Naoki Ohno1, Tosiaki Miyati1, Satoshi Kobayashi2, Toshifumi Gabata2. 1. Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan. 2. Department of Radiology, Kanazawa University Hospital, Kanazawa, Japan.
Abstract
BACKGROUND: To noninvasively obtain more detailed information on brain perfusion and diffusion using modified triexponential analysis. METHODS: On a 3.0 Tesla MRI, diffusion-weighted imaging of the brain with multiple b-values was performed in healthy volunteers (n = 12). We derived perfusion-related, fast-free, and slow-restricted diffusion coefficients (Dp , Df , and Ds , respectively) and fractions (Fp , Ff , and Fs , respectively) in the frontal and occipital white matter, caudate nucleus, and putamen calculated from triexponential function by a two-step approach. Ds was initially determined using monoexponential function in b-values over 1000 s/mm(2) and was applied to triexponential function. Additionally, the literature value of the diffusion coefficient of free water at 37 °C was assigned to Df . Finally, Dp and fractions were derived using all b-values. Moreover, biexponential analysis was performed and compared with triexponential analysis. We also determined regional cerebral blood flow (rCBF) using arterial spin labeling and assessed its relation with each diffusion parameter. RESULTS: Significant positive correlations between Dp and rCBF were found in the caudate nucleus (R = 0.84; P = 0.01) and putamen (R = 0.86; P = 0.01), whereas no diffusion parameters were significantly correlated with rCBF on biexponential analysis (P > 0.05 for all). CONCLUSION: Diffusion analysis with triexponential function enables noninvasive gathering of more detailed information on brain perfusion and diffusion.
BACKGROUND: To noninvasively obtain more detailed information on brain perfusion and diffusion using modified triexponential analysis. METHODS: On a 3.0 Tesla MRI, diffusion-weighted imaging of the brain with multiple b-values was performed in healthy volunteers (n = 12). We derived perfusion-related, fast-free, and slow-restricted diffusion coefficients (Dp , Df , and Ds , respectively) and fractions (Fp , Ff , and Fs , respectively) in the frontal and occipital white matter, caudate nucleus, and putamen calculated from triexponential function by a two-step approach. Ds was initially determined using monoexponential function in b-values over 1000 s/mm(2) and was applied to triexponential function. Additionally, the literature value of the diffusion coefficient of free water at 37 °C was assigned to Df . Finally, Dp and fractions were derived using all b-values. Moreover, biexponential analysis was performed and compared with triexponential analysis. We also determined regional cerebral blood flow (rCBF) using arterial spin labeling and assessed its relation with each diffusion parameter. RESULTS: Significant positive correlations between Dp and rCBF were found in the caudate nucleus (R = 0.84; P = 0.01) and putamen (R = 0.86; P = 0.01), whereas no diffusion parameters were significantly correlated with rCBF on biexponential analysis (P > 0.05 for all). CONCLUSION: Diffusion analysis with triexponential function enables noninvasive gathering of more detailed information on brain perfusion and diffusion.
Authors: Anna S Rydhög; Filip Szczepankiewicz; Ronnie Wirestam; André Ahlgren; Carl-Fredrik Westin; Linda Knutsson; Ofer Pasternak Journal: Neuroimage Date: 2017-04-13 Impact factor: 6.556