MRI Inversion Pulse Timing Control for Multi-Contrast Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MRI techniques face limitations in reducing imaging time when acquiring multiple contrast images, as the waiting time between inversion recovery pulses is not fully utilized, leading to inefficiencies in multi-slice imaging.
Innovation Solution
The technique involves controlling slice positions to minimize the influence of adjacent RF pulses and utilizing the interval between inversion recovery pulses to execute different imaging sequences for each slice, allowing for simultaneous acquisition of multiple contrast images, including FLAIR and other weighted images, by shifting the application timing of the inversion pulse across multiple slices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multi-slice imaging is performed by successively applying IR pulses to different slices, then the waiting time TI can be utilized more effectively, but the imaging time is extended due to the required interval between IR pulses for signal measurement
Solution Approach 1:
The imaging process is segmented into multiple groups where different slice groups are imaged at different times. Specifically, first slice groups are imaged before inversion pulses are applied to second slice groups, allowing parallel processing and utilization of waiting time without extending total imaging time
Solution Approach 2:
Imaging of first slice groups is performed preliminarily before applying IR pulses to second slice groups. This preliminary action allows the system to prepare and acquire images during the waiting time period, maximizing time utilization
2Productivity
If multiple contrast images are acquired simultaneously using FSE sequence, then imaging time is reduced, but the waiting time TI of IR sequence is not fully utilized
Solution Approach 1:
The system maintains continuous useful action by performing imaging sequences during the waiting time TI period. Instead of leaving the IR sequence waiting time idle, another imaging sequence is executed continuously, ensuring no time is wasted
Solution Approach 2:
The imaging system is designed to perform multiple functions simultaneously: acquiring FLAIR images from one slice group while acquiring other contrast images from different slice groups during the same time period, maximizing productivity
3Duration of action of moving object
If IR pulses are applied to adjacent slices at the same time, then imaging time is reduced, but image quality deteriorates due to mutual influence of RF pulses
Solution Approach 1:
Slices are segmented into different groups (first slice groups and second slice groups) that are imaged at different times. This segmentation prevents mutual interference between RF pulses while still allowing efficient parallel processing within each group
Solution Approach 2:
The imaging is performed in periodic cycles where first slice groups are imaged, then IR pulses are applied to second slice groups, followed by imaging of second slice groups. This periodic action pattern ensures sufficient time separation to avoid RF pulse interference
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 the overall imaging time by effectively utilizing the waiting time between pulses, enabling the acquisition of multiple contrast images with improved efficiency and image quality by minimizing the impact of adjacent IR pulses.
Implementation Method 1
an imaging unit that collects a nuclear magnetic resonance signal generated by an examination object, and acquires an image of the examination object
Implementation Method 2
a high frequency pulse (IR pulse) that inverses a spin is applied, by using a difference in longitudinal relaxation time between a spin of water and a spin of fat
Data Source
AI summary
To provide an MRI apparatus that acquires a plurality of contrast images including an FLAIR image in the shortest imaging time. An imaging controller of the MRI apparatus includes, as a prescribed pulse sequence, an IR (inversion recovery) sequence that includes application of an inversion pulse and a signal acquisition sequence to collect a signal after an inversion time has elapsed from the application of the inversion pulse, and acquires images in a first slice group, and an imaging sequence that is inserted into an inversion pulse of the IR sequence at a single time and an inversion pulse of the IR sequence at the next time, and acquires images in a second slice group different from the first slice group that are images having different contrasts from that of the IR sequence.