MRI Navigator Echo Timing Control for Short-TR Body Motion Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MRI technologies face challenges in minimizing the influence of TR extension due to navigator echoes without reducing the time resolution of body motion detection, particularly in short TR imaging, leading to prolonged imaging times and increased burden on subjects.
Innovation Solution
An MRI apparatus and method that automatically control the timing of navigator echo acquisition based on the repetition time (TR) of the pulse sequence, acquiring navigator echoes at a predetermined frequency by adjusting the number of acquisitions according to a set threshold, ensuring time resolution is maintained while minimizing TR extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a navigator echo is acquired separately from the image signal for each TR, then body motion detection precision is improved, but imaging time is prolonged
Solution Approach 1:
The patent combines the navigator echo acquisition with the image signal acquisition process by acquiring both simultaneously during the same TR period, rather than separately. This merging of functions allows body motion detection to be performed without extending the imaging time, as both types of data are collected during the same pulse sequence execution.
Solution Approach 2:
The patent makes the pulse sequence multi-functional by designing it to serve both image acquisition and body motion detection purposes. The same RF pulses and gradient fields are used to generate both the image signal and the navigator echo, allowing one pulse sequence to fulfill multiple functions without requiring additional time.
2Measurement precision
If the navigator echo is acquired for each TR in short TR imaging, then body motion detection capability is improved, but the TR extension influence becomes large
Solution Approach 1:
The patent merges the navigator echo acquisition into the existing image signal acquisition pulse sequence, so that both are obtained during the same TR period. This eliminates the need to extend TR for short TR imaging sequences, maintaining both high imaging efficiency and adequate body motion detection capability.
3Object-affected harmful factors
If the pulse sequence is divided and executed based on camera video detection, then body motion influence is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the body motion detection function from the external camera system and integrates it into the MRI pulse sequence itself through navigator echoes. This eliminates the need for separate camera hardware and its associated complex control systems, reducing overall system complexity while maintaining the ability to detect and compensate for body motion.
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 suppresses TR extension and maintains time resolution for body motion detection, reducing imaging time and operator burden, while allowing for precise body motion correction without manual user settings.
Implementation Method 1
an examination target is disposed in a static magnetic field space, nuclear magnetic resonance is induced within the examination target, nuclear magnetic resonance signals are collected
Implementation Method 2
the gradient magnetic field is applied to a position different from the original gradient magnetic field, and the image reconstruction itself may be difficult
Implementation Method 3
a method of surveilling the motion of the subject using a signal (called a navigator echo) obtained by MRI
Data Source
AI summary
Provided is a technique of minimizing an influence of TR extension due to a navigator echo for body motion detection without reducing a time resolution of body motion detection in imaging using the navigator echo.In a case in which imaging is performed in accordance with a predetermined pulse sequence by using an MRI apparatus, control of generating a navigator echo at a predetermined timing in the pulse sequence is performed, and control of making a timing at which the navigator echo is acquired different between a case in which a repetition time of the pulse sequence is equal to or greater than a preset threshold value and a case in which the repetition time is less than the threshold value is performed.