Meeting Banner
Abstract #2040

Measuring Bi-Exponential Transverse Relaxation of the ASL Signal at 9.4T to Estimate Arterial Oxygen Saturation and the Time of Exchange of Labelled Blood Water Into Cortical Brain Tissue

Jack A. Wells1, Bernard Siow1, Mark F. Lythgoe1, David L. Thomas2

1UCL Centre for Advanced Biomedical Imaging, UCL Division of Medicine and Institute of Child Health, London, United Kingdom; 2Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London. ML and DT are joint senior authors.

The transverse decay of the FAIR ASL signal at 5 inflow times (TIs) was measured in the rat brain at 9.4T. Bi-exponential behavior was observed that appears to derive from different T2 values associated with the intra-vasculature (IV) and extra-vascular (EV) compartments. A two compartment bi-exponential model was used to assess the relative contribution of the IV and EV compartments to the ASL signal at the 5 TIs, without needing to assume a constant T2 for labeled blood water in the vessels. This novel method was applied to estimate tissue transit time and the oxygen saturation on the arterial side of the vasculature

Abstract PDF

Keywords

accuracy accurate acquisition adapted addition agent animals applied approximation array arterial assessment authors axis barrier biomedical blood bolus brain close closely coil component components constraints control corresponds cortex cortical curve decay define described determination diameter differentiate direct disease disrupting division equal estimation evidence exchange exchanged exchanges exponential extra fair fast fits fitted fitting five fixed flow future good gradual greater hard head health healthy horizontal important improve incorporating increasing inflow inner institute invasive inversion investigation joint kingdom known labeled length mark marked matching matrix measuring medical micro model models mono neurology novel often oxygen oxygenation part particularly pathology precisely priors processes providing pulsed pulses quantification quantitative rapid rats readout rehabilitation repair repeated reported represents returning sample sampling saturation scale selective senior separate separately sets setting short shot side significantly slice slow space spin square studies taken takes therapies tissue transit transmission transverse typical unconstrained understanding units validation vascular vessels water width