Interleaved Flow-Sensitive Dephasing for 3D TSE Blood Flow Suppression
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Solution Overview
Problem
Existing medical imaging techniques, such as 3D T1-weighted turbo-spin echo imaging, face challenges with residual flow artifacts due to insufficient blood flow suppression, which can mimic pathological features and reduce diagnostic accuracy.
Innovation Solution
The implementation of an interleaved flow-sensitive dephasing (iFSD) scheme in the T1-weighted TSE sequence, which includes the addition of a 180-degree RF pulse, unipolar gradient pulses in specific directions, and toggling of gradient polarity to exert a cumulative first-order gradient moment, enhancing blood flow suppression while preserving T1-weighted contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If blood flow suppression techniques are applied, then blood flow artifacts are reduced, but signal reduction and contrast loss occur
Solution Approach 1:
The patent segments the gradient pulses into multiple unipolar gradient pulses applied at different times around the 180-degree RF pulse. This segmentation allows the cumulative first-order gradient moment to be built up progressively, achieving effective blood flow suppression while minimizing signal loss and contrast degradation that would occur with a single large gradient pulse.
Solution Approach 2:
The patent employs periodic application of unipolar gradient pulses at specific intervals around the 180-degree RF pulse. The gradient pulses are applied periodically in a controlled manner, with polarity toggling between successive TR cycles, creating a cumulative effect that suppresses blood flow artifacts while preserving signal intensity and T1-weighted contrast.
2Object-affected harmful factors
If flow-sensitive dephasing is enhanced, then blood flow suppression is improved, but T1-weighted contrast is lost
Solution Approach 1:
The patent applies local quality by making the gradient pulse polarity dependent on the specific TR cycle number. The polarity of the unipolar gradient pulses is toggled for different TR cycles, creating a localized effect that accumulates the first-order gradient moment selectively. This localized approach ensures blood flow suppression while preserving T1-weighted contrast by avoiding uniform signal suppression.
Solution Approach 2:
The patent changes the parameter of gradient pulse polarity over time, toggling the polarity between successive TR cycles. This parameter change creates a cumulative first-order gradient moment that enhances blood flow suppression while maintaining T1-weighted contrast. The dynamic adjustment of gradient parameters allows selective suppression of flow artifacts without sacrificing contrast.
3Object-affected harmful factors
If gradient pulses are applied to suppress blood flow, then flow artifacts are reduced, but signal-to-noise ratio is reduced
Solution Approach 1:
The patent applies preliminary action by preparing the cumulative first-order gradient moment through multiple small unipolar gradient pulses applied before and after the 180-degree RF pulse. This preliminary buildup of gradient moment achieves effective blood flow suppression while minimizing the signal-to-noise ratio penalty compared to applying a single large gradient pulse, as the cumulative effect is achieved through multiple smaller, more tolerable steps.
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 iFSD scheme effectively suppresses blood flow artifacts, maintains T1-weighted contrast, and reduces signal-to-noise ratio penalties, thereby improving the diagnostic performance of 3D turbo spin-echo imaging.
Implementation Method 1
generating, via a sequence controller and through one or more radio frequency coils, a 90-degree excitation radio frequency pulse
Implementation Method 2
generating, via the sequence controller and through the one or more gradient amplifiers, a first pair of unipolar gradient pulses
Implementation Method 3
performing a step of generating, via the sequence controller and through the one or more radio frequency coils, a refocusing radio frequency pulse
Implementation Method 4
toggling, via the sequence controller, at least one of a first polarity of the first gradient amplifier and a second polarity of the second gradient amplifier at each time of repetition
Data Source
AI summary
Systems, computer-readable medium, methods and apparatus, and/or devices are provided interleaved flow-sensitive dephasing. The disclosed dephasing enhances flow-suppression capability that makes 3D T1-weighted turbo-spin echo (TSE) imaging useful for brain metastasis detection and intracranial vessel wall and venous sinus imaging. The disclosed mechanisms suppress residual flow artifacts mimicking pathological features, while maintaining signal quality and T-1 weighted contrast, maintaining the diagnostic performance of 3D TSE.