Table 3.

Predictive modeling performance

Metric	Variables (#)	Conventional	Conventional Plus Advanced
R2	All variables	0.508 ± 0.093 (6)	0.660 ± 0.201 (23)
	RF rank	0.504 ± 0.065 (4)	0.749 ± 0.137 (4)
	RF (fixed variables)	0.496 ± 0.083 (T2, T1C, FLAIR, T1)	0.747 ± 0.168 (T2, FA, CBF, Ktrans)
RMSE (%)	All variables	5.34 ± 2.25	4.19 ± 1.78
	RF rank	5.47 ± 2.33	3.85 ± 1.82
	RF (fixed variables)	5.40 ± 2.34	3.46 ± 1.39
Max error across all folds (%)	All variables	30.50	27.03
	RF rank	28.94	24.93
	RF (fixed variables)	28.75	20.49

RF = random forest. Summary of the performance of the random forest model using variables selected by random forest rankings. Accuracy was estimated using 5-fold cross validation. Conventional = conventional MR only (T1, T2, T1 contrast enhanced, FLAIR, SWAN, T2*). Conventional plus advanced = conventional imaging plus diffusion, permeability and perfusion imaging. Numbers in parentheses indicate the number of variables included to obtain the predictive performance stated (see text).