Arterial Spin Labeling MRI for Non-Contrast Cardiac Imaging
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Solution Overview
Problem
Conventional cardiac MRI examinations using contrast media have limitations in temporal and spatial resolution, leading to variable image quality and diagnosis, and pose risks due to gadolinium-based contrast medium side effects and medication concerns.
Innovation Solution
A magnetic resonance imaging apparatus and method that performs non-contrast MRA imaging using a time-SLIP sequence for ECG-synchronized blood flow imaging, allowing for high-resolution 3D visualization of coronary arteries without contrast media, by selectively labeling and suppressing blood signals to enhance image contrast and reduce background noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If contrast media is used for cardiac MRI imaging, then image contrast is improved, but patient safety deteriorates due to gadolinium-based contrast medium side effects
Solution Approach 1:
The patent extracts and removes the harmful contrast media from the imaging system by implementing a non-contrast MRA method using arterial spin labeling. The technique achieves blood flow imaging without gadolinium-based contrast agents, thereby eliminating the associated side effects while maintaining diagnostic capability through alternative signal generation mechanisms.
Solution Approach 2:
The patent introduces an intermediary mechanism (arterial spin labeling with time-SLIP sequence) that mediates between the need for image contrast and patient safety. By using magnetically labeled blood as an endogenous contrast source rather than exogenous contrast media, the system achieves the desired image differentiation without harmful substances.
2Illumination intensity
If conventional CE MRA method is used for perfusion study, then blood flow visualization is improved, but temporal and spatial resolution deteriorate leading to variable image quality
Solution Approach 1:
The patent employs periodic action through ECG-gating and rhythmic application of labeling pulses in the time-SLIP sequence. The imaging is synchronized with the cardiac cycle, acquiring data at specific phases (diastole) repeatedly, which improves temporal resolution and consistency of blood flow visualization without requiring contrast media.
Solution Approach 2:
The patent changes key imaging parameters by using a different pulse sequence (time-SLIP) with optimized labeling duration, inversion time, and acquisition timing. These parameter modifications enable high-resolution 3D imaging with improved temporal and spatial resolution compared to conventional CE MRA methods.
3Measurement precision
If dynamic imaging is performed with contrast medium administration, then ischemic part detection is improved, but diagnostic consistency deteriorates due to variable image quality
Solution Approach 1:
The patent performs preliminary action by applying spatially selective inversion pulses to label blood in the aorta before it reaches the myocardium. This pre-labeling approach ensures that the blood signal is differentiated before entering the imaging region, providing consistent and reliable ischemic part detection without the variability associated with contrast medium timing and distribution.
4Object-affected harmful factors
If non-contrast MRA is performed without selective labeling, then patient safety is improved, but image contrast and blood flow visualization deteriorate
Solution Approach 1:
The patent applies local quality by using spatially selective inversion pulses that affect only specific regions (aorta or coronary arteries) rather than the entire imaging volume. This localized labeling creates high contrast between labeled blood and unlabeled tissue in the specific vessels of interest, achieving excellent blood flow visualization without contrast media.
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 high-resolution, non-contrast cardiac imaging with improved temporal and spatial resolution, allowing for precise detection of ischemic and infarcted areas without the need for gadolinium-based contrast agents, reducing risks and enhancing diagnostic accuracy.
Implementation Method 1
MRI (magnetic resonance imaging) which magnetically excites nuclear spin of an object with an RF (radio frequency) signal having the Larmor frequency and reconstructs an image based on NMR (nuclear magnetic resonance) signals generated due to the excitation
Implementation Method 2
A magnetic resonance imaging apparatus and method that performs non-contrast MRA imaging using a time-SLIP sequence for ECG-synchronized blood flow imaging, allowing for high-resolution 3D visualization of coronary arteries without contrast media, by selectively labeling and suppressing blood signals to enhance image contrast and reduce background noise
Data Source
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AI summary
According to one of the aspects of an MRI apparatus of the present invention, the MRI apparatus includes an imaging data acquiring unit and a blood flow information generating unit. The imaging data acquiring unit acquires imaging data from an imaging region including myocardium, without using a contrast medium, by applying a spatial selective excitation pulse to a region including at least a part of an ascending aorta for distinguishably displaying inflowing blood flowing into the imaging region. The blood flow information generating unit generates blood flow image data based on the imaging data.