FIG 4. Coronal MR images through the red nucleus.

A, T2-weighted image from a control subject, a 58-year-old woman. The red nucleus is depicted as a round hypointense structure. Another hypointense area is lateral to the red nucleus (arrow).

B, Proton density-weighted image in the same section as in A. The SN (n) is depicted as an area of hyperintense gray matter inferolateral to the red nucleus (r).

C, T1-weighted image obtained in the same section as in A. The SN is not visible.

D, Coronal fast STIR image obtained in the same section as in A. The SN (n) is readily identified as an area of hyperintense gray matter. The red nucleus (r) is also depicted.

E, Video-reversed fast STIR image onto which the hypointense regions on a T2-weighted image are superimposed (shaded areas). The hypointense areas on the T2-weighted image are located on only the superolateral end of the SN.

F, Gross specimen of the human brain. The SN (n) is identified as a tilted bandlike area inferolateral to the red nucleus (r). The SN is present through the entire length of the midbrain, and its lower half is located beneath the red nucleus.