pituitary-green; posterior pituitary (non contrast only)-orange; infundibulum-aqua
On noncontrast MR, the posterior pituitary has a higher signal than the anterior part of the gland, and so appears lighter in color. This difference is not evident after administration of Gadolinium.

carotids-red

optic nerves, chiasm and proximal tracts-yellow

Image series A is with gadolinium and series B is without gadolinium. Look for high signal in series A in the deep vascular areas of the brain, like the choroid plexus along the lateral ventricles, to determine that contrast was given.