Kishor Karki1, Ramesh Paudyal1, Tavarekere N. Nagaraja2, James R. Ewing1,3, Joseph D. Fenstermacher2, Robert A. Knight1,3
1Department of Neurology, Henry Ford Hospital, Detroit, MI, United States; 2Department of Anesthesiology, Henry Ford Hospital, Detroit, MI; 3Department of Physics, Oakland University, Rochester, MI, United States
The present study investigates the possibility of using an average arterial input function (AIF) obtained from direct blood sampling experiments to estimate bloodbrain barrier (BBB) permeability or blood-to-brain transfer constant (Ktrans) of Gd-DTPA for a step-down infusion (SDI) procedure instead of using the individual MRI derived AIF. Enhanced spatial resolution of areas with BBB opening was generally observed with the SDI technique. The Ktrans values from both types of AIFs agreed closely and were highly correlated, suggesting that an averaged AIF for a given contrast agent obtained from a standard technique can be used to assess vascular permeability.