The superior frontal gyrus consists of all cortex between the cingulate sulcus inferiorly, the superior frontal sulcus superiorly, and the precentral sulcus posteriorly. (Fig. 1, Fig. 2)
Masking of the superior frontal gyrus is done in the coronal view. Find a slice where the superior frontal sulcus is clearly visible and follow the sulcus to its most anterior slice. Draw a line from the superior frontal sulcus down to the olfactory sulcus and mask everything between this boundary and the interhemispheric fissure. (Fig. 3, Fig. 4)
Moving posteriorly, the cingulate sulcus will appear. At this time, the superior frontal gyrus is split into superior and inferior segments. Mask from the superior frontal sulcus to the superior segment of the cingulate sulcus. Follow the cingulate sulcus to the interhemispheric fissure and fill in everything within these boundaries. For the inferior segment, mask from the olfactory sulcus up to the inferior segment of the cingulated sulcus. Follow the cingulated sulcus to the interhemispheric fissure and mask everything within these boundaries. (Fig. 5)
Once the olfactory sulcus is no longer visible, only the superior segment of the superior frontal gyrus is masked.
End masking when the precentral sulcus first comes into view. This can be found by finding a slice in the axial view where the precentral sulcus is very clear, click on its most anterior point, then find the corresponding slice in the coronal view. (Fig. 6, Fig. 7)