Parallel MRI Calibration During Contrast Transit
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Solution Overview
Problem
Current parallel imaging techniques in MRI require significant overhead time for calibration data acquisition, which can extend the overall scan duration and compromise image quality, especially in procedures like contrast-enhanced magnetic resonance angiography (CE-MRA), due to the need for separate calibration and image acquisition phases and precise patient positioning.
Innovation Solution
Acquiring calibration data during the contrast agent's transit from injection to the targeted arterial vasculature, allowing for streamlined preparation and eliminating delays associated with pulse sequence downloads, enabling all data acquisition to be done within a single breathhold and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate calibration and image acquisition phases are used in parallel imaging, then calibration data can be acquired with adequate quality, but the overall scan duration is extended
Solution Approach 1:
The patent merges the calibration data acquisition with the contrast agent transit phase by acquiring calibration data during the time the contrast agent is traveling through the vasculature. This eliminates the need for a separate calibration phase before image acquisition, thereby reducing total scan duration while maintaining calibration data quality through proper timing and positioning protocols.
Solution Approach 2:
The patent performs calibration data acquisition in advance during the contrast transit phase, before the actual image acquisition begins. By preparing the calibration data during the naturally occurring contrast agent transit time, the system eliminates delays associated with pulse sequence downloads and positioning adjustments that would otherwise occur between separate calibration and imaging phases.
2Manufacturing precision
If calibration data is acquired before contrast agent injection, then adequate positioning can be achieved, but the scan time increases and patient positioning must be maintained perfectly
Solution Approach 1:
The patent maintains continuous useful action by acquiring calibration data during the contrast agent transit phase rather than requiring a separate positioning and calibration phase before contrast injection. The patient remains in position throughout, and the calibration acquisition occurs continuously during the naturally occurring contrast transit time, eliminating idle time and reducing the risk of positioning errors.
3Productivity
If parallel imaging acceleration is applied, then acquisition time is reduced, but calibration overhead time remains significant
Solution Approach 1:
The patent combines the calibration data acquisition with the contrast agent transit phase, merging two previously separate processes into one continuous acquisition window. This eliminates the calibration overhead time that would otherwise occur before the accelerated parallel imaging acquisition, allowing the full benefit of parallel imaging acceleration to be realized without the burden of separate calibration delays.
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 reduces the overall scan time and enhances image quality by integrating calibration data acquisition into the contrast transit phase, eliminating the need for separate calibration and image acquisition phases, thus improving the efficiency and speed of parallel imaging acquisitions.
Implementation Method 1
magnetic resonance imaging ('MRI') techniques are used to image blood vessels
Implementation Method 2
a magnetic gradient system including a plurality of magnetic gradient coils configured to apply at least one magnetic gradient field to the polarizing magnetic field
Implementation Method 3
a radio frequency (RF) system configured to apply an RF field to the subject and to receive magnetic resonance signals therefrom
Implementation Method 4
The presence of the contrast agent in the blood causes the net relaxation time of the blood to be altered from its unenhanced value
Data Source
AI summary
A system and method for performing parallel magnetic resonance angiography includes controlling operation of a magnetic gradient system and an RF system to perform a calibration data pulse sequence to begin acquiring calibration data for use in a parallel imaging reconstruction process after receiving an indication that the subject has received a dose of a contrast agent. The acquisition of the calibration data is discontinued before the contrast agent reaches a peak concentration within a region of interest (ROI) of the subject and operation of the magnetic gradient system and RF system is controlled to perform an imaging pulse sequence in accordance with a parallel imaging acquisition to begin acquiring image data from the ROI. The image data is reconstructed into an image of the ROI using the calibration data.