Hyperpolarized Xenon MRI for Brain Activation Mapping
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Solution Overview
Problem
Current functional MRI (fMRI) techniques face challenges in accurately detecting brain activation due to small signal differences, requiring sophisticated statistical analysis and lacking in spatial resolution, especially in detecting changes in cerebral blood flow which are indicative of neural activity or pathology.
Innovation Solution
The method involves administering hyperpolarized xenon gas to an individual, taking control and stimulus chemical shift images, and subtracting these to identify activated brain regions by measuring changes in xenon chemical shift and spin-spin relaxation times, which correlate with blood flow changes, allowing for precise mapping of brain activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional BOLD fMRI is used to detect brain activation, then the technique can identify activated regions, but the signal differences are very small requiring sophisticated statistical analysis
Solution Approach 1:
The patent changes the physical parameter being measured from BOLD signal (magnetic susceptibility changes) to hyperpolarized xenon chemical shift and relaxation times. This parameter change provides inherently larger signal differences that are more easily detected and analyzed, reducing the need for sophisticated statistical methods while maintaining activation detection capability
Solution Approach 2:
The patent introduces hyperpolarized xenon gas as an intermediary substance that dissolves in blood and provides a measurable signal. This intermediary mediates between the physiological process (blood flow changes) and the detection system, providing a stronger, more directly measurable signal than conventional BOLD fMRI
2Measurement precision
If conventional fMRI techniques are used, then brain activation can be detected, but spatial resolution is insufficient for detecting cerebral blood flow changes
Solution Approach 1:
The patent measures chemical shift and spin-spin relaxation times of hyperpolarized xenon instead of relying on conventional fMRI parameters. These parameter changes provide enhanced spatial resolution and more reliable blood flow detection, as the xenon signal directly reflects cerebral blood flow dynamics with greater spatial precision
3Measurement precision
If hyperpolarized xenon gas is administered and chemical shift imaging is performed, then sensitivity and spatial resolution are improved, but the procedure complexity increases
Solution Approach 1:
The patent performs preliminary hyperpolarization of the xenon gas before administration to the subject. This preliminary action creates a highly polarized state that provides strong NMR signals, enabling improved sensitivity and spatial resolution. The complexity is managed by performing this step beforehand rather than during the actual imaging procedure
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 provides higher sensitivity and spatial resolution in detecting brain activation and blood flow changes, enabling early diagnosis of neurodegenerative diseases and monitoring of tissue health by directly measuring hemodynamic responses, outperforming existing fMRI and EEG techniques.
Implementation Method 1
measuring a chemical shift of xenon dissolved in blood of the individual
Implementation Method 2
administering a first quantity of hyperpolarized xenon gas to an individual
Implementation Method 3
measuring a chemical shift of dissolved xenon in the blood of the individual; calculating an effective spin-spin relaxation time constant
Implementation Method 4
taking a control chemical shift image (either 2D or 3D) of the brain of the individual
Data Source
AI summary
Described herein is a method for detecting changes in blood flow in a tissue portion and/or body portion of an individual. The method can be used to detect any sort of pathology, trauma or insult which results in blood flow change. Specifically, this method uses hyperpolarized 129Xe MRI to detect xenon perfusion changes in tissues such as brain tissue that corresponds to changes in blood flow, for example, changes caused by functional activities of the brain or regions of the body where blood flow may be compromised.