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Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
Published on: November 12, 2016
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PRO-QUEST: a rapid assessment method based on progressive saturation for quantifying exchange rates using saturation
Eleni Demetriou1, Mohamed Tachrount1, Moritz Zaiss2
1Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom.
Magnetic Resonance in Medicine
|March 6, 2018
Summary
A new MRI technique, PRO-QUEST, significantly reduces scan time for measuring chemical exchange rates. This advanced method offers improved specificity for mapping pH changes in vivo, aiding stroke research.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Biophysical Chemistry
Background:
- Chemical Exchange Saturation Transfer (CEST) MRI is a valuable tool for in vivo pH mapping.
- Standard CEST MRI techniques can be time-consuming and susceptible to artifacts.
Purpose of the Study:
- To develop a novel MRI pulse sequence for rapid measurement of chemical exchange rates.
- To improve the efficiency and specificity of CEST MRI for pH mapping.
Main Methods:
- Development of the PRO-QUEST (progressive saturation for quantifying exchange rates using saturation times) pulse sequence.
- Utilizing non-steady-state water magnetization sampling with interleaved off-resonance saturation and Look-Locker acquisition.
- Derivation of a theoretical framework and equations for calculating exchange rates.
Main Results:
- PRO-QUEST reduced scan time from 58 to 16 minutes compared to standard QUEST.
- Accurate exchange rate measurements were validated with amino acid phantoms and in vivo rat stroke models.
- Demonstrated increased specificity for ischemic acidification in stroke imaging compared to standard amide proton transfer-weighted imaging.
Conclusions:
- PRO-QUEST offers a significantly faster and more robust method for in vivo pH mapping.
- The technique is insensitive to nonchemical exchange factors like direct water saturation.
- PRO-QUEST is a promising alternative for researchers and clinicians studying pH dynamics in various conditions.
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