Figure 2. Plasma contrast agent concentration–time course (C_p(t)) curves measured from superior sagittal sinus (SSS) in a patient with an anaplastic astrocytoma (case 3) and derived leakage profiles (LPs) on day 0 and day 2. (a) C_p(t) curves sampled with a time interval of 5.05 s between each dynamic phases on day 0 () and day 2 (). C_p(t) data are fitted with variate functions. Bolus arrival time in the SSS on day 0 is 4.45 s earlier than on day 2. In addition, the C_p(t) curve acquired on day 0 is slightly narrower than on day 2 (full width at half height on day 1: full width at half height on day 2=10.14 s:12.11 s) with a higher peak value. The variate functions are concatenated with a straight horizontal line. The height of this line represents the level of a steady state of contrast agent concentration in plasma after recirculation. (b) LPs on day 0 (solid line) and day 2 (dashed line) are calculatd from the two concatenated variate functions. The difference between areas under these two curves is small (C_p(t)_{day 0}:C_p(t)_{day 2}=150.29:147.73).