MRgFUS

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive therapeutic modality that combines high-intensity focused ultrasound with magnetic resonance imaging to target tissue precisely while monitoring temperature in real time. The system uses an external transducer array to focus energy at a defined point inside the body, and MRI provides high-resolution planning images and real-time thermometry to guide and verify treatment.

Mechanistically, MRgFUS concentrates ultrasound energy at a focal point, causing rapid heating and tissue modification. Real-time MRI thermometry tracks temperature changes during sonication, enabling controlled lesioning or modulation of tissue while sparing surrounding structures. This combination allows surgeons to perform targeted ablations without incisions and with immediate imaging feedback.

Common clinical uses include neurosurgical applications such as thalamic ablation for essential tremor and other tremor disorders, as well as noninvasive treatments for uterine fibroids. MRgFUS is also investigated for pain palliation in cancer and other conditions, and broader neurological indications continue to be explored in clinical trials. Many uses are still under investigation or limited to specialized centers.

Treatment is typically performed in an MRI suite, with the patient under mild sedation or anesthesia depending on the target and protocol. Delivery of ultrasound energy can be impeded by skull properties and other tissue characteristics, and precise targeting requires strict immobilization and system calibration. Potential adverse effects include transient sensory changes, headaches, or neurological deficits, with most events being dose-related or reversible. The technique is not suitable for all targets or lesion sizes, and access, cost, and infrastructure requirements can limit availability.

Regulatory approvals for MRgFUS vary by country and indication; the technology is marketed for specific neurosurgical and noninvasive therapies by dedicated devices and manufacturers.