X-ray CT Scan Timing Control for Contrast Inflow
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Solution Overview
Problem
Conventional X-ray computed tomography (CT) apparatuses with contrast medium injection monitoring mechanisms face delays in determining the inflow of contrast medium due to the time required for acquiring and reconstructing projection data, and are prone to noise and artifacts in image reconstruction, which affects the accuracy of scan start timing.
Innovation Solution
An X-ray CT apparatus with a scan start timing determination circuitry that calculates a representative value based on projection data from a pre-scan at a lower dose, allowing for precise timing of the actual scan by setting a region of interest and using a predetermined threshold and view count to initiate the scan when the representative value exceeds the threshold for a specified view count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image reconstruction is performed based on acquired projection data to determine contrast medium inflow, then the CT value can be monitored in the designated area, but determination of contrast medium inflow is delayed due to acquisition and reconstruction time
Solution Approach 1:
The patent applies preliminary action by performing a pre-scan at a lower dose before the actual scan to detect contrast medium inflow in advance. The pre-scan acquires projection data and reconstructs images to determine when the contrast medium reaches the region of interest, allowing the system to trigger the actual scan at the optimal timing rather than waiting for delayed feedback from conventional real-time monitoring.
2Measurement precision
If conventional image reconstruction is used for contrast medium monitoring, then CT values can be calculated, but the determination is readily influenced by noise and artifacts in the reconstructed image
Solution Approach 1:
The patent applies local quality by focusing analysis only on a specific region of interest (ROI) where the contrast medium is expected to appear, rather than processing the entire image. By setting a predetermined region and analyzing only projection data corresponding to that region, the system reduces the influence of noise and artifacts from other areas while maintaining accurate detection of contrast medium inflow in the target area.
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 improves the accuracy of contrast medium injection monitoring by reducing the influence of noise and artifacts, and eliminates the delay associated with data acquisition and reconstruction, enabling more precise synchronization of the scan with the contrast medium inflow.
Implementation Method 1
an X-ray tube configured to generate X-rays; an X-ray detector configured to detect X-rays generated from the X-ray generation circuitry
Data Source
AI summary
According to one embodiment, an X-ray computed tomography apparatus includes an X-ray tube, an X-ray detector, a projection data generation circuitry, a setting circuitry, and a scan start timing determination circuitry. The setting circuitry configured to set a region of interest on a slice image generated by a first scan for the object. The scan start timing determination circuitry configured to determine, based on a plurality of projection data values of interest corresponding to the region of interest out of the projection data values generated by a second scan at a dose lower than that in the first scan, a timing of terminating the second scan and starting a third scan at a dose higher than that in the second scan.