Multiple sequential image-fusion and direct MRI localisation of the subthalamic nucleus for deep brain stimulation

Aim. Deep brain stimulation (DBS) is the treatment of choice for advanced Parkinson's disease. The target coordinates are traditionally calculated in relation to the intercommissural distance. Anterior (AC) and posterior commissures (PC) may be visualised by the means of ventriculography, CT or MRI. Methods. We have studied the efficacy of direct visualisation of the subthalamic-red nucleus complex on MRI, the advantage of fusion of stereotactic CT and MR images (Multiple Sequences Image Fusion - MuSIF). These methods are combined with double check of indirect calculation of the target co-ordinates based on AC-PC line, as well as the corrispondence to the stereotactic electronic atlas. Results. Subthalamic nucleus (STN) was well recognisable in fused images in all 22 sides. At 3 months from surgery it was possible to reduce 76% of L-dopa equivalent daily dose. Dyskine-sias reduced to 50% and motor fluctuation up to 45%. Conclusion. In our experience MuSIF offers very high rate of accuracy in calculation of target co-ordinates. Direct visualisation of STN in MR and MuSIF are reliable and facilitate the accuracy of identification of target coordinates. Intraoperative neurophysiological recording increases the accuracy of microelectrode position.