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MRI-Guidance Brings New Precision to Parkinson’s Treatment An MRI-guided surgical technique developed at the University of California at San Francisco (UCSF) Medical Center may bring new precision to deep-brain stimulation surgery used to treat patients with Parkinson’s disease and other motion disorders. Neurosurgeons at UCSF have been using deep-brain stimulation for more than a decade to reduce involuntary movements and improve mobility in patients with Parkinson’s disease. The procedure involves implanting a battery-operated brain stimulator electrode into movement-controlling structures in the brain. The stimulator overrides abnormal electrical patterns in those structures to reduce involuntary movement. Using the UCSF-developed ClearPoint system allows the procedure to be done under general anesthesia. In the past, patients had to remain awake during the surgery to give motor and cognitive feedback so doctors could confirm the device was placed in the right location. (Five patients had been treated with the new system when this e-newsletter was distributed.) Performing the procedure under general anesthesia is possible because the skull-mounted device utilizes real-time MR imaging, which provides a faster, more accurate, and less invasive technique. UCSF MRI physicist Alastair Martin, PhD, was involved in developing the imaging aspects of the system. (The children’s educational site EdHeads offers actual images and a virtual simulation of the procedure online, visit www.edheads.org/activities/brain_stimulation to view the images or virtually perform the procedure yourself.) The procedure is performed in a standard MRI suite instead of an operating room, allowing the scanner to produce high-resolution images of a patient’s brain in real time. The system software utilizes the images to map the best entry point and trajectory path from the surface of the skull to the target by visualizing critical structures such as blood vessels and ventricles. As the surgeon advances the device, he or she receives more real-time images to guide the probe insertion. “The software basically takes images from the MRI machine, performs an automatic recognition of all the hardware components, and provides instructions to allow very accurate aiming of the hardware,” said Philip Starr, MD, PhD, in a UCSF news report about the system. Starr is one of the developers of the ClearPoint system. The software is compatible with any diagnostic MR scanner. UCSF is also working with doctors at the Cleveland Clinic to implement the ClearPoint system there. Starr notes that the real-time imaging greatly improves the accuracy of the deep-brain procedure. In the first five cases, the distance between the intended and actual target was within 0.5 mm. It can also reduce the time needed to perform the procedure by 50%. The system will also be tested in a pediatric patient with dystonia in the coming months. The UCSF doctors noted that the system may make more children candidates for treatment by eliminating the difficulty of performing surgery on a child who is awake. — Jim Knaub is editor of Radiology Today. |
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