bSSFP MRI Continuous Spin Labeling for Fluid Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic resonance imaging methods, such as Time-SLIP and tagging methods, face limitations in labeling duration, making it difficult to visualize continuous or involuntary movements of observation targets like blood and cerebrospinal fluid due to non-constant label appearance.
Innovation Solution
The implementation of a balanced steady-state free precession (bSSFP) sequence with a spin labeling gradient magnetic field applied within each repetition time interval, generating continuous spin labels to maintain longitudinal and transverse magnetization, allowing for the visualization of continuous movements by maintaining label visibility over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If traditional labeling methods (Time-SLIP or tagging) are used, then imaging can be performed after labeling, but the labeling duration is limited causing non-constant label appearance
Solution Approach 1:
The patent applies continuous spin labeling throughout the imaging process rather than discrete pre-labeling. The spin labeling gradient magnetic field is continuously applied during the bSSFP sequence, maintaining constant label appearance and enabling reliable visualization of continuous or involuntary movements without the duration limitations of traditional methods.
Solution Approach 2:
The patent changes the magnetic field parameters by applying a spin labeling gradient magnetic field during the imaging sequence. This modifies the Larmor frequency of spins in a controlled manner, creating continuous labels that persist throughout the imaging process, thereby extending the effective labeling duration and maintaining label appearance consistency.
2Productivity
If labeling is performed before readout, then imaging can be executed, but continuous movement visualization is difficult due to label decay
Solution Approach 1:
The patent performs spin labeling continuously during the bSSFP imaging sequence rather than before it. This continuous labeling approach ensures that labels remain visible throughout the entire imaging process, enabling both rapid imaging and continuous movement visualization without the compromise between imaging speed and label durability.
Solution Approach 2:
The patent prepares spin labels continuously throughout the imaging process rather than in advance. This ongoing preparation ensures that fresh labels are always available for visualization, maintaining label visibility duration equal to the imaging duration while preserving high imaging speed through efficient continuous labeling.
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 continuous visualization of movement by maintaining label visibility, allowing for the accurate depiction of fluid and organ movement without the limitations of traditional labeling methods, effectively addressing the challenge of non-constant label appearance.
Implementation Method 1
performing a balanced steady-state free precession (bSSFP) sequence, which repeatedly applies an excitation radio frequency (RF) pulse to a subject at intervals of a repetition time and applies gradient magnetic field pulses balanced such that a time integral becomes zero within each interval of the repetition time, while further applying a spin labeling gradient magnetic field for generating one or more continuous spin labels within each interval of the repetition time
Data Source
AI summary
A magnetic resonance imaging method according to an embodiment includes performing a balanced SSFP sequence, repeatedly applies an excitation RF pulse to a subject at intervals of a repetition time and applies gradient magnetic field pulses balanced such that a time integral becomes zero within each interval of the repetition time, while further applying a spin labeling gradient magnetic field for generating one or more continuous spin labels within each interval of the repetition time.