Figure 7. Representitive images illustrating the generation of K^trans and v_e from a case in the ZdTha group at day 2 after treatment. A:

a source image from DCE-MRI showed two tumors (arrow) with reduced perfusion. B: a relative contrast agent concentration (C^rel) map derived from a serial of source images of DCE-MRI. Four regions of interest (ROIs) were contoured on the source images: the two tumors (R1 and R2), the normal liver (R3), and the abdominal aorta (R4, not shown). Then the four ROIs were transferred onto the C^rel map. R4 was used to determine the arterial input function. C: The curves for the four ROIs were measured and fit with the Tofts and Kermode model to calculate the K^trans and v_e. The optimal overlap of the black line (signal) on the red line (fit) indicated the best fitting of tumor signal curve with the model curve.