Constrained Deep Learning Network for Interpretable Biomarker Extraction

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Solution Overview

Problem

Current medical imaging technologies face challenges in generating interpretable and data-driven biomarkers, as deep learning systems lack interpretability and require large datasets, while clinical studies rely on hand-crafted features that are not reproducible or standardized, creating a gap between clinical and machine learning approaches.

Innovation Solution

The method involves applying constraints to inner nodes of a machine learning network to enforce semantic behaviors, such as correlations with known biomarkers or independence from imaging parameters, allowing for the derivation of data-driven biomarkers that are calibrated and qualified during the training process, using a combination of RADIOME and TECHNOME features to improve image processing and reduce data requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If deep learning systems are used to automatically derive image features, then feature extraction automation is improved, but interpretability and data efficiency deteriorate

Engineering Contradiction:
Improvefeature extraction automationVSAvoidinterpretability
Core Design Contradiction:
Extent of automationVSLoss of information

Solution Approach 1:

The patent introduces constrained intermediate representations within the neural network that serve as mediators between automatic feature extraction and interpretability. These constrained layers enforce semantic meanings on hidden representations, allowing the system to automatically learn features while maintaining interpretability through controlled intermediate states that can be linked to known biomarkers or imaging parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If deep learning systems are used to automatically derive image features, then feature extraction automation is improved, but data requirements increase

Engineering Contradiction:
Improvefeature extraction automationVSAvoiddata requirements
Core Design Contradiction:
Extent of automationVSQuantity of substance

Solution Approach 1:

The patent applies preliminary constraints to the neural network architecture and training process that encode prior knowledge about imaging parameters and biomarker relationships. By pre-defining these constraints before training, the system leverages existing domain knowledge to guide feature learning, reducing the amount of training data needed compared to unconstrained deep learning approaches.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If hand-crafted features are used in clinical studies, then feature interpretability is improved, but reproducibility and standardization deteriorate

Engineering Contradiction:
Improvefeature interpretabilityVSAvoidreproducibility
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent transforms hand-crafted feature extraction into a learned parameter system where the network automatically optimizes feature representations while constraints maintain interpretability. By changing from fixed hand-crafted parameters to learned parameters with semantic constraints, the system achieves both reproducibility through automated learning and interpretability through enforced semantic meanings on the learned features.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If constraints are applied to inner nodes of machine learning network, then biomarker qualification is improved, but system complexity increases

Engineering Contradiction:
Improvebiomarker qualificationVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the neural network into distinct functional layers with specific constraints applied to inner nodes. By dividing the network into segments with different constraint types (e.g., some layers constrained to match known biomarkers, others to be independent of imaging parameters), the system achieves precise biomarker qualification while managing complexity through modular constraint application rather than uniform complexity throughout the entire network.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11341632B2Method for obtaining at least one feature of interest
Publication Date: 2022.05.24 SIEMENS HEALTHINEERS AG
  • US11341632B2 patent drawing
  • US11341632B2 patent drawing
  • US11341632B2 patent drawing

AI summary

A method is for obtaining at least one feature of interest, especially a biomarker, from an input image acquired by a medical imaging device. The at least one feature of interest is the output of a respective node of a machine learning network, in particular a deep learning network. The machine learning network processes at least part of the input image as input data. The used machine learning network is trained by machine learning using at least one constraint for the output of at least one inner node of the machine learning network during the machine learning.