In patients with deep brain stimulation (DBS), poor postoperative outcome or 
unexpected clinical change require brain imaging to check the lead location. 
Here, we studied safety, reliability and prognostic value of transcranial 
sonography (TCS) for DBS lead localization applying predefined TCS criteria. 
After measuring thermal effects of TCS and imaging artefact sizes of DBS lead 
using a skull phantom, we prospectively enrolled 34 patients with DBS of globus 
pallidus internus, ventro-intermediate thalamic or subthalamic nucleus. TCS had 
no influence on lead temperature, electrical parameters of DBS device or 
clinical state of patients. TCS measures of lead coordinates agreed with MRI 
measures in anterior-posterior and medial-lateral axis. Lead dislocation 
requiring reinsertion was reliably detected. Only patients with optimal lead 
position on TCS had favorable clinical 12-month outcome (>50% improvement), 
whereas unfavorable outcome (<25% improvement) was associated with suboptimal 
lead position. TCS may therefore become a first-choice modality to monitor lead 
location.