Brain feedback: Focused ultrasound beams heat a target in the brain, while real-time images captured by the scanner give the neurosurgeon immediate feedback on the procedure.
According to the new study, all nine patients reported immediate pain relief after the outpatient procedure and were up and about soon afterward. “Two patients had a glass of Proseco [wine] with us,” says Ernst Martin, director of the Magnetic Resonance Center at the University Children’s Hospital Zurich and lead author of the study. The patients did report feeling a few seconds of tingling or dizziness, and in one case a brief headache, as the targeted tissue heated up, he says. But none experienced neurological problems or other side effects after surgery.
“This will give a lot of impetus for manufacturers of focused ultrasound equipment to get interested in the brain,” says Kassell. An experimental version of InSightec’s ultrasound device is currently being tested in five medical centers around the globe. In addition to using it with Parkinson’s patients and those who suffer other movement disorders, scientists plan to test the technology as a treatment for brain tumors, epilepsy, and stroke.
One downside of HIFU compared to the more invasive neurosurgeries performed with an electrode is that surgeons are unable to functionally test whether they have targeted the correct part of the brain. During traditional surgery for Parkinson’s, for example, the neurosurgeon stimulates the target area with the electrode to make sure he or she has identified the piece of the brain responsible for the patient’s motor problems, and then kills that piece of tissue.
“Not every functional neurosurgeon will accept this [new approach], because you cannot do a test before the lesion is made,” says Ferenc Jolensz, director of the Division of MRI and Image Guided Therapy Program at Brigham and Women’s Hospital in Boston. Jolensz and collaborator Seung-Schik Yoo are developing ways to use HIFU to modulate brain activity in a localized area, which would enable functional testing of the target area before it is destroyed. Jolensz is also studying HIFU for brain surgery and has tested the technology on four patients with brain tumors, though the results have not yet been published.