Head CT Slice Localization for Intracranial Hemorrhage Detection

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Solution Overview

Problem

Existing deep learning models for diagnosing intracranial hemorrhage (ICH) on head CT scans face challenges such as labor-intensive labeling, loss of spatial information in 2D CNNs, and lack of transparency, leading to delayed medical treatment and clinical misinterpretations.

Innovation Solution

A deep learning model combining convolutional neural networks (CNNs) with recurrent neural networks (RNNs) and attention-based long-short term memory (LSTM) networks, utilizing transfer learning and scan-level labels to automate slice-level ICH localization, with Grad-CAM for model transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radiologists manually interpret CT scan slices to diagnose ICH, then diagnostic accuracy is maintained, but diagnostic time is excessive and treatment is delayed

Engineering Contradiction:
Improvediagnostic accuracyVSAvoiddiagnostic time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical system of manual radiologist interpretation with an automated deep learning system comprising CNN and RNN models. The CNN extracts features from CT scan slices while the RNN processes sequences of slices to detect ICH, eliminating the need for time-consuming manual review while maintaining diagnostic accuracy through automated pattern recognition

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

Solution Approach 2:

The deep learning model performs self-service by automatically detecting and localizing ICH without requiring manual annotation during inference. The model processes CT scan slices independently, extracting features and making diagnoses autonomously, which dramatically reduces diagnostic time while maintaining reliability

Inventive Principle:
Principle #25Self-service

2Measurement precision

If deep learning models are trained with slice-level labels for accurate ICH detection, then detection accuracy improves, but labeling cost and complexity increase significantly

Engineering Contradiction:
ImproveICH detection accuracyVSAvoidlabeling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by training the CNN model on slice-level labeled data first to learn precise feature extraction for ICH detection. This pre-training phase establishes accurate detection capabilities before the model is deployed, allowing the system to achieve high measurement precision while the labeling complexity is managed during the offline training phase rather than during clinical operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the labeling task into two distinct phases: (1) offline training phase where slice-level labels are used to train the CNN for accurate feature extraction, and (2) online inference phase where no labeling is required. This segmentation allows the system to achieve high detection accuracy during deployment without incurring ongoing labeling complexity

Inventive Principle:
Principle #1Segmentation

3Productivity

If existing deep learning models process CT scans quickly, then diagnostic efficiency improves, but prediction transparency and interpretability are reduced

Engineering Contradiction:
Improvediagnostic efficiencyVSAvoidprediction transparency
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent implements feedback by generating heatmaps that visualize which regions of the CT scan slices contributed most to the model's ICH detection decision. This feedback mechanism provides transparency into the model's reasoning process, allowing clinicians to verify that the model is basing its diagnosis on medically relevant features while maintaining rapid automated processing

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces heatmaps as an intermediary between the automated deep learning model and the clinician. The heatmaps translate the model's internal decision-making process into visual representations that highlight important regions, bridging the gap between fast automated processing and the need for interpretable, transparent predictions

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS12626402B2Precise slice-level localization of intracranial hemorrhage on head CTS with networks trained on scan-level labels
Publication Date: 2026.05.12 NORTHWESTERN UNIV
  • US12626402B2 patent drawing
  • US12626402B2 patent drawing
  • US12626402B2 patent drawing

AI summary

A weakly supervised intracranial hemorrhage (ICH) detection workflow includes training a deep learning (DL) model including a coupled convolutional neural network and recurrent neural network on a large dataset of CT scans with expert-labeled slices indicating presence or absence of ICH. Transfer learning (TL) is used to further train the DL model using a second large dataset of CT scans with only scan labels extracted from radiology reports using natural language processing (NLP). The DL model weights each slice of the scan against the final ICH diagnosis using an attention-based bi-directional long-short term memory network, where the attention weights represent slice-level ICH predictions. Model-generated heatmaps highlight significant regions of the CT scans that lead to the provided ICH predictions.