Multi-View Polyp Matching via Local Appearance Features

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Solution Overview

Problem

Current systems for detecting polyps in medical images, particularly in Computed Tomography Colonography (CTC), face challenges in achieving high sensitivity while minimizing false positives, especially when dealing with collapsed or deformed colon segments, and require manual registration which is time-consuming and inaccurate.

Innovation Solution

A processor-based system that performs multi-view matching of regions of interest using local appearance features, learns a distance metric through feature selection and metric boosting, allowing for efficient matching of polyps across prone and supine views without the need for global geometric information or surface registration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual registration of polyp findings or colon segments is performed, then accuracy can be assessed, but it is time-consuming and difficult

Engineering Contradiction:
Improveaccuracy of polyp finding assessmentVSAvoidtime required for registration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical registration processes with an automated computational system that uses feature extraction and matching algorithms. The system automatically registers colon segments across multiple views by extracting local features (shape, texture, intensity) and matching them through computational methods, eliminating the need for manual radiologist registration while achieving comparable or superior accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-registration by automatically aligning colon segments across different views without requiring external manual intervention. The automated algorithm independently extracts features, computes transformations, and registers segments, allowing the system to serve itself rather than requiring continuous manual guidance for registration tasks.

Inventive Principle:
Principle #25Self-service

2Reliability

If current CAD systems detect polyps with high sensitivity, then detection rate improves, but false positives increase

Engineering Contradiction:
Improvesensitivity of polyp detectionVSAvoidfalse positive rate
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by analyzing local appearance features (shape, texture, intensity characteristics) of specific colon segments rather than relying solely on global detection algorithms. This localized analysis allows the system to distinguish true polyps from false positives by examining the unique local characteristics of each segment, improving both sensitivity and specificity simultaneously.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system segments the colon into multiple segments across different views (prone, supine, lateral) and analyzes each segment independently. By dividing the complex detection task into smaller segment-level analyses, the system can apply specialized feature extraction and matching to each segment, reducing false positives while maintaining high sensitivity through comprehensive coverage.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If multi-view matching is performed to assess polyp mobility, then detection accuracy improves, but system complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the multi-view matching task into independent module: feature extraction module, feature matching module, and registration module. Each module processes specific aspects of the data independently, making the overall complex system manageable through modular architecture. The system processes prone, supine, and lateral views as separate but coordinated components, reducing computational complexity while maintaining comprehensive analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system manages complexity by dynamically adjusting parameter thresholds and feature weights based on the specific viewing conditions and colon segment characteristics. Rather than using fixed complex parameters, the system adapts feature extraction and matching parameters to the local context, simplifying the overall system while improving detection accuracy across different views.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8885898B2Matching of regions of interest across multiple views
Publication Date: 2014.11.11 SIEMENS HEALTHCARE GMBH
  • US8885898B2 patent drawing
  • US8885898B2 patent drawing
  • US8885898B2 patent drawing

AI summary

Described herein is a framework for multi-view matching of regions of interest in images. According to one aspect, a processor receives first and second digitized images, as well as at least one CAD finding corresponding to a detected region of interest in the first image. The processor determines at least one candidate location in the second image that matches the CAD finding in the first image. The matching is performed based on local appearance features extracted for the CAD finding and the candidate location. In accordance with another aspect, the processor receives digitized training images representative of at least first and second views of one or more regions of interest. Feature selection is performed based on the training images to select a subset of relevant local appearance features to represent instances in the first and second views. A distance metric is then learned based on the subset of local appearance features. The distance metric may be used to perform matching of the regions of interest.