Table 2 Correlation analysis for K_i and its surrogate parameters from different quantification methods; the squared correlation coefficient (R²), p value(p), and linear regression equations with each quantification method were listed in the table and the results of strongest correlation was marked in bold

DTW K_i (10 + 5 min)

R² = 0.971

R² = 0.990

R² = 0.990

p < 0.01

p < 0.01

p < 0.01

y = 1.04*x − 0.0013

y = 0.099*x + 0.0001

y =  x − 0.0002

Patlak K_i (30–60 min)

R² = 0.961

R² = 0.863

R² = 0.990

p < 0.01

p < 0.01

p < 0.01

y = 0.99*x + 0.002

y = 0.94*x + 0.0002

y = 0.99*x + 0.0008

FUR (50–60 min)

R² = 0.967

R² = 0.937

R² = 0.972

p < 0.01

p < 0.01

p < 0.01

y = 1.13*x + 0.0033

y = 1.2*x + 0.0013

y = 1.08*x + 0.0028

SUV (50–60 min)

R² = 0.447

R² = 0.729

R² = 0.390

p < 0.01

p < 0.01

p = 0.054

y = 126.66*x + 1.722

y = 159.22*x + 0.2178

y = 121.1*x + 1.113