Echo-Based Single Point Imaging for High-Resolution Oxygen Mapping
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Solution Overview
Problem
Current tissue imaging methods, such as spin echo Fourier transform and multi-gradient single point imaging, face challenges in achieving high spatial resolution and accurate oxymetric information simultaneously, with limitations due to spin probe line width, magnetic susceptibility, and field inhomogeneity.
Innovation Solution
The Echo-Based Single Point Imaging (ESPI) method combines electron spin-echo imaging with single point imaging techniques, using a 90°-180° pulse sequence and pure phase encoding to generate high-resolution images that are unaffected by spin probe line width and magnetic field inhomogeneity, allowing for accurate T2-weighted oxygen mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spin echo Fourier transform imaging is used, then oxymetric information is obtained, but spatial resolution is insufficient
Solution Approach 1:
The patent merges spin echo imaging with single point imaging techniques to create a hybrid method that achieves both high spatial resolution and accurate oxymetric information. The spin echo pulse sequence provides T2-weighted contrast for oxygen quantification, while single point imaging with pure phase encoding delivers superior spatial resolution.
Solution Approach 2:
The patent changes the encoding approach from frequency encoding to pure phase encoding, and modifies the pulse sequence to use spin echo with specific timing parameters. This allows the method to achieve high spatial resolution while maintaining accurate T2-weighted oxymetric measurements through controlled echo times.
2Manufacturing precision
If multi-gradient single point imaging is used, then spatial resolution is superior, but oxymetric accuracy requires careful calibration
Solution Approach 1:
The patent makes the system self-calibrating by using the spin echo sequence to inherently provide T2-weighted contrast that is directly related to oxygen concentration. The method eliminates the need for external reference standards by using the intrinsic relaxation properties of the spin probe, with the echo time parameters controlling the oxygen sensitivity.
Solution Approach 2:
The patent changes the imaging approach to use spin echo with pure phase encoding and specific gradient timing, which provides both high spatial resolution and inherent T2-weighting for oxygen quantification without requiring additional calibration procedures.
3Ease of manufacture
If conventional imaging methods are used, then imaging is feasible, but results are affected by magnetic susceptibility and field inhomogeneity
Solution Approach 1:
The patent converts the harmful effects of magnetic susceptibility and field inhomogeneity into beneficial T2-weighted contrast. The spin echo sequence with controlled echo times transforms these disturbances into the desired oxygen-sensitive contrast mechanism, where the dephasing and rephasing processes highlight oxygen concentration differences.
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
ESPI provides superior spatial resolution and accurate quantitative oxygen imaging, unaffected by system-specific factors, enabling reliable in vivo tissue oxygen mapping with high-resolution images and precise oxygen concentration measurements.
Implementation Method 1
The second pulse refocuses any line broadening brought about by the gradient-induced T2* and the intrinsic magnetic susceptibility of the subject
Implementation Method 2
an echo is received in which the echo peak height is attenuated by spin-spin relaxation
Implementation Method 3
Electron Paramagnetic Resonance (EPR) is a spectroscopic technique that is analogous to Nuclear Magnetic Resonance (NMR). EPR spectroscopy detects species with unpaired electrons such as transition metal ions and free radicals
Implementation Method 4
Fourier transform of the echo measured within a series of frequency encoding linear magnetic field gradients generates a spatial projection of the echo
Data Source
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AI summary
An echo-based single point imaging (ESPI) system (10) providing high-resolution oxygen images of a sample is disclosed. The ESPI system (10) employs spin echo detection of the resonance from a spin probe and concurrent Single Point Imaging (SPI) for spatial encoding of the oxygen concentration within the sample. Images are derived by comparing spin echo intensities of two images reconstructed at two time points selected at identical time intervals on either side of a refocusing pulse, eliminating artifacts associated with sample magnetic susceptibility and field inhomogeneity effects.