MRI compatibility is a critical safety and clinical consideration for implanted BCI devices. Magnetic resonance imaging uses strong magnetic fields (1.5-7 Tesla) and radiofrequency (RF) energy to produce diagnostic images of the brain and body. Implanted devices containing metal, electronics, or conductive elements can interact dangerously with MRI fields — generating heating, mechanical forces, electrical interference, and image artifacts.

MRI Safety Classifications

The FDA and ASTM International define three MRI safety categories:

  • MR Safe: The device poses no known hazard in any MRI environment. Typically reserved for devices made entirely of non-metallic, non-conductive materials.
  • MR Conditional: The device can be safely scanned under specific, defined conditions (e.g., only at 1.5T, only with specific coils, specific absorption rate limits). Most implanted neurotechnology devices aim for MR Conditional labeling.
  • MR Unsafe: The device poses unacceptable risks in any MRI environment. Patients with MR Unsafe implants cannot undergo MRI.

Risks of MRI with Implants

  • RF heating: Conductive leads and electrodes can act as antennas, absorbing RF energy and converting it to heat. Electrode tip heating can damage surrounding neural tissue.
  • Magnetic force: Ferromagnetic materials experience translational force and torque in the MRI field, potentially displacing the implant.
  • Induced currents: Time-varying magnetic fields (gradient coils) can induce currents in conductive loops, potentially causing unwanted stimulation or device damage.
  • Image artifacts: Metal components create signal voids and distortions in MRI images, potentially obscuring brain anatomy near the implant.

BCI Device Status

Most current BCI devices have limited MRI compatibility:

  • Utah Array + CerePort: MR Conditional under restricted conditions (1.5T only, limited SAR). The titanium pedestal creates substantial imaging artifacts near the implant.
  • NeuroPace RNS: MR Conditional at 1.5T with specific conditions.
  • DBS systems: Modern DBS systems (Medtronic Percept, Abbott Infinity) are MR Conditional at 1.5T; some at 3T under restricted conditions.
  • Neuralink N1: MRI compatibility status has not been publicly detailed as of early 2026.

Clinical Importance

MRI is the primary diagnostic imaging modality for neurological conditions. A patient with an implanted BCI who develops a new neurological symptom (stroke, tumor, infection) may need an MRI for diagnosis. If the implant is MR Unsafe, the patient is denied access to this essential diagnostic tool. MRI compatibility is therefore a practical clinical requirement — not merely a regulatory checkbox — for BCI devices intended for long-term use.