Intra- and post-operative monitoring of deep brain implants using transcranial ultrasound

Transcranial sonography (TCS) of the brain parenchyma meanwhile allows a high-resolution imaging of deep brain structures in the majority of adults. A new application of TCS is the intra- and post-operative visualization with TCS and the TCS-assisted insertion of deep brain stimulation (DBS) electrodes. In pilot studies it has been shown that the TCS-assisted insertion of DBS electrodes into the subthalamic nucleus and the globus pallidus interna is feasible and safe provided the exact knowledge on the extent of electrode TCS imaging artifacts. Even more, TCS can be recommended for the post-operative monitoring of DBS electrode position. Dislocation of a DBS electrode can be easily detected. In a recent longitudinal study we could demonstrate that TCS measures of lead coordinates agreed with MRI measures in anterior–posterior and medial–lateral axis, and that the TCS-based grading of optimal vs suboptimal lead location predicts the clinical 12 months outcome of patients with movement disorders. Currently, an international multi-center study is being planned to further prove the value of TCS in the post-operative monitoring of DBS electrode position. This trial is intended to start in 2012, and is still open for joining. The obvious advantages of TCS will promote its increasing use for the intra- and post-operative monitoring of deep brain implants.