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Bi-exponential 23 Na T2 * component analysis in the human brain.
Frank Riemer1,2, Bhavana S Solanky1, Claudia A M Wheeler-Kingshott1
1Queen Square MS Centre, NMR Research Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, UK.
NMR in Biomedicine
|February 27, 2018
Summary
This study measured sodium (23Na) transverse relaxation time T2* in the healthy human brain using ultra-short echo times. Results provide the first detailed T2* values for various brain regions, aiding future neuroimaging research.
Area of Science:
- Magnetic Resonance Imaging
- Neuroimaging
- Biophysics
Background:
- Sodium (23Na) magnetic resonance imaging (MRI) offers insights into brain physiology.
- Quantifying sodium T2* relaxation times is crucial for understanding tissue microstructure.
- Previous studies have limitations in accurately measuring short T2* components in the brain.
Purpose of the Study:
- To measure sodium transverse relaxation time T2* in the healthy human brain.
- To present the first comprehensive dataset of 23Na T2* values across various anatomical locations using ultra-short echo times.
- To compare results obtained from bi-exponential and continuous distribution fitting models.
Main Methods:
- Five healthy subjects underwent MRI scans with 18 echo times, including ultra-short echo times down to 0.17 ms.
- Sodium T2* values were calculated voxel-by-voxel using both bi-exponential and continuous distribution models.
- Region of interest-based inverse Laplace transform was employed for continuous distribution analysis.
Main Results:
- Bi-exponential fitting yielded average T2* values of 3.4 ms (short) and 23.5 ms (long) in white matter (WM), and 3.9 ms (short) and 26.3 ms (long) in grey matter (GM).
- Continuous distribution fits provided average T2* values of 3.1 ms (short) and 18.8 ms (long) in WM, and 2.9 ms (short) and 17.2 ms (long) in GM.
- This study presents the first reported 23Na T2* values for short and long components in diverse brain regions using ultra-short echo times.
Conclusions:
- The study successfully measured and characterized sodium T2* in the healthy human brain using advanced MRI techniques.
- The findings provide essential reference data for sodium T2* values in different brain tissues.
- These results pave the way for improved sodium MRI applications in neurological research and diagnostics.
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