fat components, even in complex tissue environments like silicon implants.
Implementation Method 1
In the case of tissue types that have respectively different chemical shifts, a different magnetic field results at the nucleus which leads to different resonance frequencies. In signal acquisition this leads to different phase angles of the two components.
Implementation Method 2
Separation of the signals of two different tissue types (for example fat and water) can be done by utilization of the phase information of acquired MR signals.
Data Source
AI summary
In a magnetic resonance method and device for automatic differentiation of respective pixels as representing either a silicon-dominated substance, or fat-dominated tissue, or water-dominated tissue, a first magnetic resonance signal and a second magnetic resonance signal are acquired per pixel, wherein the first magnetic resonance signal per pixel is acquired at a point in time at which the phase of a magnetic resonance signal originating from water-containing tissue exhibits a phase opposite to the phase of a magnetic resonance signal originating from fat-containing tissue, and the second magnetic resonance signal is acquired per pixel at a point in time at which the phase of the magnetic resonance signal originating from water-containing tissue exhibits a phase identical to the phase of the magnetic resonance signal originating from fat-containing tissue, and the phase of a magnetic resonance signal originating from a silicon-containing substance exhibits a phase opposite to the phase of the magnetic resonance signal originating from water-containing or fat-containing tissue. A first intermediate result is determined that indicates whether the pixel represents water-dominated tissue or fat-dominated tissue on the basis of first magnetic resonance signals. A second intermediate result is determined that indicates whether the pixel represents the silicon-dominated substance on the basis of second magnetic resonance signals. The pixel is designated as representing water-dominated tissue, fat-dominated tissue or the silicon-dominated substance on the basis of the first intermediate result and the second intermediate result.