Pulmonary Nodule Detection Using Hierarchical Vector Quantization

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Solution Overview

Problem

Conventional methods for detecting pulmonary nodules in CT images face challenges in differentiating between malignant and benign nodules, particularly due to the high volume of data radiologists must analyze and the difficulty of accurately segmenting nodule surfaces, which delays potential cancer treatment.

Innovation Solution

The method employs hierarchical vector quantization to expand 2D feature models into 3D models, using textural features and principal component analysis to improve classification performance between benign and malignant nodules, with 2D texture features calculated from 3D volumetric data to enhance detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional virtual biopsy methods are used to differentiate malignant and benign nodules, then differentiation capability is provided, but the process is delayed due to high volume of CT data requiring manual review

Engineering Contradiction:
Improvedifferentiation capabilityVSAvoidevaluation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual radiologist review with an automated computer-aided detection system that uses hierarchical vector quantization and textural feature analysis to differentiate malignant and benign nodules, eliminating the time-consuming manual evaluation process while maintaining diagnostic accuracy

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

Solution Approach 2:

The system transforms the evaluation process by changing from manual visual inspection to automated computational analysis using hierarchical vector quantization algorithms and textural features extracted from 3D volumetric data, fundamentally altering how nodule differentiation is performed

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If 2D texture features are calculated from single slice data, then calculation simplicity is maintained, but detection accuracy is reduced

Engineering Contradiction:
Improvecalculation simplicityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from analyzing 2D single slice images to extracting textural features from 3D volumetric data, adding a third dimension to the analysis. This enables calculation of 2D texture features that incorporate depth information from multiple slices, significantly improving detection accuracy while maintaining the simplicity of 2D feature calculation methods

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system nests 2D texture feature calculation within 3D volumetric analysis, where 2D features are computed from multiple nested slices that together form the 3D nodule volume. This allows simple 2D calculation methods to benefit from complex 3D structural information

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If shape description and growth evaluation methods are used for nodule classification, then tumor classification capability is provided, but segmentation accuracy requirements increase system complexity

Engineering Contradiction:
Improvetumor classification capabilityVSAvoidsegmentation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts textural features directly from 3D volumetric data without requiring precise nodule segmentation. By focusing on texture patterns rather than boundary definitions, the system obtains tumor classification capability while avoiding the complexity of accurate segmentation algorithms

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9639933B2Method for adaptive computer-aided detection of pulmonary nodules in thoracic computed tomography images using hierarchical vector quantization and apparatus for same
Publication Date: 2017.05.02 THE RES FOUNDATION FOR THE STATE UNIV OF NEW YORK
  • US9639933B2 patent drawing
  • US9639933B2 patent drawing
  • US9639933B2 patent drawing

AI summary

Provided are an apparatus and method for fast and adaptive computer-aided detection of pulmonary nodules and differentiation of malignancy from benignancy in thoracic CT images using a hierarchical vector quantization scheme. Anomalous pulmonary nodules are detected by obtaining a two-dimensional (2D) feature model of a pulmonary nodule, segmenting the pulmonary nodule by performing vector quantification to expand the 2D feature model to a three-dimensional (3D) model, and displaying image information representing whether the pulmonary nodule is benign, based upon the 3D model expanded from the 2D feature model, with duplicate information eliminated by performing feature reduction performed using a principal component analysis and a receiver operating characteristics area under the curve merit analysis. A textural feature analysis detects an anomalous pulmonary nodule, and 2D texture features are calculated from 3D volumetric data to provide improved gain compared to calculation from a single slice of 3D data.