Simultaneous Multi-Slice TSE Imaging with Shared Echo Train
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Solution Overview
Problem
Conventional turbo spin echo (TSE) sequences in magnetic resonance imaging face limitations in selecting echo times due to the need for separate readout blocks, leading to restricted freedom in echo time selection, differing modulation transfer functions, and resulting in inaccurate image reconstructions and reduced spatial resolution.
Innovation Solution
Implementing a simultaneous multi-slice (SMS) data acquisition technique where slices are excited at different times, sharing a readout echo train, and using single-band and multi-band pulses within one echo train to acquire datasets with different contrasts, allowing for more flexible echo times and identical modulation transfer functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate readout blocks are used for different contrasts in conventional TSE sequences, then different echo times can be achieved, but the freedom in echo time selection is restricted and modulation transfer functions differ
Solution Approach 1:
The patent combines multiple contrasts with different echo times into a single shared readout echo train using simultaneous multi-slice acquisition. Instead of using separate readout blocks for each contrast, the invention merges them into one unified echo train where different slices are excited at different times within the same train, achieving both flexible echo time selection and consistent modulation transfer functions.
Solution Approach 2:
The patent introduces the time dimension by exciting different slices at different times within a single echo train. This temporal separation allows multiple contrasts to be acquired in one echo train while maintaining consistent spatial encoding and modulation transfer functions, resolving the contradiction between echo time flexibility and reconstruction accuracy.
2Adaptability or versatility
If separate readout blocks are used for different contrasts, then different echo times can be selected, but total echo train length increases
Solution Approach 1:
The patent merges multiple contrasts into a single shared echo train, eliminating the need for separate readout blocks. This consolidation reduces the total echo train length while maintaining the ability to select different echo times for different contrasts through temporal separation of slice excitations.
Solution Approach 2:
The patent maintains continuous useful action by using a single uninterrupted echo train to acquire all contrasts. Instead of having gaps between separate readout blocks, the continuous echo train efficiently acquires data for multiple contrasts without interruption, reducing total acquisition time.
3Adaptability or versatility
If separate readout blocks are used for different contrasts, then different echo times can be achieved, but Gibbs artifacts increase
Solution Approach 1:
The patent merges all contrasts into a single echo train with consistent k-space sampling and modulation transfer functions. This unified approach eliminates the discontinuities between separate readout blocks that cause Gibbs artifacts, while still allowing flexible echo time selection through temporal separation of slice excitations.
4Adaptability or versatility
If separate readout blocks are used for different contrasts, then different echo times can be selected, but modulation transfer functions differ
Solution Approach 1:
The patent merges multiple contrasts into a single echo train that uses consistent k-space sampling and modulation transfer functions for all contrasts. By eliminating separate readout blocks, the invention ensures that all contrasts share the same modulation transfer function, providing stability and consistency while maintaining echo time flexibility.
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 a shorter total echo train length, identical blurring effects, and reduced Gibbs artifacts, enabling more flexible echo time selection and improved image accuracy by maintaining consistent image reconstruction properties across contrasts.
Implementation Method 1
the examination object (a patient, in the case of medical magnetic resonance imaging) is exposed to a strong and constant basic magnetic field, by the operation of a basic field magnet of an MR scanner
Implementation Method 2
The magnetic resonance signals are produced by the radiation of radio-frequency (RF) pulses from an RF radiator, such as one or more antennas, in the MR scanner. These RF pulses excite nuclear spins in the examination object
Implementation Method 3
The MR scanner also has a gradient coil arrangement that is operated in order to activate gradient fields that spatially encode the magnetic resonance signals
Implementation Method 4
As the nuclear spins relax, while returning to alignment in the basic magnetic field, they emit MR signals (which are also RF signals)
Implementation Method 5
multiple refocusing RF pulses are radiated that continually refocus the decaying magnetization, and an individual echo signal is respectively acquired after each refocusing pulse
Data Source
AI summary
In a method and apparatus for acquiring magnetic resonance (MR) raw data, an MR data acquisition scanner is operated to execute a turbo spin echo (TSE) or a turbo gradient spin echo (TGSE) sequence wherein nuclear spins are excited in multiple slices of the examination object simultaneously by radiating at least one radio-frequency (RF) pulse from an RF radiator of the MR data acquisition scanner, thereby causing the excited nuclear spins in said multiple slices to produce an echo train. A multi-band refocusing pulse is radiated that refocuses nuclear spins in at least one of said multiple slices that follows a first of the multiple slices, and readout gradients are activated to acquire MR signals, with respectively different contrasts, at respectively different readout times of the echo train. The read out MR signals are entered into an electronic memory organized as k-space.