Els Fieremans1, Dmitry S. Novikov1, Eric E. Sigmund1, Kecheng Liu2, Jens H. Jensen1, Joseph A. Helpern1,3
1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, United States; 2Siemens Medical Systems, United States; 3Center for Advanced Brain Imaging, Nathan S. Kline Institute, Orangeburg, NY, United States
The diffusivity measured in tissue in vivo depends on the diffusion time and is sensitive to tissue microstructure. Here we measure the time-dependent diffusion in the human calf muscle of healthy subjects. Based on our recent modeling of diffusion restricted by permeable membranes, we derive estimates of the free diffusion coefficient, membrane permeability, surface-to-volume ratio and mean fiber diameter. The obtained fiber diameter values agree very well with histological findings. Hence, we demonstrate here for the first time a non-invasive method to create parametric maps of cell membrane permeability and cell size.