The aim of this study was to evaluate the safety of 3-T MRI in patients with implanted deep brain stimulation (DBS) systems.
This study was performed in 2 phases. In an initial phantom study, a Lucite phantom filled with tissue-mimicking gel was assembled. The system was equipped with a single DBS electrode connected to an internal pulse generator. The tip of the electrode was coupled to a fiber optic thermometer with a temperature resolution of 0.1°C. Both anatomical (T1- and T2-weighted) and functional MRI sequences were tested. A temperature change within 2°C from baseline was considered safe. After findings from the phantom study suggested safety, 10 patients with implanted DBS systems targeting various brain areas provided informed consent and underwent 3-T MRI using the same imaging sequences. Detailed neurological evaluations and internal pulse generator interrogations were performed before and after imaging.
During phantom testing, the maximum temperature increase was registered using the T2-weighted sequence. The maximal temperature changes at the tip of the DBS electrode were < 1°C for all sequences tested. In all patients, adequate images were obtained with structural imaging, although a significant artifact from lead connectors interfered with functional imaging quality. No heating, warmth, or adverse neurological effects were observed.
To the authors' knowledge, this was the first study to assess the clinical safety of 3-T MRI in patients with a fully implanted DBS system (electrodes, extensions, and pulse generator). It provided preliminary data that will allow further examination and assessment of the safety of 3-T imaging studies in patients with implanted DBS systems. The authors cannot advocate widespread use of this type of imaging in patients with DBS implants until more safety data are obtained.
ABBREVIATIONSDBS = deep brain stimulation; fMRI = functional MRI; FRFSE = fast recovery fast spin echo; FSPGR = fast spoiled gradient–recalled; GRE-EPI = gradient-echo echo-planar imaging; IPG = internal pulse generator; PROBE-SV = point-resolved single-voxel spectroscopy; PVG = periventricular gray; RF = radiofrequency; SAR = specific absorption rate; STN = subthalamic nucleus; VIM = ventral intermediate.
Correspondence Francesco Sammartino, Division of Neurosurgery, Department of Surgery, University of Toronto, 399 Bathurst St., Toronto, ON M5T 2S8, Canada. email: firstname.lastname@example.org.
INCLUDE WHEN CITING Published online December 23, 2016; DOI: 10.3171/2016.9.JNS16908.
Disclosures Dr. Hodaie has received grant support from Medtronic for efforts not related to this study. Dr. Lozano is the owner of Functional Neuromodulation and has served as a consultant for St. Jude, Boston Scientific, and Medtronic.
BhidayasiriRBronsteinJMSinhaSKrahlSEAhnSBehnkeEJ: Bilateral neurostimulation systems used for deep brain stimulation: in vitro study of MRI-related heating at 1.5 T and implications for clinical imaging of the brain. Magn Reson Imaging23:549–5552005
HendersonJMTkachJPhillipsMBakerKShellockFGRezaiAR: Permanent neurological deficit related to magnetic resonance imaging in a patient with implanted deep brain stimulation electrodes for Parkinson's disease: case report. Neurosurgery57:E10632005
Medtronic: Medtronic announces FDA approval for the only full-body MR conditional deep brain stimulation systems. Medtronic NewsroomDecember92015. (http://newsroom.medtronic.com/phoenix.zhtml?c=251324&p=irol-newsArticle&ID=2121236) [Accessed October 12 2016]
MinHKHwangSCMarshMPKimIKnightEStriemerB: Deep brain stimulation induces BOLD activation in motor and non-motor networks: an fMRI comparison study of STN and EN/GPi DBS in large animals. Neuroimage63:1408–14202012
MinHKRossEKLeeKHDennisKHanSRJeongJH: Subthalamic nucleus deep brain stimulation induces motor network BOLD activation: use of a high precision MRI guided stereotactic system for nonhuman primates. Brain Stimulat7:603–6072014
RezaiARLozanoAMCrawleyAPJoyMLDavisKDKwanCL: Thalamic stimulation and functional magnetic resonance imaging: localization of cortical and subcortical activation with implanted electrodes. Technical note. J Neurosurg90:583–5901999
Saint-CyrJAHoqueTPereiraLCDostrovskyJOHutchisonWDMikulisDJ: Localization of clinically effective stimulating electrodes in the human subthalamic nucleus on magnetic resonance imaging. J Neurosurg97:1152–11662002
SarkarSNSarkarPRPapavassiliouERojasRR: Utilizing fast spin echo MRI to reduce image artifacts and improve implant/tissue interface detection in refractory Parkinson's patients with deep brain stimulators. Parkinsons Dis2014:5085762014
SpiegelJFussGBackensMReithWMagnusTBeckerG: Transient dystonia following magnetic resonance imaging in a patient with deep brain stimulation electrodes for the treatment of Parkinson disease. Case report. J Neurosurg99:772–7742003
TaylorJRWilliamsNCusackRAuerTShaftoMADixonM: The Cambridge Centre for Ageing and Neuroscience (Cam-CAN) data repository: structural and functional MRI, MEG, and cognitive data from a cross-sectional adult lifespan sample. Neuroimage[epub ahead of print]2015
ZarembaLAFDA guidance for magnetic resonance system safety and patient exposures: current status and future considerations. ShellockFG: Magnetic Resonance Procedures: Health Effects and SafetyBoca Raton, FLCRC Press2001