Berron et al. (2017) for ErC, PhC, PrC and Hc subfields on 7T TSE-T2w images
Maass et al. (2015) on 7T T1w MPRAGE offers some sort of protocol to segment the antero-medial and postero-lateral regions of the ErC
Wisse et al. (2012) for ErC and Hc subfields on 7T TSE-T2w images
Tutorial slides of an annotated expansion of the Maass protocol, which also includes a blurb on running the Automatic Segmentation of Hippocampal Subfields, ASHS, tools from the Penn Image Computing and Science Laboratory (PICSL) at the Department of Radiology at the University of Pennsylvania):
On coronal slices, corresponds to the appearance of the amygdala, which in turn corresponds to the start of the limen insula (white matter fibers connecting the frontal and temporal lobes).
On coronal slices, ErC ends when the collateral sulcus disappears.
Some protocols mark ErC up the medial banks of the collateral sulcus depending on sulcus depth (.e.g Insausti et al. 1998), but not Maas et al. (2015) who argues for the variability of such a procedure
anteriorly: amygdala
when gyrus ambiens disappears and Hc fissure opens: parasubiculum
This is very vague