title: Intracranial Applications of MR Imaging-Guided Focused Ultrasound.
abstract: Initially used in the treatment of prostate cancer and uterine fibroids, the role of focused ultrasound has expanded as transcranial acoustic wave distortion and other limitations have been overcome. Its utility relies on focal energy deposition via acoustic wave propagation. The duty cycle and intensity of focused ultrasound influence the rate of energy deposition and result in unique physiologic and biomechanical effects. Thermal ablation via high-intensity continuous exposure generates coagulative necrosis of tissues. High-intensity, pulsed application reduces temporally averaged energy deposition, resulting in mechanical effects, including reversible, localized BBB disruption, which enhances neurotherapeutic agent delivery. While the precise mechanisms remain unclear, low-intensity, pulsed exposures can influence neuronal activity with preservation of cytoarchitecture. Its noninvasive nature, high-resolution, radiation-free features allow focused ultrasound to compare favorably with other modalities. We discuss the physical characteristics of focused ultrasound devices, the biophysical mechanisms at the tissue level, and current and emerging applications.
authors.affiliation: From the Department of Diagnostic Radiology and Nuclear Medicine (N.K., D.G., A.S., V.F., E.R.M.).
authors.forename: N
authors.identifier: 0000-0001-9385-0845
authors.initials: N
authors.lastname: Khanna
authors.affiliation: From the Department of Diagnostic Radiology and Nuclear Medicine (N.K., D.G., A.S., V.F., E.R.M.).
authors.forename: D
authors.identifier: 0000-0001-6741-5970
authors.initials: D
authors.lastname: Gandhi
authors.affiliation: From the Department of Diagnostic Radiology and Nuclear Medicine (N.K., D.G., A.S., V.F., E.R.M.).
authors.forename: A
authors.identifier: 0000-0001-5828-2969
authors.initials: A
authors.lastname: Steven
authors.affiliation: From the Department of Diagnostic Radiology and Nuclear Medicine (N.K., D.G., A.S., V.F., E.R.M.) vfrenkel@som.umaryland.edu.|Greenebaum Cancer Center (V.F.), University of Maryland School of Medicine, Baltimore, Maryland.
authors.forename: V
authors.identifier: 0000-0002-4230-0154
authors.initials: V
authors.lastname: Frenkel
authors.affiliation: From the Department of Diagnostic Radiology and Nuclear Medicine (N.K., D.G., A.S., V.F., E.R.M.).
authors.forename: E R
authors.identifier: 0000-0001-5869-9449
authors.initials: ER
authors.lastname: Melhem
mesh_terms: D001921:Brain / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D025321:Surgery, Computer-Assisted / Q000379:methods; D014464:Ultrasonic Therapy / Q000379:methods* / Q000639:trends