Epileptic Focus Localization via Baseline-Ictal Image Subtraction

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Solution Overview

Problem

Current methods for localizing epileptic foci in neuroimaging, such as SISCOM and SPM, often produce difference images with numerous irrelevant high-variation areas, making interpretation challenging due to the identification of too many potential focus regions.

Innovation Solution

A method that aligns and normalizes baseline and ictal images to produce a difference image, then selects and propagates regions of interest, eliminating those without local maxima in the corresponding image, thereby reducing distracting information and confirming clinically significant focus regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If classical SISCOM method is used to produce difference images, then epileptic focus localization is facilitated, but too many potential focus areas are identified making interpretation difficult

Engineering Contradiction:
Improvedifficulty of interpreting difference imagesVSAvoidnumber of relevant focus areas identified
Core Design Contradiction:
Difficulty of detecting and measuringVSLoss of information

Solution Approach 1:

The patent extracts only the most significant features from the difference image by propagating regions of interest to the baseline image and retaining only those with local maxima. This selective extraction removes irrelevant high-variation areas while preserving clinically significant focus regions, directly resolving the contradiction between facilitating interpretation and maintaining relevant information.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different processing criteria to different regions of the image. Regions of interest are propagated to the baseline image and evaluated based on local maximum characteristics. This local quality approach ensures that only regions with genuine focal abnormalities (local maxima in baseline) are retained, while other areas are filtered out, thus improving interpretability without losing relevant focus areas.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If thresholding is applied to normalized difference image, then potential foci are visualized, but the number of candidate regions increases making analysis more complex

Engineering Contradiction:
Improveprecision of focus identificationVSAvoidcomplexity of image analysis
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary processing by propagating regions of interest to the baseline image before final thresholding and visualization. This preliminary action pre-filters the candidate regions based on their presence as local maxima in the baseline, reducing the number of candidates that require detailed analysis and thereby simplifying the overall analysis complexity while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs a dynamic, multi-stage filtering process where regions are progressively evaluated and filtered. Rather than applying a single static threshold, the method dynamically adjusts the candidate set through propagation to baseline image and local maximum detection, adapting the analysis complexity to the actual data characteristics while preserving measurement precision.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS9171366B2Method for localization of an epileptic focus in neuroimaging
Publication Date: 2015.10.27 SIEMENS MEDICAL SOLUTIONS USA INC
  • US9171366B2 patent drawing
  • US9171366B2 patent drawing

AI summary

In a method for localizing a candidate foci in neuroimaging, two images are acquired, one being a baseline (interictal) image and another being an intervention (ictal) image. The two images are aligned and the intensities of the images are normalized. A difference image is calculated by subtracting the baseline (interictal) image from the intervention (ictal) image. The difference image is normalized and regions of interest are selected as candidate foci.