Direct anatomical localization of the subthalamic nucleus on CT with comparison to Schaltenbrand-Wahren atlas

Stimulation of the subthalamic nucleus (STN) has become an accepted treatment for motor symptoms of Parkinson's disease. Generally, localization of the target is based on stereotactic atlas coordinates and magnetic resonance (MR) images. In this paper a method of direct anatomical localization of the STN on computed tomography (CT) images is described and compared with the Schaltenbrand-Wahren atlas. Serial CT scans were obtained at 1.5-mm interval and scan thickness of 3 mm, with the CT gantry and glabella-inion plane of the patient's head vertical. The STN was identified as a dense structure medial to the inner semicircular border of the internal capsule in the subthalamic region. Its visibility was increased by changing the window and level settings on the CT workstation computer. The center of the STN in relationship to the intercommissural line, determined by this technique, was similar to those found on standard atlases.