...
B1) white surface imperfections
aB1a. White surface too deep (segmentation of white matter does not capture all white matter and grey matter segmentation will include some white matter) – this may happen near the claustrum, in very lightly myelinated white matter, and in susceptibility areas
bB1b. White surface too superficial (segmentation of white matter extends into grey matter)
cB1c. Other [e.g. missed gyri or missed sulci]
B2) pial surface imperfections
aB2a. Pial surface too deep (segmentation of grey matter fails to capture all grey matter)
bB2b. Pial surface too superficial: blood vessel/venous sinus inclusion
cB2c. Pial surface too superficial: dural inclusion
dB2d. Other [e.g. pial surface extending into other structures like bone marrow]
...