Performing Functional Magnetic Resonance Imaging in Patients With Parkinson’s Disease Treated With Deep Brain Stimulation Paula R. Arantes, MD, PhD, 1 Ellison F. Cardoso, MD, 1 Maria A ˆ . Barreiros, 1 Manoel J. Teixeira, MD, PhD, 2 Ma ´rcia R. Gonc ¸alves, MD, PhD, 3 Egberto R. Barbosa, MD, PhD, 3 Sukhi Shergill Sukwinder, MD, PhD, 4 Claudia C. Leite, MD, PhD, 1 and Edson Amaro, Jr., MD, PhD 1,4 * 1 Department of Radiology, University of Sa ˜o Paulo Medical School, Sa ˜o Paulo, Brazil 2 Department of Neurosurgery, University of Sa ˜o Paulo Medical School, Sa ˜o Paulo, Brazil 3 Department of Neurology, University of Sa ˜o Paulo Medical School, Sa ˜o Paulo, Brazil 4 Department of Psychological Medicine, IoP, King’s College, London, United Kingdom Abstract: Deep brain stimulation (DBS) is a relatively novel treatment in advanced Parkinson’s disease (PD). Functional magnetic resonance imaging (fMRI) is a useful technique for examining the effects of DBS both within the basal ganglia and its cortical connectivity. There are technical difficulties in im- aging patients with PD, and the DBS itself can generate image artifacts. We describe aspects related to optimizing the fMRI acquisition parameters in patients with DBS and the results of sensorimotor activation tasks performed by four PD patients during hand, foot, and tongue movements, both before and after DBS implant. Provided that all safety conditions are followed, it is possible to perform fMRI in patients with PD and DBS. The standard DBS surgical procedure has to be slightly mod- ified in order to reduce image artifacts. The event-related de- sign provided increased power to detect sensorimotor cortex and basal ganglia activation. © 2006 Movement Disorder So- ciety Key words: functional magnetic resonance imaging; Parkin- son’s disease; deep brain stimulation; block design; event- related design; brain activation; subthalamic nucleus Deep brain stimulation (DBS) has made a major im- pact in the therapy of patients with advanced Parkinson’s disease (PD). 1 An electrode is implanted in the internal segment of the globus pallidus (GPi) or the subthalamic nucleus (STN) and connected with an electrical genera- tor, set with optimized parameters: voltage, frequency, and pulse. Stimulation of the STN is reported to improve tremor, rigidity, bradykinesia, and gait disturbances in PD. 2 While the mechanism of action of DBS remains poorly understood, the success of this technique in the treatment of movement disorders is bringing into ques- tion traditional concepts of the organization of the basal ganglia and spearheading a reexamination of the nature and function of brain areas involved in the control of movement. New techniques, such as functional magnetic reso- nance imaging (fMRI), can help in mapping neuronal circuits in order to better understand the effects of DBS in parkinsonian patients before and after electrode im- plantation. In order to circumvent the technical problems related to the presence of the electrodes in the brain tissue, it is necessary to examine the steps involved in DBS implantation and minimize the sources of image artifacts accordingly. Magnetic resonance imaging (MRI) scanning proce- dure can result in heating, magnetic field interactions, induced currents, and the functional disruption of a DBS system in patients with such devices implanted. 3 This limitation poses important safety questions, although some groups have experienced no side effect when fol- lowing all safety procedures and advices. 3–8 On the other hand, the type of imaging technique used to acquire images in fMRI studies (i.e., echo planar) is more prone *Correspondence to: Dr. Edson Amaro, Jr., Al Lorena, 280/113 02414-000, Sa ˜o Paulo, SP, Brazil. E-mail: eamaro@usp.br Received 23 January 2004; Revised 17 October 2004 and 24 Sep- tember 2005; Accepted 21 December 2005 Published online 2 May 2006 in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/mds.20912 Movement Disorders Vol. 21, No. 8, 2006, pp. 1154 –1162 © 2006 Movement Disorder Society 1154