Asymmetric Gradient Echo for Fat Suppression
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Solution Overview
Problem
Current MR imaging systems require a long repetition time to achieve uniform fat suppression, leading to extended scan times and breath-hold periods, which can be problematic for patients, especially those who are critically ill.
Innovation Solution
A system employing a three-dimensional spoiled gradient recalled echo pulse sequence with reversed echo asymmetry during data acquisition, utilizing an asymmetric read-out gradient magnetic field to reduce RF pulse repetition time and total acquisition time, allowing for faster image acquisition while maintaining effective fat suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a long repetition time is used to achieve uniform fat suppression, then fat suppression uniformity is improved, but scan time increases
Solution Approach 1:
The patent applies asymmetric read-out gradient magnetic field moments where the gradient moment area is intentionally made non-symmetric about the echo time. This asymmetric gradient waveform allows the system to achieve uniform fat suppression at opposed phase echo time while reducing the total acquisition time, thereby resolving the contradiction between fat suppression uniformity and scan time.
Solution Approach 2:
The patent modifies the gradient magnetic field parameters by using asymmetric moment distribution instead of traditional symmetric or balanced gradient waveforms. By changing the gradient moment parameters (making them asymmetric and optimizing the read-out timing), the system achieves both uniform fat suppression and reduced scan time simultaneously.
2Manufacturing precision
If a long repetition time is used for fat suppression, then fat suppression quality is improved, but breath-hold time increases
Solution Approach 1:
The asymmetric read-out gradient magnetic field moments enable the system to complete the fat suppression requirement in a shorter time window. By optimizing the asymmetric gradient waveform, the breath-hold time is reduced while maintaining adequate fat suppression quality, making the procedure more tolerable for patients.
3Productivity
If faster image acquisition is implemented, then scan time is reduced, but fat suppression uniformity may deteriorate
Solution Approach 1:
The patent demonstrates that asymmetric gradient waveforms can achieve both fast acquisition and uniform fat suppression. The asymmetric moment distribution is specifically designed to provide the necessary phase information for fat suppression while reducing the total acquisition time, thereby achieving high productivity without sacrificing fat suppression uniformity.
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 the breath-hold time and total scan time, reducing the susceptibility to motion and breathing artifacts, and enables higher spatial resolution during MR imaging, particularly beneficial for critically ill patients.
Implementation Method 1
A read-out gradient magnetic field generator generates an asymmetric read-out gradient magnetic field having an asymmetric moment distribution, such that the RF echo pulse peak occurs after the readout gradient mid-point
Implementation Method 2
An RF pulse generator generates an RF excitation pulse sequence having a pulse repetition interval. The RF echo pulse peak is received in response to a generated RF excitation pulse
Data Source
AI summary
A system uses a three-dimensional spoiled gradient recalled echo sequence for fat suppression with reduced total acquisition time suitable for acquiring image data under breath-hold conditions using a reversed asymmetry during data acquisition on an opposed phase echo. A system reduces RF pulse repetition time in an MR imaging pulse sequence in an MR imaging device. The system includes an RF pulse generator for generating an RF excitation pulse sequence having a pulse repetition interval. A read-out gradient magnetic field generator generates an asymmetric read-out gradient magnetic field having a readout gradient mid-point occurring prior to an RF echo pulse peak. The RF echo pulse peak is received in response to a generated RF excitation pulse.