Contrast-Free MR Imaging via Cardiac-Synchronized Signal Subtraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vascular imaging techniques, such as X-ray angiography and MRI, face limitations in visualizing dynamic blood flow and require contrast agents, which can be invasive and pose health risks, while also providing inadequate temporal resolution for diagnosing conditions like arteriovenous malformations.
Innovation Solution
An MR imaging system that acquires high temporal and spatial resolution 3D data sets without contrast agents, using synchronized heart rate signals to differentiate blood flow from static tissue, enabling visualization of blood inflow from a spatially non-localized region with improved signal quality and speed, employing TrueFISP compatible methods for enhanced imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contrast agents are used to enhance imaging contrast, then imaging contrast is improved, but patient safety deteriorates due to nephrotoxicity and NSF risks
Solution Approach 1:
The patent extracts and removes the harmful contrast agent from the imaging system by utilizing the inherent magnetic properties of blood and tissue. The method achieves vessel visualization through signal subtraction of pre-contrast and post-contrast images, eliminating the need for Gadolinium-based contrast agents that cause nephrotoxicity and NSF.
Solution Approach 2:
The patent employs the body's own blood as the contrast source by exploiting the natural differences in magnetic signal between flowing blood and static tissue. The flowing blood's motion creates signal changes that can be detected and visualized without external contrast agents, making the system self-sufficient and safe.
2Loss of information
If conventional MRI is used to visualize blood vessels, then anatomical information is obtained, but temporal resolution deteriorates making it difficult to capture dynamic blood flow
Solution Approach 1:
The patent utilizes the periodic nature of the cardiac cycle to acquire images at specific phases. By synchronizing image acquisition with the cardiac cycle and subtracting images from different phases, the method captures dynamic blood flow information while maintaining adequate temporal resolution for clinical diagnosis.
Solution Approach 2:
The patent exploits the asymmetric motion characteristics of blood flow compared to static tissue. Blood flows continuously through the vascular system while tissue remains stationary, creating asymmetric signal changes that can be detected through subtraction imaging, thereby preserving dynamic flow information.
3Measurement precision
If spatially localized tagging is used to limit blood inflow to ROI, then imaging specificity is improved, but the ability to visualize blood flow from spatially non-localized regions deteriorates
Solution Approach 1:
The patent transitions from spatial localization to temporal localization for blood flow visualization. Instead of limiting the field of view spatially, the method uses time-resolved imaging and subtraction to selectively visualize blood flow based on its temporal characteristics, thereby expanding the coverage to include blood flow from spatially non-localized regions.
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 provides comprehensive, contrast-agent-free visualization of dynamic blood flow with high temporal and spatial resolution, improving diagnostic capabilities for vascular diseases and reducing the risk associated with contrast agents, allowing for repeated imaging without radiation or ionizing agents.
Implementation Method 1
acquires an anatomical preparation data set representing a spatially non-localized preparation 3D volume in response to a first magnetization preparation pulse sequence
Implementation Method 2
The MR imaging system, in response to a heart rate synchronization signal, acquires an anatomical preparation data set
Implementation Method 3
subtracts slice specific MR imaging data of the spatially localized anatomical imaging data set from spatially and temporally corresponding slice specific imaging data of the anatomical preparation data set to derive blood flow indicative imaging data
Data Source
AI summary
A system enhances MR imaging contrast between vessels containing dynamically flowing blood and static tissue using an MR imaging system. The MR imaging system, in response to a heart rate synchronization signal, acquires an anatomical preparation data set representing a spatially non-localized preparation 3D volume in response to a first magnetization preparation pulse sequence. The MR imaging system acquires a spatially localized anatomical imaging data set representing a second imaging volume. The MR imaging system subtracts slice specific MR imaging data of the spatially localized anatomical imaging data set from spatially and temporally corresponding slice specific imaging data of the anatomical preparation data set to derive blood flow indicative imaging data. The temporally corresponding slice specific imaging data comprises data acquired at a substantially corresponding cycle point within a heart beat cycle determined in response to said heart rate synchronization signal. The MR imaging system iteratively repeats the subtraction step for multiple adjacent slices individually comprising a spatially localized anatomical imaging data set to provide a three-dimensional imaging data set.