Fig. 2.

Axial midbrain sections showing the subthalamic nucleus (STN) at maximal diameter of the red nucleus on 1.5-, 3-, and 7.0-T T2 MRI sequences. The horizontal white dotted line coincides with the Bejjani line; a white cross indicates the STN target point. A comparison showed high correspondence for x, y, and z STN coordinates between the 3 field strengths (Table 2). This is expected to result from high resemblance of the reference points used: the anterior red nucleus and medial STN border.