Simultaneous Multi-Slice MRI Navigator for Real-Time Motion Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic resonance imaging (MRI) is hindered by movement artifacts due to patient movement during scans, which can degrade image quality, and existing motion correction methods are either retrospective or have limitations in real-time adaptation.
Innovation Solution
A method utilizing simultaneous multi-slice techniques for both reference and navigator measurements to quickly acquire movement information, allowing for dynamic adjustment of imaging parameters during the MRI sequence, enabling real-time motion compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional navigator measurements are performed sequentially slice by slice, then measurement precision is maintained, but measurement time increases and productivity decreases
Solution Approach 1:
The examination object is divided into multiple slices that are measured simultaneously rather than sequentially. The navigator volume is segmented into multiple slices, each excited by its own RF pulse, allowing parallel acquisition of data from all slices at once, thereby dramatically reducing measurement time while maintaining precision.
Solution Approach 2:
The patent transitions from one-dimensional sequential slice acquisition to three-dimensional simultaneous multi-slice acquisition. By adding the dimension of parallel processing across multiple slices, the system achieves faster navigator volume acquisition without compromising measurement precision.
2Productivity
If simultaneous multi-slice technique is used for navigator measurements, then productivity and speed are improved, but device complexity increases
Solution Approach 1:
The simultaneous multi-slice technique serves multiple functions: it accelerates navigator volume acquisition, enables real-time motion detection, and provides comprehensive coverage of the examination object. This multi-functional approach justifies the increased system complexity by delivering multiple benefits from a single technical implementation.
Solution Approach 2:
The system implements real-time feedback by continuously acquiring navigator volumes using simultaneous multi-slice technique, detecting motion artifacts, and adjusting imaging parameters dynamically. This feedback loop manages system complexity by automating motion correction, reducing the need for manual intervention and complex post-processing.
3Measurement precision
If motion correction is performed retrospectively after data acquisition, then measurement precision is maintained, but loss of time occurs and adaptability is reduced
Solution Approach 1:
The system performs preliminary motion detection and correction actions during the acquisition process itself rather than after completion. Navigator volumes are continuously measured to detect motion early, allowing real-time adjustment of imaging parameters before the scan completes, thereby maintaining precision while enabling adaptability.
Solution Approach 2:
Real-time feedback from continuous navigator measurements enables dynamic adjustment of imaging parameters during acquisition. The system monitors motion artifacts as they occur and immediately corrects them, combining measurement precision with real-time adaptability through a closed-loop control mechanism.
4Measurement precision
If longer acquisition duration is used for navigator volume, then measurement precision is improved, but productivity decreases and loss of time occurs
Solution Approach 1:
The navigator volume is segmented into multiple slices acquired simultaneously, reducing the total acquisition time while maintaining measurement precision. Each slice contributes to the overall motion detection accuracy, and their parallel acquisition eliminates the time penalty of sequential scanning.
Solution Approach 2:
The simultaneous multi-slice technique enables continuous useful action by acquiring all slice data in one go rather than intermittently. This continuous acquisition maintains measurement precision through comprehensive sampling while maximizing productivity by eliminating idle time between slice acquisitions.
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 reduces movement artifacts by enabling rapid and accurate detection of patient movement, improving image quality through real-time adaptation of imaging parameters, thus enhancing the quality of MRI data acquisition.
Implementation Method 1
the patient is subjected to a relatively high basic magnetic field, for example 1.5 or 3 or 7 tesla with the use of a main magnet
Implementation Method 2
Radio-frequency pulses, for example excitation pulses, are then emitted via a radio-frequency antenna arrangement by suitable antennas, causing the nuclear spins of certain atoms resonantly excited by these radio-frequency pulses to be tilted
Implementation Method 3
During the relaxation of the nuclear spins, radio-frequency signals, so-called magnetic-resonance signals are emitted and are received by suitable radio-frequency antennas
Data Source
AI summary
In a magnetic resonance apparatus and operating method therefor, movement compensation during raw data acquisition is accomplished by operating the data acquisition scanner to acquire data from a reference navigator volume at a first point in time, using a simultaneous multi-slice technique with a first acceleration factor and a first number of first slice groups, and to acquire data from a navigator volume at a second point in time, also using a simultaneous multi-slice technique, but with a second acceleration factor and a second number of second slice groups, with the first and second acceleration factors being equal. Movement information is determined from the reference navigator volume and the navigator volume, describing movement of the patient occurring between the first and second points in time. Data acquisition parameters of the scanner are set after the second point in time, dependent on the movement information, for acquiring further magnetic resonance data.