CT Pulmonary Emboli Detection Non-Linear Contrast Filtering

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Solution Overview

Problem

Conventional methods for detecting pulmonary emboli in CT images often result in false positives due to assumptions about normal anatomy, leading to incorrect identification of lymph nodes, water-filled airways, and other artifacts as emboli.

Innovation Solution

A system and method that acquire CT image data, apply a lung mask, perform non-linear contrast enhancement, filter out false positives using various techniques, and reconstruct images to isolate and output a final set of pulmonary emboli candidates, reducing false positives through a series of filtering steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods with simple thresholds and linear contrast enhancements are used, then the processing speed is fast, but the detection accuracy deteriorates due to false positives

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the linear contrast enhancement parameter into a non-linear parameter, and changes the detection threshold from a simple fixed value to an adaptive threshold based on local image statistics. This resolves the contradiction by improving detection accuracy through parameter transformation while maintaining processing efficiency through algorithmic optimization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary contrast enhancement and noise filtering before the main detection process. By preparing the image data in advance with non-linear contrast enhancement, the subsequent detection algorithms work more efficiently with pre-processed data, resolving the contradiction between accuracy and processing complexity.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If large banks of information from many CT images are used to train classifiers, then the detection accuracy improves, but the processing time increases

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

Solution Approach 1:

The patent segments the detection process into distinct stages: contrast enhancement, candidate region identification, and verification. By dividing the processing into segments with progressively stricter filtering criteria, the system achieves high detection accuracy while minimizing the amount of data that requires intensive classification processing, thus reducing overall processing time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by using simplified detection criteria for initial candidate identification, then applying more rigorous verification only to promising candidates. This avoids the need to process all image data with full classification complexity, resolving the contradiction between accuracy and processing time.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If simple thresholds are used for detection, then the processing is simple and fast, but false positives increase due to normal anatomy being misidentified

Engineering Contradiction:
Improveprocessing efficiencyVSAvoiddetection reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by using adaptive thresholds that vary across different regions of the image based on local tissue characteristics. Instead of a single global threshold, each region has optimized detection parameters tailored to its specific anatomical features, improving reliability while maintaining processing efficiency through localized rather than exhaustive analysis.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8542893B2System and method of pulmonary emboli detection for computed tomography
Publication Date: 2013.09.24 GE PRECISION HEALTHCARE LLC
  • US8542893B2 patent drawing
  • US8542893B2 patent drawing
  • US8542893B2 patent drawing

AI summary

A system and method includes acquisition of a set of image data comprising a plurality of image voxels and isolation of a set of pulmonary emboli candidates from the plurality of image voxels. The system and method also includes application of a non-linear contrast enhancement to the set of pulmonary emboli candidates, filtration of the enhanced set of pulmonary emboli candidates, output of a final set of pulmonary emboli candidates, and creation of an image comprising the final set of pulmonary emboli candidates.