Lesion Proposal Generator Conditioning for Medical Image Annotation

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Solution Overview

Problem

Existing medical image databases, such as DeepLesion, suffer from uncertainties and incomplete annotations, making them ill-suited for training machine learning systems, as they often lack comprehensive lesion annotations, which are costly and time-consuming to create.

Innovation Solution

A method and system that condition a lesion proposal generator (LPG) using a subset of annotated images to enhance lesion annotations, integrating it with a selective lesion proposal classifier (LPC) to reduce false positives and harvest additional annotations from unannotated images, forming 3D bounding boxes for improved lesion detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If comprehensive manual annotation is performed on all medical images, then annotation completeness improves, but time consumption and cost increase significantly

Engineering Contradiction:
Improveannotation completenessVSAvoidannotation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary automated annotation using the conditioned LPG to generate initial lesion proposals before any manual review. This preliminary action creates a draft annotation set that covers most lesions, reducing the subsequent manual annotation workload while maintaining high completeness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses harvested annotations from automatically annotated images to iteratively improve and re-condition the LPG, enabling it to perform better annotation tasks autonomously. This self-improving mechanism reduces dependency on continuous manual annotation while progressively enhancing annotation quality and completeness.

Inventive Principle:
Principle #25Self-service

2Productivity

If automated lesion detection is applied to all images, then annotation speed improves, but false-positive rate increases

Engineering Contradiction:
Improveannotation speedVSAvoidfalse-positive rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements feedback loops where harvested annotations from automated detection are used to re-condition the LPG, improving its accuracy. Additionally, the system iteratively refines detection parameters based on performance metrics, continuously reducing false positives while maintaining high detection speed across the dataset.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from 2D slice-based annotation to 3D volumetric annotation, leveraging spatial relationships across multiple slices to distinguish true lesions from false positives. This dimensional enhancement provides contextual information that reduces false-positive rates while maintaining automated processing speed.

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

3Ease of manufacture

If 2D slice-based annotation is used, then annotation process is simple, but lesion detection recall is insufficient

Engineering Contradiction:
Improveannotation simplicityVSAvoidlesion detection recall
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system extends annotation from 2D slices to 3D volumes by aggregating lesion proposals across multiple slices and applying spatial consistency constraints. This 3D approach captures lesions that span multiple slices, significantly improving detection recall while building upon the simpler 2D annotation foundation through iterative refinement.

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

4Quantity of substance

If existing medical image databases are used for training, then data availability improves, but annotation quality deteriorates due to uncertainties and incomplete annotations

Engineering Contradiction:
Improvedata availabilityVSAvoidannotation quality
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The system extracts and isolates high-confidence lesion annotations from the conditioned LPG output, separating them from low-confidence or false-positive proposals. This extraction process creates a curated subset of reliable annotations from the larger automated output, improving overall annotation quality while utilizing the abundant data from existing databases.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11620745B2Method and system for harvesting lesion annotations
Publication Date: 2023.04.04 PING AN TECH (SHENZHEN) CO LTD
  • US11620745B2 patent drawing
  • US11620745B2 patent drawing
  • US11620745B2 patent drawing

AI summary

A method of harvesting lesion annotations includes conditioning a lesion proposal generator (LPG) based on a first two-dimensional (2D) image set to obtain a conditioned LPG, including adding lesion annotations to the first 2D image set to obtain a revised first 2D image set, forming a three-dimensional (3D) composite image according to the revised first 2D image set, reducing false-positive lesion annotations from the revised first 2D image set according to the 3D composite image to obtain a second-revised first 2D image set, and feeding the second-revised first 2D image set to the LPG to obtain the conditioned LPG, and applying the conditioned LPG to a second 2D image set different than the first 2D image set to harvest lesion annotations.