Dynamic Contrast-Adaptive PE Detection in CT Angiography

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Solution Overview

Problem

Current methods for detecting pulmonary emboli using CT pulmonary angiography face challenges due to suboptimal mixing of radiocontrast in blood, leading to false positives and false negatives, which can result from factors like blood flow rate and improper mixing artifacts, affecting the accuracy and reliability of the diagnosis.

Innovation Solution

The method involves automatically detecting the level of radiocontrast at the pulmonary artery trunk by analyzing CT images, categorizing it into different categories, and using trained object classifiers to detect pulmonary embolism candidates, thereby adapting the detection parameters to optimize image acquisition and reduce mixing artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If radiocontrast is administered to visualize vessels in CTPA images, then vessel visualization is improved, but mixing artifacts occur due to improper mixing of radiocontrast in blood

Engineering Contradiction:
Improvevessel visualizationVSAvoidmixing artifacts
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts detection parameters based on the measured contrast level in the pulmonary artery trunk. By categorizing images into different contrast level groups and applying group-specific detection parameters, the system adapts to varying mixing conditions and reduces false positives while maintaining vessel visualization quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system measures the actual contrast level in the pulmonary artery trunk and uses this feedback to automatically adjust detection parameters. This closed-loop approach allows the system to compensate for improper mixing by adapting its detection sensitivity based on the observed contrast distribution

Inventive Principle:
Principle #23Feedback

2Measurement precision

If manual review of CT data is performed to detect PEs, then detection accuracy is improved, but time consumption increases significantly

Engineering Contradiction:
Improvedetection accuracyVSAvoidreview time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system introduces an automatic detection algorithm as an intermediary between the CT data and the radiologist. This algorithm pre-processes the data, identifies suspicious regions, and presents them to the radiologist for confirmation, thereby reducing the time required while maintaining high detection accuracy through the radiologist's expertise

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system segments the CT data analysis into two parts: automatic detection of potential PE regions by the algorithm, and selective review of only those regions by the radiologist. This segmentation reduces the overall review time while maintaining accuracy by focusing human expertise on the most suspicious areas

Inventive Principle:
Principle #1Segmentation

3Productivity

If automatic PE detection is implemented to reduce review time, then productivity is improved, but false positive rate increases due to image abnormalities

Engineering Contradiction:
Improvereview efficiencyVSAvoidfalse positive rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system applies different detection parameters and thresholds based on the local contrast level characteristics of each image or region. By adapting the detection criteria to the specific contrast conditions, the system reduces false positives caused by image abnormalities while maintaining high sensitivity for actual PEs

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts detection parameters based on the measured contrast level rather than using fixed thresholds. This dynamic adaptation allows the system to optimize its sensitivity and specificity for each imaging condition, reducing false positives while maintaining productivity

Inventive Principle:
Principle #15Dynamics

4Device complexity

If contrast level is not monitored to correct for improper mixing, then device complexity is reduced, but diagnostic reliability deteriorates due to false positives and negatives

Engineering Contradiction:
Improvesystem simplicityVSAvoiddiagnostic accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system automatically measures the contrast level in the pulmonary artery trunk and adjusts its own detection parameters without requiring external intervention or complex additional hardware. This self-service approach maintains simplicity while improving reliability through adaptive parameter adjustment

Inventive Principle:
Principle #25Self-service

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 enhances the accuracy and reliability of pulmonary emboli detection by correcting for improper mixing of radiocontrast, minimizing false positives and negatives, and ensuring optimal CTPA studies, thus improving patient treatment outcomes.

Implementation Method 1

A level of contrast at a pre-determined anatomic location of the patient is acquired

Methodology Applied
Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentUS8447081B2Pulmonary emboli detection with dynamic configuration based on blood contrast level
Publication Date: 2013.05.21 SIEMENS HEALTHINEERS AG
  • US8447081B2 patent drawing
  • US8447081B2 patent drawing
  • US8447081B2 patent drawing

AI summary

A method for automatically detecting pulmonary embolism (PE) candidates within medical image data using an image processing device includes administering radiocontrast into a patient. A sequence of computed tomography (CT) images is acquired. A level of radiocontrast at a pulmonary artery trunk of the patient is determined. One or more PE candidates are detected within a pulmonary artery tree of the patient based on the determined level of radiocontrast at the pulmonary artery trunk. The one or more detected PE candidates are displayed.