Magnetic Resonance Temperature Mapping via Multi-Echo Projections
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Solution Overview
Problem
Current magnetic resonance tomography methods are inefficient in quickly determining temperature changes, particularly in three-dimensional acquisitions, due to limitations in measurement time caused by specific absorption rate (SAR) regulations and the risk of tissue damage from non-homogeneous field distributions, as well as the challenge of detecting transient temperature peaks.
Innovation Solution
A method utilizing a multi-echo sequence to acquire and store projections of magnetic resonance signals across non-parallel m-dimensional spaces, allowing for the quick localization of temperature changes by calculating differences across these spaces, thereby reducing measurement time and minimizing artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic resonance tomography with diffusion-sensitive imaging is used to monitor temperature changes, then temperature mapping can be achieved, but the measurement time is too long to detect transient temperature peaks
Solution Approach 1:
The patent segments the three-dimensional temperature mapping problem into multiple two-dimensional projection measurements taken at different angles. By acquiring projections at multiple angular positions and reconstructing the three-dimensional temperature distribution from these segmented views, the method achieves comprehensive temperature monitoring while reducing the time required for each individual measurement plane
Solution Approach 2:
The patent transitions from direct three-dimensional temperature mapping to a dimensional reduction approach by measuring two-dimensional projections at multiple angles. This dimensional change allows the system to capture three-dimensional temperature information through a series of two-dimensional measurements, significantly reducing the time required for each measurement while maintaining spatial resolution
2Measurement precision
If stronger basic magnetic fields (3 T or more) are used to increase radio-frequency excitation frequency, then measurement sensitivity improves, but specific absorption rate increases quadratically causing local overheating and tissue damage
Solution Approach 1:
The patent changes the measurement parameter from direct three-dimensional temperature mapping to angular projection measurements. This parameter change allows the use of lower radio-frequency power settings since each projection measurement requires less energy, thereby reducing the specific absorption rate and preventing local overheating while still achieving accurate temperature monitoring through multi-angle reconstruction
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
Enables the rapid detection of temperature changes and localization of transient peaks, reducing the risk of tissue damage by minimizing exposure to radio-frequency pulses and efficiently monitoring thermal treatments.
Implementation Method 1
excitation of nuclear spins in a sample volume by radiating a radio-frequency pulse in a static magnetic field
Implementation Method 2
The nuclear spins are aligned in an external basic magnetic field and precess with the Larmor frequency around the axis of the alignment in the magnetic field, after excitation by an alternating external electromagnetic (radio-frequency) field
Implementation Method 3
The initial amplitude, the phase coherence of this precession, and the decay of the excitation, change depending on the temperature of a sample in which the atomic nuclei are located
Data Source
AI summary
In a method and apparatus to quickly determine regions of modified temperature in a sample volume by magnetic resonance tomography using a multi-echo sequence, one or more one-dimensional or two-dimensional images of regions of modified temperature are respectively determined.