Patient-Specific Contrast Medium Optimization in CT Imaging

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Solution Overview

Problem

Current x-ray imaging technologies, particularly in computed tomography, face challenges in minimizing the amount of contrast medium used while maintaining a high contrast-to-noise ratio, especially for patients undergoing examinations where high doses of contrast media can cause undesired side-effects, especially in older patients or those with impaired kidney functions.

Innovation Solution

A method and device that utilize patient-specific data to optimize and minimize the contrast medium dose by determining the required amount based on patient-specific cross-sectional data, x-ray source settings, and image reconstruction techniques, allowing for the calculation of monoenergetic image data from multi-energy measurements to achieve the desired contrast-to-noise ratio with reduced radiation dose.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high dose of contrast medium is used to achieve high image contrast, then the contrast-to-noise ratio is improved, but the harmful side-effects increase

Engineering Contradiction:
Improvecontrast-to-noise ratioVSAvoidside-effects of contrast medium
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the energy parameter of x-ray radiation by using different tube voltages (e.g., 80 kV vs. 140 kV) to optimize the contrast-to-noise ratio. By adjusting the x-ray energy spectrum to match the absorption characteristics of iodine, the system achieves high image contrast with lower contrast medium doses, thereby reducing side-effects while maintaining diagnostic quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adapts the x-ray energy spectrum and contrast medium dosage to patient-specific characteristics such as body weight, body composition, and examination type. This dynamic optimization allows the system to use the minimum necessary contrast medium dose while maintaining high CNR, thus reducing harmful side-effects without compromising image quality

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If high atomic number elements are used in contrast media to increase x-ray absorption, then the image contrast is improved, but the radiation dose increases

Engineering Contradiction:
Improveimage contrastVSAvoidradiation dose
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the x-ray energy spectrum parameters to match the absorption edges of iodine (atomic number 53). By using tube voltages that generate photons with energies just above the iodine K-edge (33.2 keV), the system maximizes the photoelectric effect and x-ray absorption by iodine, achieving high image contrast with lower radiation doses compared to using higher atomic number elements

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 enables the reduction of contrast medium dosage while ensuring a sufficient contrast-to-noise ratio, thereby minimizing side-effects and optimizing imaging quality, particularly beneficial for patients requiring lower contrast medium loads.

Implementation Method 1

at least one x-ray tube (2) for scanning the patient (7) with x-ray radiation having a specific energy spectrum

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

Implementation Method 2

The x-ray density of contrast media increases with the atomic number of the contrasting element... the attenuation coefficient of the contrasting element, its local concentration, in combination with the photon spectrum

Methodology Applied
Scientific EffectPhotoelectric absorption: Absorption (EM radiation)

Implementation Method 3

contrast media (CM) containing iodine are used nowadays for presenting body fluids, organs and pathological processes... the x-ray density of contrast media increases with the atomic number of the contrasting element

Methodology Applied
Scientific EffectX-ray absorption by contrast medium: Absorption (EM radiation)

Implementation Method 4

a detector (3) for measuring the attenuation of the x-ray radiation on passage through the patient (7)

Methodology Applied
Scientific EffectX-ray detection: X-Ray

Data Source

PatentUS9907529B2Patient-dependent optimization of the amount of contrast medium
Publication Date: 2018.03.06 SIEMENS HEALTHINEERS AG
  • US9907529B2 patent drawing
  • US9907529B2 patent drawing

AI summary

A method and an apparatus are disclosed for patient-dependent optimization and reduction of the contrast medium amount. An embodiment includes provisioning patient-specific data, containing information about a patient cross-section relevant for the imaging measurement; establishing CT values and/or CNR values of a contrast medium to be expected for at least one region of interest of the patient for different candidate settings of x-ray source arrangement and/or of an image reconstruction device; determining a relevant candidate contrast medium amount for the different candidate settings, which would lead to a CT value or CNR value of the contrast medium which corresponds to the CT value or CNR value of the contrast medium at the reference setting of the x-ray source arrangement and/or image reconstruction device; and displaying an optimum relative candidate contrast medium amount and of the associated candidate setting.