Contrast Agent Bolus Timing Prediction in MRI
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Solution Overview
Problem
Current methods for synchronizing contrast agent bolus timing in contrast-enhanced Magnetic Resonance (MR) imaging are time-consuming, inaccurate, and often result in artefact-affected examination results, particularly in peripheral angiography, due to incomplete knowledge of individual cardiovascular conditions and the need for a test bolus measurement.
Innovation Solution
The method predicts the broadening of a contrast agent bolus by determining blood flow properties using phase contrast magnetic resonance measurements without contrast agent, establishing correlations with patient-specific parameters to optimize the time profile of contrast agent concentration during the first flooding-in phase, allowing for accurate synchronization without a test bolus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test bolus measurement is performed to determine bolus arrival time and broadening, then the timing accuracy of contrast agent flooding is improved, but the examination time and complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by measuring blood flow properties (velocity, volume flow) before the actual contrast-enhanced MR examination using phase contrast MRI without contrast agent. These preliminary measurements enable prediction of bolus broadening and arrival time, eliminating the need for a separate test bolus measurement during the examination, thus saving time while maintaining timing accuracy
Solution Approach 2:
The patent replaces the mechanical/test-based bolus timing method (injecting a test bolus and measuring its arrival) with a physics-based prediction method using phase contrast MRI to measure blood flow properties. This substitution uses electromagnetic field-based flow measurement and mathematical prediction models to determine bolus timing parameters without physical contrast agent injection, reducing examination time and complexity
2Measurement precision
If a test bolus is injected to measure bolus travel time, then the synchronization of contrast agent flooding is improved, but the quantity of contrast agent required increases
Solution Approach 1:
The patent replaces the physical test bolus injection method with a non-invasive phase contrast MRI measurement method that uses magnetic field-based velocity encoding to measure blood flow properties. This substitution eliminates the need for additional contrast agent injection while providing accurate prediction of bolus timing and broadening through mathematical models based on measured flow parameters
3Reliability
If the contrast agent flooding time is extended to 25-50 seconds as in CT, then the complete visualization of vascular system is improved, but the arterial-venous separation is compromised and image quality deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the contrast agent injection parameters (flow rate, duration, timing) based on predicted bolus broadening and arrival time. This enables optimized flooding duration specifically tailored to each patient's hemodynamics, achieving complete arterial visualization while preventing venous superposition by stopping injection before venous return occurs, thus maintaining image quality and avoiding artifacts
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 agent concentration profiling and reduces image artifacts by synchronizing the bolus timing with patient-specific cardiovascular conditions, enhancing image quality and reducing the need for additional contrast agent and background noise.
Implementation Method 1
determining blood flow properties using phase contrast magnetic resonance measurements
Data Source
AI summary
A method of predetermining the time profile of a contrast agent concentration at a vessel position is provided in the context of contrast agent-enhanced MRI of a region of interest only during the initial flooding-in phase of the contrast agent into the vessel situated in the region of interest. The method includes establishing a broadening of a contrast agent bolus profile according to the equation ΔW=W2−W1 wherein W1 is a first width of the contrast agent bolus profile at a first vessel position and W2 is a second width of a contrast agent concentration profile at a second vessel position within the region of interest. The broadening is established by determining at least one flow parameter which is dependent on at least one blood flow property of the patient at a third vessel position thereof and which correlates with the broadening of the contrast agent profile.