Intracranial applications of magnetic resonance-guided focused ultrasound.

The ability to focus acoustic energy through the intact skull on to targets millimeters in size represents an important milestone in the development of neurotherapeutics. Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel, noninvasive method, which--under real-time imaging and thermographic guidance--can be used to generate focal intracranial thermal ablative lesions and disrupt the blood-brain barrier. An established treatment for bone metastases, uterine fibroids, and breast lesions, MRgFUS has now been proposed as an alternative to open neurosurgical procedures for a wide variety of indications. Studies investigating intracranial MRgFUS range from small animal preclinical experiments to large, late-phase randomized trials that span the clinical spectrum from movement disorders, to vascular, oncologic, and psychiatric applications. We review the principles of MRgFUS and its use for brain-based disorders, and outline future directions for this promising technology.