Els Fieremans1, Jens H. Jensen1, Ali Tabesh1, Joseph A Helpern1,2
1Center of Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States; 2Center for Advanced Brain Imaging, Nathan S. Kline Institute, Orangeburg, NY, United States
Diffusional kurtosis imaging (DKI) has been proposed as a clinically feasible extension of DTI to probe restricted water diffusion in biological tissues. We exploit here the DKI information to estimate the axonal water fraction (AWF), a measure of axonal density. We validate its measurement against the fraction as obtained from bi-exponential fitting in healthy controls, showing a very good agreement. Whereas other advanced diffusion models typically require high b-values, we propose a DKI WM model based on b-values up to 2000 s/mm2. Assessing the axonal density using DKI is clinically feasible and could potentially provide important information on neurodegenerative disorders.