Fig. 6

Linear regression comparing CMRGlu estimates from IDIF (y-axis) and MDIF (x-axis) for total GM (exes) and WM (circles) TACs extracted from healthy individuals (n = 18). Line-of-best fit is shown as a solid line. The identity line is represented by the dashed line. Average (± standard error) regression for GM had a slope of 0.85 ± 0.06 [0.71 to 0.98] and an intercept of 3.1 ± 1.6 µmol/100 g/min [− 0.2 to 6.5 µmol/100 g/min] (R² = 0.92, \(\rho\) = 0.96, p < 0.001). Similarly, average (± standard error) regression for WM had a slope of 0.82 ± 0.06 [0.69 to 0.95] and an intercept of 1.7 ± 0.7 µmol/100 g/min [0.2 to 3.1 µmol/100 g/min] (R² = 0.92, \(\rho\) = 0.96, p < 0.001). CMRGlu: Cerebral metabolic rate of glucose; GM: Grey matter; IDIF: Image-derived input function; MDIF: Model-derived input function; TAC: Time-activity curve; WM: White matter