Multi-Energy CT Lesion Analysis via Spectral Attenuation

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Solution Overview

Problem

Current CT imaging methods face challenges in accurately analyzing small lesions due to partial volume effects, where the surrounding material's high attenuation values obscure the lesion's characteristics, requiring additional imaging modalities and increased patient burden.

Innovation Solution

A method using multi-energy CT recording to generate two sets of projection measurement data, reconstructing image datasets, determining pairs of attenuation values, and identifying a straight line representing the distribution of these values to differentiate between lesion and surrounding materials, thereby overcoming partial volume effects without additional devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional CT imaging methods are used to analyze small lesions, then the surrounding material's high attenuation values are captured, but the lesion's characteristics are obscured due to partial volume effects

Engineering Contradiction:
Improvelesion attenuation value accuracyVSAvoidlesion characteristics
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the attenuation values by utilizing multiple energy spectra to obtain different attenuation value pairs for the same pixel. By analyzing the distribution of these pairs and identifying characteristic patterns (such as linear relationships), the method separates lesion information from surrounding material information, effectively segmenting the mixed signal caused by partial volume effects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from analyzing single attenuation values to analyzing pairs of attenuation values obtained from different energy spectra. This dimensional expansion allows the method to distinguish between different materials (lesion vs. surrounding tissue) based on their unique attenuation characteristics across multiple energies, thereby resolving the partial volume effect problem.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If additional imaging modalities such as MR imaging are used to overcome partial volume effects, then lesion analysis accuracy is improved, but patient burden and examination effort increase

Engineering Contradiction:
Improvelesion analysis accuracyVSAvoidexamination time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent makes the CT imaging system multi-functional by utilizing multiple energy spectra within the same CT modality to achieve both anatomical imaging and material characterization. This eliminates the need for separate MR imaging examinations while maintaining the ability to accurately analyze small lesions through spectral attenuation analysis.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple energy spectrum acquisitions within a single CT examination to simultaneously obtain anatomical information and material-specific attenuation characteristics. By merging these data streams and analyzing the relationship between attenuation values at different energies, the method achieves accurate lesion analysis without requiring additional imaging modalities.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple X-ray spectra are acquired sequentially with different tube voltages, then material decomposition capability is improved, but examination time increases

Engineering Contradiction:
Improvematerial decomposition capabilityVSAvoidacquisition time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent employs periodic acquisition of multiple energy spectra during the CT scan by modulating the tube voltage in a periodic manner. This allows the system to collect data at different energy levels systematically and efficiently, enabling material decomposition while maintaining reasonable examination time through structured, repeating measurement cycles.

Inventive Principle:
Principle #19Periodic action

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

Enables reliable analysis of small lesions by accurately determining material properties within the evaluation area, reducing the need for additional imaging modalities and minimizing radiation dose, while maintaining image sharpness and reducing noise.

Implementation Method 1

The imaging methods are often based on the detection of X-ray radiation, with so-called projection measurement data being generated

Methodology Applied
Scientific EffectX-ray radiation detection: X-Ray

Implementation Method 2

projection measurement data or X-ray projection data which describe the X-ray attenuation of the patient in this direction of irradiation

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

Data Source

PatentEP3441005B1Analysis of lesions with the aid of multi-energy ct imaging
Publication Date: 2022.04.06 SIEMENS HEALTHCARE GMBH
  • EP3441005B1 patent drawingFigure 1
  • EP3441005B1 patent drawingFigure 2
  • EP3441005B1 patent drawingFigure 3

AI summary

A method for analyzing the region of interest (ROI) of an object under investigation (0) is described. The method involves acquiring two projection measurement datasets (PMD1, PMD2). These datasets are generated using multi-energy CT scanning with different effective X-ray energy spectra of the object's (0) area of ​​investigation. Two image datasets (BD1, BD2) are then reconstructed from these two projection measurement datasets (PMD1, PMD2). Furthermore, pairs of attenuation values ​​(CT1, CT2), each corresponding to a common pixel in the ROI of the two image datasets (BD1, BD2), are determined. Finally, a straight line (G) characterizing the attenuation values ​​(CT1, CT2) is calculated based on a two-dimensional distribution (V2D).Finally, a material property (ME) relating to the evaluation area (ROI) is determined based on the calculated straight line (G) and a constraint relating to the sought-after material property (ME). An image evaluation device (70) is also described. In addition, a computed tomography system (1) is described.