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Short description of portfolio item number 1
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Published in Brain Structure and Function, 2019
We developed a semi-automatic algorithm to segmented myelinated axons in the electron microscopy data of a mouse brain sample and analyzed its micro-geometry, such as axonal diameter, caliber variation, axonal undulation, and fiber orientation dispersion. The segmentation and analysis code can be downloaded here.
Recommended citation: Lee, H. H., Yaros, K., Veraart, J., et al. (2019). "Along-axon diameter variation and axonal orientation dispersion revealed with 3D electron microscopy: implications for quantifying brain white matter microstructure with histology and diffusion MRI." Brain Structure and Function, 224:1469–1488. https://doi.org/10.1007/s00429-019-01844-6
Published in Emerging Infectious Diseases, 2020
We analyzed the National Health Insurance database in Taiwan, showing that rates of other infections were significantly lower after SARS-CoV-2 prevention measures were announced. This finding can be applied to cost-effectiveness of SARS-CoV-2 prevention.
Recommended citation: Lee, H. H., & Lin, S. H. (2020). "Effects of COVID-19 prevention measures on other common infections, Taiwan." Emerging infectious diseases, 26(10), 2509. https://doi.org/10.3201/eid2610.203193
Published in NeuroImage, 2020
In vivo diffusion MRI and Monte Carlo simulations indicate that the restriction along neurites is short-range disorder, and the diffusivity and kurtosis time-dependence scales as 1/√t. The 1-dimensional simulation code and power spectrum analysis can be downloaded here.
Recommended citation: Lee, H. H., Papaioannou, A., Novikov, D. S., & Fieremans, E. (2020). "In vivo observation and biophysical interpretation of time-dependent diffusion in human cortical gray matter." NeuroImage, 222, 117054. https://doi.org/10.1016/j.neuroimage.2020.117054
Published in NeuroImage, 2020
Monte Carlo simulation of diffusion inside realistic axonal shapes segmented from electron microscopy data of a mouse brain.
Recommended citation: Lee, H. H., Jespersen, S. N., Fieremans, E., & Novikov, D. S. (2020). "The impact of realistic axonal shape on axon diameter estimation using diffusion MRI." NeuroImage, 223, 117228. https://doi.org/10.1016/j.neuroimage.2020.117228
Published in Journal of Neuroscience Methods, 2021
Monte Calo simulation of diffusion in voxelized micro-geometry using CUDA C++. The code for narrow pulse PGSE could be downloaded here. The code for wide pulse PGSE will be released soon.
Recommended citation: Lee, H. H., Fieremans, E., & Novikov, D. S. (2021). "Realistic Microstructure Simulator (RMS): Monte Carlo simulations of diffusion in three-dimensional cell segmentations of microscopy images." Journal of Neuroscience Methods, 350, 109018. https://doi.org/10.1016/j.jneumeth.2020.109018
Published in Magnetic Resonance in Medicine, 2021
Removal of Gibbs-ringing artifacts caused by partial Fourier acquisition and zero filling interpolation in MRI data. The code can be downloaded here.
Recommended citation: Lee, H. H., Novikov, D. S. & Fieremans, E. (2021). "Removal of partial Fourier-induced Gibbs (RPG) ringing artifacts in MRI." Magnetic Resonance in Medicine, 86:2733-2750. https://doi.org/10.1002/mrm.28830
Published in NMR in Biomedicine, 2024
Monte Carlo simulations of diffusion in realistic axons segmented from electron microscopy data of a human brain sample. The simulation code can be downloaded here.
Recommended citation: Lee, H. H., Tian, Q., Sheft, M., et al. (2024). "The effects of axonal beading and undulation on axonal diameter estimation from diffusion MRI: Insights from simulations in human axons segmented from three-dimensional electron microscopy." NMR in Biomedicine, e5087. https://doi.org/10.1002/nbm.5087
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This is a 30-minute talk about how to set up Monte Carlo simualtions of diffusion from the script.
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This is a 60-minute talk about the microstructure imaging using diffusion MRI.
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This is a 60-minute talk about the basic of diffusion MRI.
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This is a 20-minute talk about the biophysics beyond the standard model of diffusion MRI.
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This is a 20-minute talk about Numerical Phantoms of diffusion MRI.
Undergraduate course, University 1, Department, 2014
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Workshop, University 1, Department, 2015
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