MRI Apparatus k-Space Acquisition Timing
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Solution Overview
Problem
The quality of images obtained by combining the Time-SLIP method with the Stack of Stars method for Magnetic Resonance Angiography can be degraded due to the order of data acquisitions, particularly when acquisitions are performed at times distant from the null point, leading to insufficient signal suppression and degraded data quality.
Innovation Solution
A magnetic resonance imaging apparatus with sequence control circuitry that applies a pre-pulse inverting longitudinal magnetization, acquiring k-space data by performing three-dimensional acquisitions using the Stack of Stars method, where radial acquisitions are done on the kx-ky plane and Cartesian acquisitions in the kz direction, with specific timing adjustments to ensure data acquisition near the null point, thereby improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data acquisition is performed using the Stack of Stars method with simple three-dimensional acquisitions, then the acquisition process can be completed, but the image quality is degraded due to insufficient signal suppression when acquisitions are performed at times distant from the null point
Solution Approach 1:
The patent segments the three-dimensional k-space acquisition into two distinct components: radial acquisition in the kx-ky plane and Cartesian acquisition in the kz direction. This segmentation allows independent optimization of timing for each acquisition direction, ensuring that central k-space data is acquired at the null point for optimal signal suppression while peripheral data can be acquired with more flexible timing.
Solution Approach 2:
The patent applies preliminary timing adjustments to the data acquisition process by calculating and implementing specific timing offsets for different k-space lines. The central k-space lines are scheduled to be acquired at the predetermined time point when longitudinal magnetization reaches the null point, while peripheral lines use calculated timing adjustments to compensate for their different spatial positions, ensuring all data contributes optimally to image quality.
2Productivity
If data acquisition is performed away from the null point, then the acquisition time can be reduced, but the signal suppression becomes insufficient and data quality is degraded
Solution Approach 1:
The patent applies local quality optimization by treating different regions of k-space differently. Central k-space lines (which contain low-frequency information critical for overall image contrast) are acquired precisely at the null point for maximum signal suppression. Peripheral k-space lines (containing high-frequency detail information) use calculated timing adjustments that balance acquisition speed with adequate signal suppression, optimizing the trade-off locally for each region.
Solution Approach 2:
The patent dynamically adjusts the acquisition timing parameter based on the specific k-space line being acquired. By calculating timing offsets relative to the central k-space acquisition time and applying them to peripheral lines, the system changes the temporal parameter to optimize both signal suppression and acquisition efficiency for different spatial frequencies simultaneously.
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 enhances image quality by ensuring that acquisitions are performed when longitudinal magnetization reaches the null point, specifically for central k-space data, reducing signal suppression issues and improving the overall quality of acquired images.
Implementation Method 1
a pre-pulse (an inversion pulse) that inverts longitudinal magnetization from a positive value to a negative value
Implementation Method 2
k-space data is acquired by performing three-dimensional acquisitions in which a radial acquisition is performed on a kx-ky plane, and a Cartesian acquisition is performed in a kz direction
Data Source
AI summary
A magnetic resonance imaging apparatus according to an embodiment includes sequence controlling circuitry. The sequence controlling circuitry applies a pre-pulse that inverts longitudinal magnetization from a positive value to a negative value and is configured, when a predetermined time period has elapsed, to acquire k-space data by performing three-dimensional acquisitions in which a radial acquisition is performed on a kx-ky plane and a Cartesian acquisition is performed in a kz direction.