The Effect of Haematocrit Levels and Arrival Times on ASL Measures in Neonates.

Rishma Vidyasagar¹, Laurence Abernethy², Laura M. Parkes¹

Quantitative measures of ASL are dependent on many assumed values within the model such as T1 and arrival time. T1 has been shown to be strongly dependent on haematocrit levels, which is often assumed at a standard adult value. In neonates, haematocrit levels have been shown to vary significantly during the first few weeks, thus if not corrected can lead to incorrect quantification of CBF. Arrival time values are often measured at a single time point which could be incorrect in neonates. This study investigates these assumptions in a neonate population using a multiphase ASL sequence.