Adaptive RF Pulse Phase Offset for Non-Contrast MRA
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Solution Overview
Problem
Current non-contrast Magnetic Resonance Angiography (MRA) methods face challenges in obtaining high signal intensity and clear blood flow images, particularly in regions with low flow velocity, and struggle to completely remove vein signals from diastole and systole images.
Innovation Solution
A magnetic resonance imaging apparatus that sets capturing conditions by adjusting the angle offset of RF pulses and gradient pulses based on blood flow velocity, optimizing the phase difference between echoes to enhance signal intensity and distinguish artery and vein signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional non-contrast MRA methods are used, then the imaging process is simple, but the signal intensity is insufficient and blood flow images are not clear
Solution Approach 1:
The patent applies parameter changes by adjusting the angle offset of RF pulses and gradient pulses based on blood flow velocity. Specifically, the angle offset is modified to optimize the phase difference between echoes, which directly controls signal intensity. This allows the system to adapt to different blood flow velocities and achieve high signal intensity without requiring complex additional hardware or contrast agents.
Solution Approach 2:
The patent implements dynamics by making the capturing conditions adaptive rather than fixed. The angle offset and gradient pulse parameters are dynamically adjusted according to the measured blood flow velocity. This dynamic adaptation enables the system to optimize signal intensity for varying physiological conditions while maintaining a relatively simple overall system architecture.
2Measurement precision
If conventional MRA methods are used, then the imaging process is straightforward, but artery and vein signals cannot be effectively distinguished
Solution Approach 1:
The patent applies local quality by optimizing parameters specifically for different blood flow characteristics. Different angle offsets and gradient pulse settings are used for arteries versus veins based on their different flow velocities. This localized optimization allows effective differentiation between artery and vein signals while keeping the overall method relatively simple.
Solution Approach 2:
The patent uses parameter changes to distinguish artery and vein signals by adjusting the angle offset and gradient pulse intensity according to blood flow velocity. These parameter adjustments create distinct signal characteristics for arteries and veins, enabling effective separation without complex additional processing or hardware.
3Reliability
If conventional MRA methods are used, then the scanning process is simple, but artifacts and contamination from vein signals remain
Solution Approach 1:
The patent implements dynamics by using adaptive capturing conditions that respond to actual blood flow velocity measurements. The angle offset and gradient parameters are dynamically optimized based on measured flow characteristics, which suppresses artifacts and vein signal contamination. This dynamic approach improves image reliability while maintaining a relatively simple overall system.
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 results in higher intensity blood flow signals and improved separation of artery and vein images, reducing artifacts and contamination, thereby producing clearer and more accurate blood flow images.
Implementation Method 1
A MRI (magnetic resonance imaging) method is an imaging method that excites an atomic nuclear spin of an object disposed in a magnetostatic field by using an RF (radio frequency) signal having a Larmor frequency and reconstructs the image on the basis of an MR (magnetic resonance) signal generated by the excitation
Implementation Method 2
The FBI method performs a three dimensional scanning that encodes a frequency in a direction substantially equal to a movement direction of the blood vessel by controlling a gradient magnetic field
Implementation Method 3
a dephase pulse or refocusing pulse is applied to a gradient magnetic field pulse is designed. According to the flow-dephasing method, due to the dephase pulse or the refocusing pulse, it is possible to increase the relative signal difference between a signal value from the blood flow of high velocity and a signal value from the blood flow of low velocity
Data Source
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AI summary
A magnetic resonance imaging apparatus includes a blood flow velocity acquiring unit that acquires a flow velocity of the blood flow of an object, a capturing condition setting unit that, on the basis of the flow velocity of the blood flow acquired by the blood flow velocity acquiring unit, sets at least one of a transmitting phase of a transmitted exciting pulse, a transmitting phase of a refocusing pulse, a shift amount of the relative phase difference between the transmitted exciting phase and the refocusing pulse, and an intensity of a gradient pulse in a readout direction as a capturing condition, and a blood flow image capturing unit that creates a blood flow image of the object by performing an imaging scan on the basis of the capturing condition set by the capturing condition setting unit.