Diffusion Basis Spectrum Imaging for White Matter Pathology

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Solution Overview

Problem

Current diffusion tensor imaging (DTI) techniques are inadequate for accurately resolving complex white matter pathologies in the central nervous system (CNS), particularly in scenarios involving inflammation, tissue loss, and demyelination, as they fail to differentiate between acute inflammation and chronic tissue loss, and cannot correctly describe axonal fiber directions in crossing tracts or reflect the underlying pathologies in complex tissue scenarios.

Innovation Solution

The implementation of diffusion basis spectrum imaging (DBSI), which uses a multi-tensor model to quantify and differentiate various diffusion components within a tissue volume, including isotropic components, to provide accurate directional diffusivities and volume ratios, enabling the identification of distinct pathologies and the estimation of axonal regeneration and tissue damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If diffusion tensor imaging (DTI) is used to diagnose CNS white matter pathology, then the imaging capability is improved compared to other techniques, but it fails to correctly resolve complex underlying pathologies such as acute inflammation versus chronic tissue loss

Engineering Contradiction:
Improvepathology differentiation accuracyVSAvoidpathology identification reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the diffusion signal into multiple distinct components (isotropic diffusion component representing acute inflammation, chronic tissue loss, and chronic gliosis; and anisotropic diffusion component representing axonal fibers). This segmentation allows each pathology type to be independently quantified and differentiated, resolving the inability of conventional DTI to distinguish between different pathological processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces new diffusion parameters including the isotropic diffusion component (IDC), anisotropic diffusion component (ADC), axial diffusivity (λ∥), radial diffusivity (λ⊥), and volume ratios of different tissue components. These parameter changes enable more precise characterization of white matter pathology by separately measuring diffusion properties in different directions and components, thereby improving both measurement precision and reliability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional DTI techniques are used, then the imaging process is simple, but it cannot differentiate between acute inflammation and chronic tissue loss in complex tissue scenarios

Engineering Contradiction:
Improveimaging technique complexityVSAvoidpathology differentiation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the diffusion signal into multiple pathology-specific components (isotropic and anisotropic) that can be independently analyzed. This allows the imaging technique to maintain a relatively simple overall framework while achieving high measurement precision through component separation and independent quantification of each pathology type.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If invasive CNS biopsies are performed to obtain histological specimens, then diagnostic accuracy is improved, but patient injury risk increases

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidpatient injury
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent creates a noninvasive copy of histological information through diffusion MRI imaging. By quantifying diffusion parameters (IDC, ADC, λ∥, λ⊥) that correspond to specific pathological features, the imaging technique produces a virtual histological map that accurately reflects tissue pathology without requiring physical tissue sampling, thereby eliminating patient injury while maintaining diagnostic accuracy.

Inventive Principle:
Principle #26Copying

4Loss of information

If autopsy tissues are used to study CNS pathology, then important pathological insights are obtained, but long postmortem delay artifacts cause tissue degradation

Engineering Contradiction:
Improvepathological informationVSAvoidpostmortem delay
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent performs preliminary action by conducting noninvasive diffusion MRI imaging during the patient's lifetime to capture pathological information before death and tissue degradation occur. By measuring diffusion parameters in vivo, the technique preserves accurate pathological information without the time loss and artifacts associated with postmortem autopsy, enabling longitudinal monitoring of disease progression and treatment response.

Inventive Principle:
Principle #10Preliminary action

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

DBSI effectively differentiates acute inflammation from chronic tissue loss, estimates axonal regeneration, and accurately reflects the progression of CNS pathologies, offering improved diagnostic capabilities compared to traditional DTI methods, and can be used in clinical settings to assess treatment efficacy and disease progression.

Implementation Method 1

diffusion magnetic resonance data representing a volume of the tissue... diffusion of water in the direction of the probable fiber and a radial diffusivity indicating a diffusion of water perpendicular to the direction of the probable fiber

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS9494669B2Diagnosis of central nervous system white matter pathology using diffusion MRI
Publication Date: 2016.11.15 WASHINGTON UNIV IN SAINT LOUIS
  • US9494669B2 patent drawing
  • US9494669B2 patent drawing
  • US9494669B2 patent drawing

AI summary

Determining diffusivity of multiple diffusion components within a tissue using diffusion magnetic resonance data representing a volume of the tissue. A plurality of candidate fibers having a direction is defined within the volume. A possibility coefficient is calculated by a processor for each candidate fiber of the plurality of candidate fibers based on the magnetic resonance data and the direction of the candidate fiber. The possibility coefficient represents a likelihood that the candidate fiber exists in the volume. Candidate fibers associated with a possibility coefficient greater than a threshold value are selected by the processor to create one or more probable fibers. For each probable fiber of the one or more probable fibers, an axial diffusivity indicating a diffusion of water in the direction of the probable fiber and a radial diffusivity indicating a diffusion of water perpendicular to the direction of the probable fiber are calculated by the processor. The diffusivity of isotropic diffusion component and the volume ratios of each fiber component and isotropic components are calculated.