The idea of using long, sharp metallic instruments to enter the anterior cranium and frontal lobes to “treat” certain disorders conjures up images of the infamous frontal lobotomies performed in Europe and the United States from the 1930s to 1950s. Over the last decade, however, metallic leads that traverse the frontal lobes have taken on a new direction and purpose. Deep brain stimulation (DBS) has become an amazing way of treating a handful of disorders, which otherwise would lead to continued morbidity and likely mortality. Movement disorders, including Parkinson disease, essential tremor, and dystonia were the first set of diseases for which the Food and Drug Administration approved DBS, with additional investigational indications such as obsessive-compulsive disorder and treatment-refractive major depressive disorder (MDD) being studied currently.

Imaging for DBS offers neuroradiologists a unique opportunity to be involved in the screening, presurgical planning, and postsurgical evaluation of patients with DBS. Emory University is a major treatment center for DBS in patients with movement disorders. We have partnered with our clinical colleagues in neurosurgery and neurology to offer pre- and postsurgical MR imaging protocols for patients with DBS with movement disorders. Patients being considered for potential DBS are also evaluated with a separate screening MRI protocol. Additionally, we are working with our clinical colleagues to formulate useful, detailed DBS dictation templates as part of a systems-based practice project, led by one of our neuroradiology fellows.

Much of the imaging for DBS is done by MRI and focuses predominantly on identifying the major nuclei targeted for lead placement, the globus pallidus interna and the subthalamic nucleus. High-resolution volumetric imaging, such as with MPRAGE sequences, is integral to providing the anatomic landscape with which direct DBS surgical targeting can be performed. Some surgeons use an indirect method, which is based on the anterior/posterior commissure line, relative to a commonly accepted brain

atlas system (Talaraich space). At Emory, the neurosurgical team uses a “homemade” software program called Onetrack, which combines both direct and indirect methods to provide a roadmap for the surgeon to use intraoperatively in patients with movement disorders.

A 1.5T MR scanner is used for intraoperative guidance of the leads. Postoperative MR evaluation looks mainly for lead placement, immediate complications (ie, hematoma, acute infarction, ventricular misplacement), and late complications (ie, lead fracture, lead migration, infection, late infarction). CT can be useful to see lead integrity and any extracranial complications of lead placement (ie, collections or lead fracture).

Emory is also starting to be a center for DBS in patients with MDD refractory to medical therapy and electroconvulsive therapy. We are collaborating with our colleagues in psychiatry, neurology, and neurosurgery to identify optimal imaging sequences and protocols for preoperative direct targeting and postoperative assessment.

As newer indications for DBS emerge, I’m confident the role of the neuroradiologist will be of greater value to the patient clinical care team. At this year’s ASNR Annual Meeting in San Diego, our group at Emory submitted an educational exhibit about the imaging of DBS, which we hope readers of this digest were able to see. Please look for more work on the imaging of DBS from us in the near future.

Featured image modified from: Dormont D, Seidenwurm D, Galanaud D. Neuroimaging and Deep Brain Stimulation.