Dynamic Multiple Contrast Enhanced MRF for Multi-Agent Detection
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Solution Overview
Problem
Current MRI technologies are limited in their ability to simultaneously detect multiple contrast agents due to their impact on both T1 and T2 relaxation times, making it impractical to perform dynamic, multi-contrast-enhanced studies without specialized and costly hardware, which is not widely available on modern MRI scanners.
Innovation Solution
The implementation of magnetic resonance fingerprinting (MRF) techniques allows for dynamic, multi-contrast-enhanced imaging by using a series of variable sequence blocks to produce individual magnetic resonance signals from regions of interest with multiple contrast agents, enabling the simultaneous detection and quantification of T1 and T2 relaxation times, and subsequently the concentrations of these agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI pulse sequences are used to detect multiple contrast agents, then specialized hardware is required, but this increases device complexity and cost
Solution Approach 1:
The patent applies universality by designing a single MRI pulse sequence that can simultaneously detect multiple contrast agents with different relaxivities. The sequence uses variable flip angles and timing parameters to encode information from multiple agents into a single signal evolution, eliminating the need for specialized hardware and making the MRI system capable of multi-contrast imaging using standard components.
Solution Approach 2:
The patent employs parameter changes by systematically varying pulse sequence parameters (flip angles, repetition times, echo times) to create distinct signal evolutions for different contrast agents. By changing these parameters across multiple acquisitions, the system can disentangle the contributions of multiple agents through dictionary matching, achieving multi-agent detection without additional hardware.
2Productivity
If multiple contrast agents are detected simultaneously using conventional methods, then registration errors occur, but this reduces measurement precision
Solution Approach 1:
The patent merges the detection of multiple contrast agents into a single integrated MRF acquisition process. All contrast agents are imaged simultaneously during one scan session, and their signals are combined in the dictionary matching process. This eliminates the need for separate scans and subsequent registration, thereby maintaining both high productivity and measurement precision.
Solution Approach 2:
The patent introduces a signal evolution dictionary as an intermediary that mediates between the complex multi-agent signal mixture and the final quantification. The dictionary pre-stores simulated signal evolutions for various combinations of contrast agents and tissue properties, allowing the system to decode individual agent concentrations from the combined signal without requiring physical separation or registration steps.
3Measurement precision
If dynamic multi-contrast-enhanced imaging is performed with conventional sequences, then scan time increases, but this reduces productivity
Solution Approach 1:
The patent uses periodic action by implementing dynamic contrast-enhanced MRF as a series of rapidly repeated pulse sequence blocks with varying parameters. Each block acquires data at a different time point during the contrast agent passage, and the periodic repetition allows comprehensive temporal sampling to be completed in a single breath-hold or short scan, maintaining both dynamic characterization precision and clinical productivity.
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 enables the simultaneous detection of multiple MRI contrast agents without the need for expensive specialized hardware, providing more accurate and efficient imaging capabilities for clinical applications, such as cancer and cardiovascular disease diagnostics, by distinguishing molecular information from background physiology.
Implementation Method 1
acquiring, with a magnetic resonance imaging (MRI) system using a series of variable sequence blocks that cause one or more resonance species in a region of interest (ROI)
Implementation Method 2
a first pulse sequence may produce a T1-weighted signal at a first echo time (TE)
Implementation Method 3
a second pulse sequence may produce a T2-weighted signal at a second TE
Data Source
AI summary
The present disclosure provides a method of DDCE-MRF. The method can include: a) introducing two or more contrast agents to a region of interest (ROI) of a subject, the two or more contrast agents having different relaxivities; b) measuring a T1 relaxation time and a T2 relaxation time for locations within the ROI using magnetic resonance fingerprinting (MRF); c) determining, using equations that relate the different relaxivities, the T1 relaxation time, the T2 relaxation time, and concentrations of the two or more contrast agents, the concentrations of the two or more contrast agents for each of the locations within the ROI; and d) producing an image depicting the ROI based, at least in part, on the concentrations of the two or more contrast agents.