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. Author manuscript; available in PMC: 2009 Sep 8.

Published in final edited form as: Eur J Nucl Med Mol Imaging. 2008 May 6;35(10):1899–1911. doi: 10.1007/s00259-008-0796-z

Fig 2 — Schematic diagram of the procedure to analyze error sensitivity in hepatic arterial (f_a) and portal flow (f_p) values against assumed k_g (A) and time delay (B). Portal input curves were created by changing the value of k_g from 0.35 to 0.65/min in (A) and by shifting the time from 0 to 10 sec in (B), respectively, and combinations of the arterial (C_A) and simulated portal (C_P) curves were used as the simulated dual input functions (DIF). Sets of tissue time acticity curves (TAC) were generated from these simulated DIFs, by assuming ten values of f_a from 13 to 17 ml/min/100g. In turn, each set of tissue TACs was used to back-estimate DIF fixing k_g as 0.5/min and time delay as 0.0 sec. Finally, f_a and f_p were calculated from estimated DIFs for each k_g and delay time. TAC: time activity curve, DIF: dual input function.

Fig 2 — Schematic diagram of the procedure to analyze error sensitivity in hepatic arterial (f_a) and portal flow (f_p) values against assumed k_g (A) and time delay (B). Portal input curves were created by changing the value of k_g from 0.35 to 0.65/min in (A) and by shifting the time from 0 to 10 sec in (B), respectively, and combinations of the arterial (C_A) and simulated portal (C_P) curves were used as the simulated dual input functions (DIF). Sets of tissue time acticity curves (TAC) were generated from these simulated DIFs, by assuming ten values of f_a from 13 to 17 ml/min/100g. In turn, each set of tissue TACs was used to back-estimate DIF fixing k_g as 0.5/min and time delay as 0.0 sec. Finally, f_a and f_p were calculated from estimated DIFs for each k_g and delay time. TAC: time activity curve, DIF: dual input function.