MRI Pulse Sequence Segmentation for Motion Artifact Suppression
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face challenges in suppressing motion artifacts caused by physiological motions like respiratory and cardiac movements, leading to reduced image quality.
Innovation Solution
A system and method that utilize a pulse sequence including a steady-state sequence and an acquisition sequence, where the steady-state sequence is free of phase encoding and readout gradients to minimize noise, and the acquisition sequence includes dephasing gradients to correct for magnetic field non-uniformity, allowing for improved image acquisition during physiological cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional MRI pulse sequence is used to acquire MR data, then image reconstruction can be performed, but motion artifacts are introduced due to physiological motions during the scan
Solution Approach 1:
The pulse sequence is segmented into multiple sub-sequences (e.g., spin echo sub-sequence and gradient echo sub-sequence) with different gradient configurations. This segmentation allows selective application of dephasing gradients during specific phases to suppress motion artifacts while maintaining image quality
Solution Approach 2:
Dephasing gradients are applied before the actual data acquisition to pre-compensate for motion effects. By introducing these gradients in advance during the pulse sequence, the system counteracts physiological motions before they can degrade image quality
2Measurement precision
If dephasing gradients are applied to correct magnetic field non-uniformity, then image quality improves, but noise is introduced during the scan
Solution Approach 1:
Different gradient configurations are applied to different sub-sequences: the spin echo sub-sequence uses strong dephasing gradients to suppress motion artifacts, while the gradient echo sub-sequence uses weaker gradients to minimize noise. This local differentiation optimizes the balance between artifact suppression and noise reduction
Solution Approach 2:
The pulse sequence employs periodic alternation between different gradient configurations in a cyclic manner. By periodically switching between dephasing gradient applications and relaxation periods, the system achieves motion suppression while allowing noise to decay between cycles
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 effectively reduces noise and stabilizes physiological motion, enhancing the accuracy of image acquisition and reducing motion artifacts in MRI images.
Implementation Method 1
the acquisition sequence includes a first dephasing gradient. The steady-state sequence may include a second dephasing gradient
Implementation Method 2
Magnetic resonance imaging (MRI) is a widely used medical technique which may produce images of an object by exploiting a powerful magnetic field and radio frequency (RF) techniques
Data Source
AI summary
A method for magnetic resonance imaging (MRI) may include cause, based on a pulse sequence, a magnetic resonance (MR) scanner to perform a scan on an object. The pulse sequence may include a steady-state sequence and an acquisition sequence that is different from the steady-state sequence. The steady-state sequence may correspond to a steady-state phase of the scan in which no MR data is acquired. The acquisition sequence may correspond to an acquisition phase of the scan in which MR data of the object is acquired. The method may also include generating one or more images of the object based on the MR data.