2D Fast Spin Echo MRI With Variable Flip Angle BLADE Correction
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Solution Overview
Problem
Existing two-dimensional fast spin echo magnetic resonance imaging (MRI) techniques face challenges in accelerating data acquisition while maintaining image quality, particularly due to motion artifacts and blurred images caused by increasing blade width, which leads to inefficient scanning and improper diagnosis.
Innovation Solution
A magnetic resonance imaging method and apparatus that utilize a blade artifact correction sequence (BLADE) with an optimized echo signal evolution curve and variable flip angle train to adjust the flip angle value, controlling T2 attenuation and ensuring image contrast and quality even with increased blade width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blade width is increased to accelerate scanning, then scanning speed is improved, but motion artifacts increase and image quality deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the flip angle throughout the echo train in a variable flip angle TSE sequence. Instead of using a constant flip angle, the flip angle is modified as a function of echo number to compensate for T2 attenuation effects, thereby maintaining image contrast and quality while allowing for accelerated scanning with wider blades.
2Loss of time
If blade width is increased to reduce scanning time, then scanning time is reduced, but image contrast deteriorates due to T2 attenuation
Solution Approach 1:
The patent changes the flip angle parameter dynamically during the echo train to compensate for T2 attenuation. The variable flip angle sequence adjusts the flip angle as a function of echo number, which maintains signal intensity and image contrast even when using wider blades that reduce scanning time.
3Productivity
If conventional TSE sequence is used with fixed flip angle, then sequence simplicity is maintained, but scanning efficiency is low
Solution Approach 1:
The patent introduces dynamics into the TSE sequence by making the flip angle variable rather than fixed. The variable flip angle changes dynamically as a function of echo number within the echo train, allowing the sequence to adapt to T2 attenuation effects and improve scanning efficiency while maintaining reasonable complexity.
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
The method and apparatus enhance scanning speed by up to 52% while maintaining image quality and contrast, effectively reducing motion artifacts and enabling more efficient diagnostic applications.
Implementation Method 1
Magnetic resonance imaging (MRI) is a technique using magnetic resonance phenomena for imaging. The principle of magnetic resonance phenomena mainly involves nuclei containing an odd number of proton(s), for example, hydrogen nuclei widely existing in a human body, the protons thereof are in a spin motion
Implementation Method 2
Nuclei in the external magnetic field are excited by radio frequency (RF) pulses at a specific frequency such that the axes of spin of the nuclei deviate from the positive longitudinal axis or the negative longitudinal axis so as to produce resonance
Implementation Method 3
After stopping transmitting radio frequency pulses, the excited nuclei transmit echo signals gradually release the absorbed energy in the form of electromagnetic waves
Data Source
AI summary
In a magnetic resonance imaging method, a first adjustment parameter is determined for presetting an initial contrast of a magnetic resonance image; a second adjustment parameter is determined for obtaining an optimized contrast of the magnetic resonance image and a specified data acquisition time of a blade artifact correction sequence; an optimized echo signal evolution curve is determined according to the first adjustment parameter and the second adjustment parameter; an actual variable flip angle train is calculated according to the optimized echo signal evolution curve; and the actual variable flip angle train is applied to a two-dimensional fast spin echo sequence, and the blade artifact correction sequence corresponding to the second adjustment parameter is used to acquire magnetic resonance signals and enable the magnetic resonance image to satisfy the optimized contrast.