3D Turbo Spin Echo Imaging Multi-Slab Scanning Efficiency
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Solution Overview
Problem
Current three-dimensional turbo spin echo (3D-TSE) imaging methods are inefficient as they can only scan one slab per repetition time (TR), requiring a lengthy waiting period before scanning the next slab, which reduces imaging efficiency.
Innovation Solution
A method where multiple slabs are scanned within a single TR by applying a first slice selection gradient with the excitation pulse and a second slice selection gradient with the refocusing pulse, allowing simultaneous scanning of other slabs during the waiting period for proton recovery, with specific adjustments for fat-suppressed and non-fat-suppressed imaging and signal correction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If only one slab is scanned per repetition time (TR) in conventional 3D-TSE imaging, then the imaging process is simple to implement, but the imaging efficiency is low due to lengthy waiting periods
Solution Approach 1:
The patent divides the imaging process into multiple independent slab scanning units within a single TR period. Each slab is scanned as a separate segment using selective excitation pulses with different slice selection gradient polarities, allowing parallel processing of multiple slabs instead of sequential scanning, thereby improving imaging efficiency while maintaining manageable sequence complexity through modular design
Solution Approach 2:
The patent employs periodic alternation of slice selection gradient polarities (positive and negative) to enable scanning of multiple slabs within one TR period. By systematically switching gradient directions in a periodic manner, the system can excite and acquire signals from multiple slabs sequentially within the same TR, eliminating idle waiting time while keeping the pulse sequence structure regular and implementable
2Loss of time
If multiple slabs are scanned simultaneously within a TR using slice selection gradients, then imaging time is shortened, but signal strength varies across different slabs requiring correction
Solution Approach 1:
The patent performs preliminary signal correction by identifying and marking slabs with abnormal signal strengths before final image reconstruction. The system detects signal anomalies in advance during the acquisition phase and applies corrective measures in the subsequent processing stage, allowing fast multi-slab scanning while ensuring uniform signal quality across all slabs through pre-emptive quality control
Solution Approach 2:
The patent implements a feedback mechanism where the signal strength of each slab is evaluated and compared against reference values. Based on this feedback, the system automatically identifies slabs requiring correction and applies appropriate signal adjustment algorithms, enabling the system to maintain consistent signal uniformity across multiple slabs scanned within a single TR period
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 significantly shortens imaging time and improves efficiency by enabling the simultaneous scanning of multiple slabs within a TR, while optimizing image quality through adjusted gradient polarities and signal correction methods.
Implementation Method 1
After having applied an external magnetic field, protons in the examined tissues are excited by radio frequency (RF) pulses and they absorb certain energy, which results in their resonance. When the radiation of RF pulses is stopped, the excited protons release the absorbed energy gradually in the form of scan signals.
Implementation Method 2
The external magnetic field includes a main magnetic field and three orthogonal gradient magnetic fields, and in the three orthogonal gradient magnetic fields, the direction which is the same as that of the main magnetic field is usually defined as Z axis direction... the gradient magnetic field along Z axis direction is referred to as the slice selection (SS) gradient
Data Source
AI summary
A three-dimensional turbo spin echo imaging method of applying, within a repetition time TR, N groups of pulses to respectively scan N slabs in succession, with each group including one excitation pulse and more than one refocusing pulse, wherein N is a positive integer greater than 1, is improved by applying a first slice selection gradient at the same time as applying each said excitation pulse, and applying a second slice selection gradient at the same time as applying each said refocusing pulse, and applying a phase encoding gradient after having applied each refocusing pulse, then applying a frequency encoding gradient and acquiring scan signals during the duration of the frequency encoding gradient. An image according to the scan signals is reconstructed.