Parallel MR Data Acquisition Reference Timing
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Solution Overview
Problem
Parallel acquisition techniques in magnetic resonance imaging often result in artifacts during data reconstruction due to differences in contrast and sensitivity between reference and actual measurement data, as well as subject movements, especially when reference data is acquired at different times.
Innovation Solution
Acquiring reference measurement data directly after the actual measurement data using a second pulse sequence, ensuring that the original dataset is completed without magnetization saturation and maintaining close temporal coupling with the original data acquisition to enhance image quality and robustness against subject movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reference measurement data is acquired at different times from actual measurement data, then the data acquisition process can be simplified, but artifacts occur during data reconstruction due to differences in contrast and sensitivity
Solution Approach 1:
The patent applies preliminary action by acquiring reference measurement data immediately after the actual measurement data within the same scanning session. This temporal proximity ensures that both datasets share identical contrast characteristics and sensitivity parameters, eliminating reconstruction artifacts while maintaining efficient parallel acquisition methodology.
2Adaptability or versatility
If reference measurement data is acquired separately, then the parallel acquisition technique can be implemented, but magnetization saturation occurs and image quality deteriorates
Solution Approach 1:
The patent implements preliminary action by acquiring the reference measurement data immediately after the actual measurement data, before any significant magnetization saturation can occur. This temporal sequencing ensures that the reference data is captured while the magnetization state is still optimal, maintaining image quality while enabling parallel acquisition versatility.
Solution Approach 2:
The patent maintains continuity of useful action by acquiring both actual and reference measurement data within the same scanning session without interruption. This continuous acquisition process prevents magnetization saturation and ensures consistent imaging conditions, thereby preserving image quality while implementing parallel acquisition techniques.
3Device complexity
If reference measurement data is acquired at different times, then the acquisition process is simpler, but subject movements affect the accuracy of reconstructed data
Solution Approach 1:
The patent applies preliminary action by acquiring reference measurement data immediately after the actual measurement data, minimizing the time interval between acquisitions. This temporal proximity reduces the impact of subject movements on data accuracy while keeping the acquisition process relatively simple through the use of standard parallel acquisition techniques.
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 improves the quality of MR images by avoiding intensity attenuation and blurring artifacts, while maintaining image contrast and reducing the impact of subject movements, thereby enhancing the robustness and accuracy of the reconstructed data.
Implementation Method 1
In order to trigger nuclear spin resonances, radio-frequency excitation pulses (RF pulses) are radiated into the examination subject, the triggered nuclear spin resonances are measured as echo signals
Implementation Method 2
Rapidly switched magnetic gradient fields are superimposed on the basic magnetic field for the purpose of spatially encoding the measurement data
Implementation Method 3
Another technique is to generate a so-called spin echo SE by application of an RF refocusing pulse RF2 after the application of the RF excitation pulse RF1 after a time TE
Implementation Method 4
This spin echo SE is measured and its amplitude is reduced in accordance with the T2 decay inherent in the measured tissue
Implementation Method 5
a) radiating an RF excitation pulse of a first pulse sequence into a target volume of an examination subject, b) acquiring echo signals generated by the RF excitation pulse of the first pulse sequence and storing those signals in an original measurement dataset, c) acquiring a reference measurement dataset by execution of a second pulse sequence directly after the acquisition of the echo signals generated by the RF excitation pulse of the first pulse sequence
Data Source
AI summary
In a magnetic resonance (MR) apparatus and operating method, a first pulse sequence is executed in order to acquire echo signals from a target volume produced by radiation of a radio-frequency (RF) excitation pulse, thereby obtaining an original measurement dataset. A reference measurement dataset is then acquired by executing another pulse sequence immediately after acquisition of the aforementioned echo signals. These steps are repeated until the original measurement dataset has reached a predetermined degree of completeness that is still incomplete according to the Nyquist criterion. The original measurement dataset is then completed using the reference measurement dataset and a parallel acquisition technique.