CT Image Correction via Measured Material Density Feedback

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Solution Overview

Problem

Existing methods for correcting material-induced effects in CT images, such as volume effects in virtual non-calcium images, often rely on theoretical models and do not account for actual measured CT values, leading to misleading interpretations.

Innovation Solution

A method and apparatus that correct material-induced effects in CT images by calculating spatially resolved material density values and using correction factors based on these values to adjust CT images, specifically addressing volume effects in virtual non-calcium images without relying on theoretical models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If volume effects are corrected using theoretical models assuming volume maintenance, then correction can be performed, but the correction does not reflect actual measured CT values leading to misleading interpretations

Engineering Contradiction:
Improvecorrection accuracyVSAvoidCT value accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by using the originally measured CT values as the basis for correction. The method calculates material density values from these measured CT values and uses them to determine correction factors, creating a feedback loop where actual measurements inform the correction process rather than relying on theoretical assumptions about volume maintenance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The correction method serves itself by using its own measured CT values to generate the correction factors needed. The system does not require external theoretical models or assumptions about volume maintenance; instead, it autonomously derives correction factors from the measured data itself, making the correction process self-sufficient and more accurate.

Inventive Principle:
Principle #25Self-service

2Loss of information

If base material decomposition is used to calculate VNCa images, then material separation is achieved, but volume effects cause CT value shifts that misrepresent physiological details

Engineering Contradiction:
Improvematerial composition informationVSAvoidCT value representation
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent extracts the volume effect component from the measured CT values by calculating material density values that account for the presence of hydroxylapatite. By separating and quantifying the volume effect contribution, the method removes its distorting influence from the VNCa image calculation, allowing accurate representation of physiological details without the misleading CT value shifts.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The method changes the parameter used for correction from theoretical volume assumptions to actual material density values derived from measured CT data. By using measured material density values to calculate correction factors, the system adapts the correction process to reflect actual physical conditions rather than relying on fixed theoretical parameters, thereby improving CT value accuracy.

Inventive Principle:
Principle #35Parameter changes

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 allows for accurate correction of volume effects directly from measured CT values, improving the reliability of CT image interpretations by ensuring that corrections are based on actual data rather than estimates, thereby enhancing diagnostic accuracy.

Implementation Method 1

Dual-energy CT (DECT) or photon-counting CT (PCCT) make it possible to break CT values down into specific pairs or triplets of material-specific CT values

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

Data Source

PatentUS20240029326A1Method and apparatus for correcting material-induced effects in CT images
Publication Date: 2024.01.25 SIEMENS HEALTHINEERS AG
  • US20240029326A1 patent drawing
  • US20240029326A1 patent drawing
  • US20240029326A1 patent drawing

AI summary

A method for correcting material-induced effects in CT images, comprising: providing a CT scan dataset including CT scan data of an object at at least two different energies; calculating a plurality of first material density values for a first substance type from the CT scan data of the CT scan dataset; calculating a plurality of correction factors based on the plurality of first material density values, wherein each correction factor is assigned to a second material density value for a second substance type; and calculating CT images from the plurality of first and second material density values, wherein at least one of the CT images is corrected via the plurality of correction factors.