Adaptive Contrast Bolus Timing for Stroke CT Imaging
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Solution Overview
Problem
Current diagnostic imaging protocols for acute stroke management, such as CT angiography and CT perfusion studies, face challenges in timing the administration of second contrast agent boluses, leading to non-diagnostic images due to venous contrast contamination or delayed patient outcomes if not timed correctly.
Innovation Solution
The method involves determining the adaptive injection timing for a second contrast bolus based on individual patient-specific arterial inflow and venous outflow functions estimated from a first contrast bolus, using machine learning models and fallback timing to ensure diagnostic image quality and timely scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a timing bolus scan is performed to personalize CTP/CTA scan prescription, then the contrast injection timing can be optimized for each patient, but the total time required increases by five minutes or more
Solution Approach 1:
The patent combines the timing bolus scan with the actual CTP/CTA scan by using the same contrast bolus for both timing measurement and diagnostic imaging. The system acquires timing data during the first pass of the contrast bolus and then immediately performs the diagnostic scan during the second pass, eliminating the need for separate timing scans and reducing total examination time while maintaining personalized timing optimization.
Solution Approach 2:
The system performs preliminary estimation of arterial inflow function and venous outflow function using a small subset of data from the beginning of the contrast enhancement curve. This preliminary action allows the system to predict optimal scan timing parameters without waiting for complete contrast washout, enabling earlier initiation of the diagnostic scan while still achieving personalized timing optimization.
2Measurement precision
If separate CTA and CTP studies are performed, then each study can be optimized independently, but five to seven minutes must elapse between acquisitions for contrast washout
Solution Approach 1:
The patent merges CTA and CTP studies into a single continuous scan protocol. The system acquires CTA data during the arterial phase when contrast is in the arteries, then immediately transitions to CTP acquisition during the venous phase when contrast has distributed to the tissue. This eliminates the need for contrast washout between separate studies while maintaining independent optimization of each study type through phase-specific imaging parameters.
Solution Approach 2:
The system maintains continuous data acquisition throughout the entire contrast bolus passage, continuously adjusting imaging parameters based on real-time contrast concentration measurements. This continuous useful action allows both CTA and CTP data to be collected in an uninterrupted sequence without idle time for contrast washout, maximizing the utilization of the contrast agent's passage through the body.
3Ease of operation
If fixed timing protocols are used for contrast injection, then the scanning process is simpler to execute, but venous contrast contamination occurs leading to non-diagnostic images
Solution Approach 1:
The system dynamically adjusts scan timing parameters based on real-time measurement of the patient's actual contrast kinetics. Instead of using fixed predetermined timing, the system continuously monitors contrast concentration in the blood and automatically adjusts the timing of CTA and CTP acquisitions to match the patient's unique arterial inflow and venous outflow characteristics, ensuring optimal image quality while maintaining operational simplicity through automated control.
Solution Approach 2:
The system implements feedback control by measuring actual contrast concentration during the scan and using this information to adjust subsequent imaging parameters. The real-time monitoring of contrast enhancement provides feedback that allows the system to optimize scan timing mid-examination, preventing venous contamination by automatically delaying or advancing acquisitions based on the actual contrast passage rate observed in that specific patient.
Data Source
AI summary
Methods and systems are provided for adaptive scan control. In one embodiment, a method includes, upon a first contrast injection of a first contrast bolus, processing acquired projection data of a subject to measure a contrast signal of the first contrast bolus, setting a timing for a second contrast injection of a second contrast bolus to a fallback injection timing, and responsive to identifying an adaptive injection timing for the second contrast injection based on the contrast signal before the fallback injection timing is reached, updating the timing for the second contrast injection to the adaptive injection timing and commanding initiation of the second contrast injection at the adaptive injection timing, otherwise commanding initiation of the second contrast injection at the fallback injection timing.