I wonder that whether I can use the command aparc2statstable to get the cortical thickness or is it better to get the cortical thickness of a volume defined ROI or is there the easy way to get the most accurate cortical thickness from ROI  

I am following the pipeline "VolumeRoiCorticalThickness" but I do not understand how I can get ROI mask called ROI5.nii and TT_avg152T1.nii.

Sorry if this question is too obvious for me to overlook something.

Any help is appreciated since I am newbie on FreeSurfer.

Best regards,