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- Title
Oxygen saturation-dependent effects on blood transverse relaxation at low fields.
- Authors
Thomas, Dion G.; Galvosas, Petrik; Tzeng, Yu-Chieh; Harrison, Freya G.; Berry, Mary J.; Teal, Paul D.; Wright, Graham A.; Obruchkov, Sergei
- Abstract
Objective: Blood oxygenation can be measured using magnetic resonance using the paramagnetic effect of deoxy-haemoglobin, which decreases the T 2 relaxation time of blood. This T 2 contrast has been well characterised at the B 0 fields used in MRI (1.5 T and above). However, few studies have characterised this effect at lower magnetic fields. Here, the feasibility of blood oximetry at low field based on T 2 changes that are within a physiological relevant range is explored. This study could be used for specifying requirements for construction of a monitoring device based on low field permanent magnet systems. Methods: A continuous flow circuit was used to control parameters such as oxygen saturation and temperature in a sample of blood. It flowed through a variable field magnet, where CPMG experiments were performed to measure its T 2 . In addition, the oxygen saturation was monitored by an optical sensor for comparison with the T 2 changes. Results: These results show that at low B 0 fields, the change in blood T 2 due to oxygenation is small, but still detectable. The data measured at low fields are also in agreement with theoretical models for the oxy-deoxy T 2 effect. Conclusion: T 2 changes in blood due to oxygenation were observed at fields as low as 0.1 T. These results suggest that low field NMR relaxometry devices around 0.3 T could be designed to detect changes in blood oxygenation.
- Subjects
OXYGEN in the blood; OXYGEN saturation; MAGNETIC field effects; PARAMAGNETIC resonance; OXIMETRY; MAGNETIC resonance; PERMANENT magnets
- Publication
MAGMA: Magnetic Resonance Materials in Physics, Biology & Medicine, 2022, Vol 35, Issue 5, p805
- ISSN
0968-5243
- Publication type
Article
- DOI
10.1007/s10334-021-00993-2