Multi-Energy CT Imaging Data Correction via High kVp Projection
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Solution Overview
Problem
Multi-energy CT imaging systems face challenges in reducing noise, particularly due to high voltage stability issues and electronic noise, which affect the signal-to-noise ratio and image quality, especially in low kVp scans where signal attenuation can lead to swamped signals.
Innovation Solution
A method and apparatus for acquiring and mitigating low kVp CT imaging data by using high kVp projection data to correct and enhance low kVp data, involving techniques such as averaging, filtering, and asymmetric sampling intervals to improve signal resolution and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low kVp scans are used to improve contrast and material differentiation, then image diagnostic information is enhanced, but signal attenuation increases causing noise to swamp the signal and degrade signal-to-noise ratio
Solution Approach 1:
The patent combines high kVp and low kVp projection data through a correction process where high kVp data is used to correct low kVp data. The system merges datasets from different energy levels, using the high kVp data to compensate for signal attenuation and noise in the low kVp data, thereby maintaining both contrast enhancement and signal-to-noise ratio.
Solution Approach 2:
The patent introduces high kVp projection data as an intermediary to correct low kVp data. The high kVp data acts as a mediator that provides information about the object's attenuation characteristics, allowing the system to correct the degraded low kVp signals and recover the underlying material composition information.
2Reliability
If high kVp scans are used to improve signal strength and reduce attenuation, then signal-to-noise ratio is improved, but energy separation from low kVp data is reduced and contrast differentiation is compromised
Solution Approach 1:
The system merges high kVp and low kVp projection data to create corrected low kVp data that retains both the signal strength benefits of high kVp data and the contrast differentiation benefits of low kVp data. The combination process preserves energy separation while improving overall signal quality.
3Loss of information
If sequential scanning at different kVp levels is used to acquire multi-energy data, then material decomposition information is obtained, but scan time increases and productivity is reduced
Solution Approach 1:
The patent applies preliminary action by acquiring both high kVp and low kVp projection data during the scanning process, then using the high kVp data to correct the low kVp data in post-processing. This approach allows comprehensive material decomposition information to be obtained while maintaining scan efficiency through the use of correction algorithms rather than requiring additional scanning time.
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 effectively reduces noise in multi-energy imaging data, enhancing image quality by leveraging high kVp data to correct low kVp data issues, thereby improving signal-to-noise ratio and reducing artifacts.
Implementation Method 1
an x-ray source emits a fan-shaped or cone-shaped beam toward a subject or object
Implementation Method 2
The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the x-ray beam by the subject
Implementation Method 3
a scintillator for converting x-rays to light energy adjacent the collimator
Implementation Method 4
photodiodes for receiving the light energy from the adjacent scintillator and producing electrical signals therefrom
Implementation Method 5
Energy sensitive detectors may be used such that each x-ray photon reaching the detector is recorded with its photon energy
Implementation Method 6
two physical processes dominate the x-ray attenuation: (1) Compton scatter and the (2) photoelectric effect
Implementation Method 7
two physical processes dominate the x-ray attenuation: (1) Compton scatter and the (2) photoelectric effect
Data Source
Figure 1~2
Figure 3
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AI summary
A CT system (10) includes a rotatable gantry (12) having an opening (48) for receiving an object (22) to be scanned, and a controller (28) configured to apply a first kVp (452) for a first time period (454), apply a second kVp (456) for a second time period (458), wherein the second time period (458) is different from the first time period (454), acquire a first asymmetric view dataset (550) during at least a portion of the first time period (454), acquire a second asymmetric view dataset (554) during at least a portion of the second time period (458), and generate an image using the acquired first and second asymmetric view datasets (550, 554).