Combined Arterial Spin Labelling & Diffusion Weighted Imaging for Estimation of Capillary Volume Fraction & Permeability-Surface Product in the Human Brain

Patrick William Hales¹, Chris A. Clark¹

We present a methodology to measure flow, capillary permeability-surface product (PS) and capillary volume fraction (vbw) in the human brain, using combined diffusion weighted imaging (DWI) and arterial spin labelling (ASL). Local values of vbw were calculated from DWI data using the intra voxel incoherent motion theory. These data were used in a two-compartment model of time-series ASL data in the same subject. Mean values in three healthy subjects were flow = 42.6 2.7 ml/100g/min, PS = 58.68.1 ml/100g/min. A slight under-estimation of PS is caused by partial volume contamination from CSF, which we aim to eliminate in future studies.