Construction and modeling of a reconfigurable MRI coil for lowering SAR in patients with deep brain stimulation implants

Laleh Golestanirad; Maria Ida Iacono; Boris Keil; Leonardo M Angelone; Giorgio Bonmassar; Michael D Fox; Todd Herrington; Elfar Adalsteinsson; Cristen LaPierre; Azma Mareyam; Lawrence L Wald

doi:10.1016/j.neuroimage.2016.12.056

Construction and modeling of a reconfigurable MRI coil for lowering SAR in patients with deep brain stimulation implants

Neuroimage. 2017 Feb 15:147:577-588. doi: 10.1016/j.neuroimage.2016.12.056. Epub 2016 Dec 21.

Authors

Affiliations

¹ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA. Electronic address: lgolestanirad@gmail.com.
² Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USA.
³ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Institute of Medical Physics and Radiation Protection, THM, Life Science Engineering, Giessen, Germany.
⁴ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
⁵ Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
⁶ Partners Neurology, Massachusetts General Hospital, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
⁷ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA.
⁸ Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA.

Abstract

Post-operative MRI of patients with deep brain simulation (DBS) implants is useful to assess complications and diagnose comorbidities, however more than one third of medical centers do not perform MRIs on this patient population due to stringent safety restrictions and liability risks. A new system of reconfigurable magnetic resonance imaging head coil composed of a rotatable linearly-polarized birdcage transmitter and a close-fitting 32-channel receive array is presented for low-SAR imaging of patients with DBS implants. The novel system works by generating a region with low electric field magnitude and steering it to coincide with the DBS lead trajectory. We demonstrate that the new coil system substantially reduces the SAR amplification around DBS electrodes compared to commercially available circularly polarized coils in a cohort of 9 patient-derived realistic DBS lead trajectories. We also show that the optimal coil configuration can be reliably identified from the image artifact on B₁⁺ field maps. Our preliminary results suggest that such a system may provide a viable solution for high-resolution imaging of DBS patients in the future. More data is needed to quantify safety limits and recommend imaging protocols before the novel coil system can be used on patients with DBS implants.

Keywords: Deep brain stimulation (DBS); Finite element method (FEM); Magnetic resonance imaging (MRI); Medical implants; Neurostimulation; Parkinson's disease; RF heating; Safety; Specific absorption rate (SAR).

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Brain / diagnostic imaging*
Computer Simulation
Deep Brain Stimulation*
Humans
Implantable Neurostimulators*
Magnetic Resonance Imaging* / instrumentation
Magnetic Resonance Imaging* / methods
Magnetic Resonance Imaging* / standards

Abstract

Publication types

MeSH terms

Grants and funding