Investigation of the Necessity of Pre-Contrast T1-Determination in DCE MRI; Simulations and Clinical Data

Christopher Larsson¹, Magne Kleppest¹, Atle Bjrnerud¹, ²

Dynamic contrast-enhanced MRI is an established method to assess blood-brain barrier integrity and brain hemodynamics. Standard tracer kinetic models are established for estimation of kinetic parameters. Quantification requires an accurate estimation of the CA induced change in T1 relaxation rate in tissue and blood which in turn require knowledge of baseline T1 values (T1,0) . The need for T1,0-data results in additional scan-time, and raises challenges related to image co-registration and additional image processing steps. The added value of using T1,0 maps in DCE analysis has thus been questioned. The purpose of this study was to compare Ktrans values in primary brain tumors obtained using fixed T1,0-values compared to using calculated pixel-wise T1-values through simulations and clinical data. A secondary aim was to assess the variation in baseline T1-values observed in brain tumors.