John David Dickson1, Guy Barnett Williams2, Thomas Adrian Carpenter2, Richard E. Ansorge1
1Department of Physics, Cambridge University, Cambridge, Cambridgeshire, United Kingdom; 2Wolfson Brain Imaging Centre, Cambridge University, Cambridge, Cambridgeshire, United Kingdom
It has been suggested that extracellular fluid spins undergo bulk dephasing from those in intracellular fluid. This study provides direct evidence for this phenomenon and exploits it to make quantitative measurements of both the intra/extracellular fluid volume fractions and precession frequencies. This is achieved by fitting the data from a Gradient Echo Sampling of a Free Induction Decay (GESFID) sequence with a complex signal model.