Update in the clinical application of focused ultrasound.

To review the most recent evidence about the clinical applicability of transcranial MRI-guided focused ultrasound (MRgFUS), including clinical evidence and indications, recent technical developments for its use and future prospects. Unilateral MRgFUS thalamotomy for both essential and parkinsonian tremors is an approved and well established therapy. Recent studies have focused on its long-term safety and efficacy as well as technical advances for refining the approach. Moreover, ultrasound has expanded its application in Parkinson's disease, with clinical trials successfully targeting other brain regions like the subthalamic nucleus, the globus pallidus and the pallidothalamic tract, providing benefits for features that thalamotomy neglects. New indications, such as focal dystonia or neuropsychiatric conditions (namely obsessive-compulsive disorder and depression) have also been explored, with encouraging preliminary results. Finally, the application of ultrasound in low-intensity modality allows other approaches like focal blood-brain barrier opening and neuromodulation, which promise to be highly relevant in translational research. MRgFUS is a growing emergent technique. Its application in clinical routine is becoming widely accepted as a therapeutic option. Novel approaches and new potential applications are anticipated.