# Real Color Model of a Cadaver for Deep Brain Stimulation of the Subthalamic Nucleus
## 3 Results  
A real color volume model (file size: 98 MBytes), segmented volume model (file size: 33 MBytes), and virtual electrode (file size: 228 KBytes) were produced (voxel size: 0.5 mm \(\times\) 0.5 mm \(\times\) 0.5 mm). By using the real color volume model on the MRIcroGL, arbitrary planes could be produced freely. The location of the electrode could be assessed in the probe's eye planes and the horizontal, coronal, and sagittal planes. In the trajectory planes, the overall progress of electrode insertion could be assessed (Figure 2). The entry point (crown of the rostral middle frontal gyrus) and target point (dorsolateral part of the left subthalamic nucleus) obtained from 31 patients' MRIs were marked on the horizontal, coronal, and sagittal planes on the real color volume model through the registration. On average, the entry point was located at +50.5 mm in the horizontal plane, +26.0 mm in the coronal plane, and +32.0 mm in the sagittal plane on the anterior commissure-posterior commissure (AC-PC) coordinates. Around the entry point, the superior frontal sulcus, where surgical accidents are likely to occur, could be seen. The target point was located at \(-6.5\) mm in the horizontal plane, \(-4.5\) mm in the coronal plane,  
Figure 2: Various planes produced from the real volume model of sectioned images and a segmented volume model of a cadaver. The DBS electrode for the left subthalamic nucleus is displayed as an overlay. The entry point of the electrode is indicated with a yellow arrow head. and +10.0 mm in the sagittal plane on the AC-PC coordinates. Around the target point, care should be taken when passing the optic tract and posterior cerebral artery. The entry and target points corresponded well with the postoperative CTs of the 31 patients (Figure 3). Along the course of the electrode in the probe's eye plane on the real color volume model, three regions where surgical accidents are likely to occur were examined: the entry point, the lateral ventricle, and the target point (subthalamic nucleus). To avoid the artery inside the sulci in the entry point, the practitioner should choose the crown of the middle frontal gyrus. The superior and inferior frontal sulci should not be included in the course of the electrode (Figure 4) [19; 20]. Figure 3: Horizontal, coronal, and sagittal planes on a real color volume model with the marked entry point and target point of the DBS electrode. To prevent puncturing the lateral ventricle, the electrode was passed laterally to the caudate nucleus and medially to the internal capsule. Puncturing the lateral ventricle may cause leakage of the cerebrospinal fluid (Figure 4) [21,22]. The target point on the probe's eye plane was the dorsolateral part of the subthalamic nucleus. The neighboring structures of the target point were the hypothalamus, internal capsule, oculomotor nerve, limbic part of the subthalamic nucleus, red nucleus, medial lemniscus, and substantia nigra, which were identified (Figure 3). The structures near the target were affected by the electrical stimulation rather than mechanically by the electrode [3, 4, 5, 6]. In the coronal-like trajectory plane and sagittal-like trajectory plane on the real color volume model, the whole electrode and its neighboring structures could be seen at a glance. The electrode departed the crown of the middle frontal gyrus (entry point) and arrived  
Figure 4: Probe’s eye planes on a real color volume model from the entry point to the target point through the side of the lateral ventricle. The probe’s eye planes are displayed from the entry point (middle frontal gyrus) to the target point (dorsolateral part of the subthalamic nucleus). The curative effects when the electrode is placed at the subthalamic nucleus are written in blue. The adverse effects when the electrode is placed at different structures are written in red. at the dorsolateral part of the subthalamic nucleus (target point) through the lateral side of the lateral ventricle (waypoint).