CGH Data Noise Scoring for Chromosomal Abnormality Detection

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Solution Overview

Problem

Current methods for analyzing comparative genomic hybridization (CGH) data, particularly microarray-based CGH data, face challenges in accurately identifying chromosomal abnormalities due to high noise levels, which obscure underlying trends and patterns, making it difficult to detect amplifications and deletions with precision.

Innovation Solution

The implementation of global noise-based scoring methods that account for both local and global noise components in CGH data analysis, allowing for the identification of sets of contiguous chromosomal DNA subsequences that are amplified or deleted by employing a combined noise factor, thereby enhancing the detection of chromosomal abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional CGH data analysis methods are used, then the analysis process is simple, but the measurement precision of chromosomal abnormalities is poor due to high noise levels

Engineering Contradiction:
Improveprecision in identifying chromosomal abnormalitiesVSAvoidcomplexity of noise-based scoring methods
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the noise analysis into two distinct components: local noise (probe-to-probe variation) and global noise (overall data variation). This segmentation allows each noise type to be modeled and corrected independently, improving measurement precision without overwhelming complexity. The local noise is calculated from adjacent probe ratios while global noise is derived from the entire dataset distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary statistical model that mediates between the raw CGH data and the final abnormality identification. This intermediary layer computes corrected probe ratios by accounting for both local and global noise components, serving as a bridge that transforms noisy raw data into reliable diagnostic information while managing computational complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If noise-based scoring methods are implemented, then the reliability of aberration calling is improved, but the difficulty of detecting and measuring increases due to combined noise factor calculations

Engineering Contradiction:
Improvereliability of aberration callingVSAvoiddifficulty in detecting chromosomal abnormalities
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent transforms the detection approach by changing the parameters used for abnormality detection. Instead of using raw probe ratios directly, it computes corrected ratios that incorporate noise parameters (local and global variance). This parameter transformation improves reliability by accounting for noise, while the systematic approach to parameter calculation manages the complexity of detection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the calculated noise parameters are used to adjust and correct the probe ratio measurements. The local and global noise estimates feed back into the calculation of corrected ratios, continuously improving the reliability of aberration calling by compensating for identified noise sources in the data.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If global noise-based scoring is used, then the quantitative precision is increased, but the loss of information increases due to complex noise modeling

Engineering Contradiction:
Improvequantitative precision in identificationVSAvoidinformation loss in noise correction
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies partial correction by focusing on the two most significant noise components (local and global) rather than attempting to model all possible sources of variation. This partial action approach improves quantitative precision for the dominant noise sources while avoiding the information loss and complexity that would result from over-correcting for less significant factors.

Inventive Principle:
Principle #16Partial or excessive 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

This approach significantly increases the quantitative precision in identifying chromosomal abnormalities, such as amplified and deleted DNA subsequences, by reducing the impact of noise and improving the reliability of aberration calling in CGH data analysis.

Implementation Method 1

comparative hybridization data, including comparative genomic hybridization ('CGH') data

Methodology Applied
Scientific EffectHybridization:

Data Source

PatentUS7660675B2Method and system for analysis of array-based, comparative-hybridization data
Publication Date: 2010.02.09 AGILENT TECHNOLOGIES INC
  • US7660675B2 patent drawing
  • US7660675B2 patent drawing
  • US7660675B2 patent drawing

AI summary

Embodiments of the present invention include methods and systems for analysis of comparative genomic hybridization (“CGH”) data, including CGH data obtained from microarray experiments.