Table 3.

Regression performances through five-fold cross-validation.

Fold	Automatic ROI method			Manual ROI method
	RMSE (years)	MAE (years)	R2	RMSE (years)	MAE (years)	R2
1	0.363	0.282	0.985	0.579	0.540	0.956
2	0.389	0.308	0.985	0.741	0.687	0.924
3	0.367	0.280	0.986	0.629	0.578	0.948
4	0.420	0.324	0.982	0.563	0.522	0.952
5	0.413	0.307	0.977	0.742	0.651	0.919
Average	0.390	0.300	0.983	0.651	0.595	0.934

ROI: region of interest, RMSE: root mean squared error, MAE: mean absolute error.