Fluid Velocity Calculation Using Attenuation Gradients in CT Imaging
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Solution Overview
Problem
Conventional methods for determining blood flow velocity in CT imaging are limited by the need for parallel movement between the scanning system and the object, restricted detector size, and require multiple scans, making them inaccurate and impractical for non-parallel trajectories and small detectors.
Innovation Solution
A method that acquires attenuation values based on image data, determines a temporally and spatially delineated region with linear properties, and calculates fluid velocity using temporal and spatial gradients, allowing for flexible use with conventional CT devices and various scan types, including spiral acquisitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional methods are used to determine blood flow velocity in CT imaging, then measurement can be performed, but the method is limited by the need for parallel movement between scanning system and object, restricted detector size, and requires multiple scans
Solution Approach 1:
The patent changes the mathematical parameters used for velocity calculation from traditional time-offset methods to gradient-based methods using temporal and spatial derivatives. This allows the system to handle non-parallel trajectories and various scan types (including spiral acquisitions) while maintaining measurement accuracy, resolving the contradiction between adaptability and reliability.
2Measurement precision
If multiple scans are performed to determine blood flow velocity, then measurement can be achieved, but the process becomes complex and impractical
Solution Approach 1:
The patent extracts the velocity information directly from a single scan's attenuation data by calculating temporal and spatial gradients. This eliminates the need for multiple scans while maintaining measurement precision, thereby reducing scan process complexity without sacrificing velocity measurement accuracy.
3Ease of manufacture
If detector size is restricted, then conventional CT devices can be used, but velocity measurement becomes inaccurate
Solution Approach 1:
The patent changes the calculation methodology to use gradient-based velocity determination that is independent of detector size constraints. By using temporal and spatial gradients of attenuation data, the system achieves accurate velocity measurements with conventional CT devices regardless of detector dimensions, resolving the contradiction between device compatibility and measurement precision.
4Reliability
If parallel movement between scanning system and object is required, then conventional methods work, but the method cannot handle non-parallel trajectories
Solution Approach 1:
The patent transforms the velocity calculation from time-offset-based to gradient-based parameters. This mathematical transformation allows the system to reliably determine velocity along arbitrary trajectories including non-parallel paths, eliminating the constraint of requiring parallel movement between scanning system and object while maintaining measurement reliability.
Data Source
AI summary
A method for determining the velocity of a fluid in a volume to be imaged of an examination object with the aid of an imaging method is described. Attenuation values are acquired based upon image data of the volume to be imaged, depending on location and time. A temporally and spatially delineated region is specified based upon the acquired attenuation data, in which the acquired attenuation data behaves approximately linearly. Subsequently, temporal and/or spatial gradients and/or a combination of a temporal and a spatial gradient are determined based upon the attenuation values associated with the temporally and spatially delineated region. Finally, the velocity of the fluid is calculated based upon the determined temporal and/or spatial gradients or from the combination of a temporal and a spatial gradient and from the temporal gradient. A fluid velocity determining device, non-transitory computer readable medium and a computed tomography system are also described.