Comparison of atlas- and magnetic-resonance-imaging-based stereotactic targeting of the subthalamic nucleus in the surgical treatment of Parkinson's disease.

AIMS

To assess the variability of the subthalamic nucleus (STN) size, orientation and target coordinates from direct visualization on high-resolution magnetic resonance (MR) images in patients undergoing surgical intervention for Parkinson's disease.

METHODS

Sixty-six patients with Parkinson's disease were included in this study. The STN was visualized directly on high-resolution MR images, the size and orientation in both coronal and axial planes were recorded, as were the coordinates of the dorsolateral STN target in relation to the anterior-posterior commissural (AC-PC) line. The same STN target was defined in the Schaltenbrand atlas and atlas-based coordinates in proportion to the patient's AC-PC dimension were calculated. MR-imaging-based STN target coordinates were compared with the corresponding atlas-based coordinates.

RESULTS

Marked variation of STN size and orientation was observed. A significant difference was demonstrated on comparing left- and right-sided x and y coordinates. The comparison between MR-imaging-based and atlas-derived target coordinates demonstrated a significant difference in all directions except the left y coordinate.

CONCLUSIONS

This study demonstrates the substantial individual variability of STN size, orientation and target coordinates and a significant difference between target coordinates obtained by direct visual targeting on MR images and those obtained by indirect targeting based on atlases.