Deuterium MRI for Non-Invasive Metabolic Flux Imaging
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Solution Overview
Problem
Current methods for diagnosing cancer and non-alcoholic steatohepatitis (NASH) are limited by the use of radioactive tracers, invasive procedures, and inability to accurately measure metabolic flux, leading to inefficiencies and risks in patient care.
Innovation Solution
Deuterium magnetic resonance imaging (DMI) is used to detect hydrogen-deuterium oxide (HDO) production from deuterium-labeled substrates, providing a non-invasive and sensitive method to assess glucose metabolism and fatty acid oxidation in tissues, allowing for early detection of cancer and NASH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radioactive tracers like 18FDG are used for PET imaging, then sensitivity for detecting glucose uptake is improved, but patients are exposed to ionizing radiation which carries unknown but real risk of secondary cancer
Solution Approach 1:
The patent uses deuterium-labeled glucose as a non-radioactive tracer that can be administered repeatedly without cumulative radiation risk. The deuterium label provides sufficient signal through MRI detection while avoiding the harmful long-term effects of radioactive isotopes, enabling safe repeated imaging for monitoring disease progression and treatment response.
Solution Approach 2:
The patent changes the detection parameter from radioactive signal (PET) to magnetic resonance signal (MRI) by using deuterium-labeled substrates. This parameter change allows detection of metabolic flux through the quadrupolar relaxation properties of deuterium, providing an alternative that maintains sensitivity while eliminating radiation exposure.
2Measurement precision
If 18FDG PET is used for high-resolution mapping of glucose uptake, then diagnostic capability is improved, but repetitive scanning for evaluating disease progression is limited due to radiation exposure
Solution Approach 1:
The deuterium-labeled glucose tracer enables repeated administration and imaging without cumulative radiation dose concerns. Patients can undergo multiple scans over time to evaluate disease progression and treatment response, transforming a one-time diagnostic tool into a longitudinal monitoring solution.
3Measurement precision
If CEST MRI is used to detect glucose uptake indirectly, then sensitivity relative to direct detection is improved, but the technique is hampered by water exchange rates at physiological pH
Solution Approach 1:
The patent uses deuterium-labeled substrates as an intermediary that undergoes metabolic conversion to labeled metabolites (lactate, HDO) which can then be detected by MRI. This intermediary approach bypasses the water exchange rate limitations of CEST by detecting the metabolic products directly through their characteristic NMR signals.
Solution Approach 2:
The patent replaces the chemical exchange mechanism of CEST with direct metabolic conversion and detection. Instead of relying on proton exchange between glucose and water, the method uses enzymatic metabolism to convert deuterium-labeled glucose to labeled metabolites, which are then detected through their intrinsic NMR properties without requiring chemical exchange.
4Measurement precision
If dissolution dynamic nuclear polarization (dDNP) is used to enhance 13C MR signal, then signal-to-noise ratio is improved >10,000 times, but the technique is limited to molecules with long relaxation times
Solution Approach 1:
The patent changes the nuclear spin parameter from 13C (spin 1/2) to deuterium (spin 1), which has different relaxation properties. The quadrupolar nature of deuterium provides favorable relaxation times that enable both high signal enhancement and applicability to metabolites like glucose that have short relaxation times, overcoming the limitation of dDNP.
5Measurement precision
If liver biopsy is used as the gold standard for diagnosing NASH, then diagnostic accuracy is improved, but the procedure carries risks including bleeding and sampling error
Solution Approach 1:
The patent replaces the mechanical invasive procedure of liver biopsy with non-invasive magnetic resonance imaging. By using deuterium-labeled substrates and detecting metabolic flux through MRI, the method provides diagnostic information about liver metabolism without physical tissue removal, eliminating bleeding risks while maintaining diagnostic capability.
Solution Approach 2:
The patent uses deuterium-labeled metabolic substrates as intermediaries to probe liver metabolism non-invasively. These tracers undergo metabolism in the liver, and the resulting labeled metabolites serve as reporters of hepatic metabolic function, providing diagnostic information without requiring direct tissue sampling.
6Measurement precision
If 13C labeled glucose with spin editing is used for isotopomer analysis, then metabolic flux measurement is improved, but the 13C enrichment is not easily determined due to overlap with fatty acid resonances
Solution Approach 1:
The patent changes the isotopic label from 13C to deuterium, which has a different Larmor frequency and chemical shift properties. This parameter change separates the signal from fatty acid resonances that overlap in the 13C spectrum, allowing clear detection and quantification of deuterium-enriched metabolites without spectral interference.
Data Source
AI summary
Disclosed herein are methods for imaging a tissue in a subject that involves administering to the subject a composition comprising deuterium-labeled glycolytic or fatty acid substrate and imaging the subject with deuterium magnetic resonance imaging (DMI) to detect hydrogen-deuterium oxide (HDO) in tissues of the subject. The disclosed methods can be used to detect changes in metabolic activity in a tissue. The disclosed methods can also be used to detect cancers.