MRI Double Inversion Recovery Pulse Sequences
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic resonance imaging (MRI) techniques require lengthy scan times to acquire multiple images, particularly for double inversion recovery (DIR) and single inversion recovery (IR) images, which is inefficient in clinical settings.
Innovation Solution
The method involves modifying MRI pulse sequences to utilize multiple magnetization preparation radio frequency pulses within a single scan, allowing for the acquisition of multiple sets of data to produce multiple images efficiently, including both DIR and IR images in a condensed timeframe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate single IR and DIR acquisitions are performed to obtain multiple image types, then image quality and contrast characteristics are improved, but total scan time increases significantly (14-23 minutes)
Solution Approach 1:
The patent combines multiple inversion recovery acquisitions (single IR and DIR) into a single integrated pulse sequence. Multiple magnetization preparation pulses are applied in succession within one scan, allowing simultaneous acquisition of data for different inversion times. This merging approach maintains the ability to produce multiple image types with different contrast characteristics while reducing total scan time from 14-23 minutes to approximately 10-15 minutes.
Solution Approach 2:
The patent applies multiple magnetization preparation pulses in advance within the same scan sequence, preparing different inversion states before data acquisition. By performing the inversion preparation actions preliminarily and systematically, the system can acquire multiple datasets with different inversion times in a single scan, eliminating the need for separate sequential scans.
2Productivity
If multiple magnetization preparation pulses are applied in succession to acquire multiple datasets in one scan, then scan time is reduced (10-15 minutes), but pulse sequence complexity increases
Solution Approach 1:
The patent segments the pulse sequence into distinct, modular components: multiple magnetization preparation pulses applied in succession, followed by data acquisition. Each preparation pulse can be independently configured with different inversion times. This segmentation allows the complex multi-pulse sequence to be managed through systematic, repeatable units, making the increased complexity more manageable and easier to implement.
Solution Approach 2:
The patent employs periodic repetition of the pulse sequence structure, where multiple magnetization preparation pulses are applied in a regular, repeating pattern within each scan. This periodic action creates a systematic framework that reduces the perceived complexity by establishing predictable timing and structure, allowing the system to efficiently cycle through multiple inversion states in a standardized manner.
3Measurement precision
If inversion time is extended to achieve complete magnetization recovery for accurate T1 quantification, then measurement accuracy is improved, but scan time increases
Solution Approach 1:
The patent maintains continuous magnetization recovery processes throughout the scan by applying multiple inversion pulses at different times and acquiring data at multiple inversion times within the same scan. This continuous action allows the system to capture magnetization recovery curves at multiple time points simultaneously, improving T1 quantification accuracy without requiring extended single-timepoint recovery periods. The useful action of measuring recovery continues throughout the scan duration rather than waiting for a single prolonged recovery period.
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 scan time, enabling the acquisition of multiple images with different contrast characteristics in a single scan, improving subject throughput and allowing for accurate T1 quantification and disease-specific image optimization.
Implementation Method 1
When a substance such as human tissue is subjected to a uniform magnetic field, B0, applied along, for example, the z-axis of a Cartesian coordinate system, the individual magnetic moments of the spins in the tissue attempt to align with this magnetic field, B0, but precess about the field in random order at their characteristic Larmor frequency.
Implementation Method 2
If the substance, or tissue, is subjected to a magnetic field, B1, that is applied in the x-y plane and that is near the Larmor frequency of the spins, the net aligned moment, Mz, may be rotated, or 'tipped,' into the x-y plane to produce a net transverse magnetic moment, Mxy.
Implementation Method 3
The contrast of IR techniques is modulated by the T1 (spin-lattice) relaxation time. The TI is selected before the MRI scan begins and determines the image contrast.
Implementation Method 4
This is accomplished by employing magnetic field gradients (Gx, Gy, and Gz) that have the same direction as the polarizing magnetic field, B0, but which have a gradient along the respective x, y, and z axes. By controlling the strength of these gradients during each measurement cycle, the spatial distribution of spin excitation can be controlled and the location of the resulting magnetic resonance signals can be identified.
Implementation Method 5
The resulting set of received magnetic resonance signals are digitized and processed to reconstruct the image using one of many well known reconstruction techniques.
Data Source
AI summary
Described here are a system and method for obtaining multiple different images when performing a single scan of a subject with a magnetic resonance imaging (“MRI”) system. The scan includes the application of two or more magnetization preparation radio frequency (“RF”) pulses, such as inversion recovery (“IR”) pulses. Data is acquired after the application of each magnetization preparation RF pulse, thus allowing the acquisition of multiple different images of the subject in a single scan. Using this approach, the same information that used to require multiple different scans of the subject can be acquired in one single scan, and in less time than would be required to perform the multiple scans.