Parameters Derived from Triexponential Fit to Chosen Standard Input Function With and Without Prior Subtraction of Extravascular Background
| Background subtracted | a0 | a1 | a2 | b0 (min−1) | b1 (min−1) | b2 (min−1) |
|---|---|---|---|---|---|---|
| No [SP(t)] | 0.685 | 0.179 | 0.136 | 4.79 | 0.318 | 0.036 |
| Yes [SP′(t)] | 0.746 | 0.163 | 0.091 | 4.62 | 0.495 | 0.058 |
Standard input function before and after subtraction of extravascular background is denoted by SP(t) and SP′(t), respectively. SP(t) [or SP′(t)] = a0 exp[−b0t] + a1 exp[−b1t] + a2 exp[−b2t], where input functions have been adjusted to initial maximum of unity at time t = 0.