Fetal Anatomy Detection Using Constrained Probabilistic Boosting Tree

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Solution Overview

Problem

Current methods for automatic fetal ultrasound measurements are user-dependent, time-consuming, and prone to errors, leading to inconsistent results and increased risk of Repetitive Stress Injury for experts, while also being insufficient in capturing complex fetal anatomy appearances and robust against speckle noise and signal drop-out.

Innovation Solution

A system utilizing a constrained probabilistic boosting tree classifier is trained on expert-annotated databases to automatically detect and measure fetal anatomical structures in ultrasound images, enabling precise segmentation and measurement of bi-parietal diameter, head circumference, abdominal circumference, femur length, humerus length, and crown rump length without user input, and is efficient enough to run in under one second.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual measurement by expert users is used, then measurement accuracy is maintained, but examination time increases and user dependency persists

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidexamination time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system creates a computational copy of expert measurement capabilities through machine learning models trained on expert-annotated data. The constrained probabilistic boosting tree classifier learns to replicate expert decision-making patterns, enabling automated measurements that achieve expert-level accuracy without requiring actual expert involvement in each examination.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

Expert knowledge is captured and stored in advance through annotation of training images. The system performs preliminary learning during the training phase, encoding expert measurement strategies into the classifier. This allows the system to execute measurements automatically during actual examinations without requiring expert participation, significantly reducing examination time while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If manual measurement by expert users is used, then measurement quality is maintained, but risk of Repetitive Stress Injury increases

Engineering Contradiction:
Improvemeasurement qualityVSAvoidrisk of Repetitive Stress Injury
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system enables self-service measurement capability, where the ultrasound system automatically performs measurements without requiring expert users to manually identify anatomical structures. The constrained probabilistic boosting tree classifier independently detects fetal anatomies and computes measurements, eliminating the need for repetitive manual operations that cause physical strain while maintaining measurement quality through learned expert patterns.

Inventive Principle:
Principle #25Self-service

3Device complexity

If explicit encoding of prior knowledge is used, then measurement framework is established, but ability to capture complex fetal anatomy appearances is insufficient

Engineering Contradiction:
Improvemeasurement frameworkVSAvoidability to capture complex appearances
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transforms the measurement approach from fixed geometric models to adaptive appearance-based modeling. The constrained probabilistic boosting tree classifier learns complex appearance patterns directly from image data, automatically adapting to variations in fetal anatomy appearances. This allows the system to handle diverse and complex appearances that cannot be captured by predetermined geometric assumptions.

Inventive Principle:
Principle #35Parameter changes

4Loss of time

If automated detection is implemented, then examination time is reduced, but robustness to speckle noise and signal drop-out must be maintained

Engineering Contradiction:
Improveexamination timeVSAvoidrobustness to noise
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The constrained probabilistic boosting tree classifier incorporates feedback mechanisms through its ensemble structure and probability-based decision making. The system evaluates multiple features and combines their probabilities to make robust detection decisions, allowing it to tolerate noise and signal variations. This feedback-based approach enables fast automated detection while maintaining reliability in noisy ultrasound conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS7995820B2System and method for detection of fetal anatomies from ultrasound images using a constrained probabilistic boosting tree
Publication Date: 2011.08.09 SIEMENS MEDICAL SOLUTIONS USA INC
  • US7995820B2 patent drawing
  • US7995820B2 patent drawing
  • US7995820B2 patent drawing

AI summary

A method for detecting fetal anatomic features in ultrasound images includes providing an ultrasound image of a fetus, specifying an anatomic feature to be detected in a region S determined by parameter vector θ, providing a sequence of probabilistic boosting tree classifiers, each with a pre-specified height and number of nodes. Each classifier computes a posterior probability P(y|S) where yε{−1,+1}, with P(y=+1|S) representing a probability that region S contains the feature, and P(y=−1|S) representing a probability that region S contains background information. The feature is detected by uniformly sampling a parameter space of parameter vector θ using a first classifier with a sampling interval vector used for training said first classifier, and having each subsequent classifier classify positive samples identified by a preceding classifier using a smaller sampling interval vector used for training said preceding classifier. Each classifier forms a union of its positive samples with those of the preceding classifier.