Towards safe operation of an active retinal prosthesis during functional MRI and diffusion tensor imaging

Area of Science:

• Medical device engineering
• Neuroscience
• Radiology

Background:

• The Argus II retinal prosthesis restores some vision to patients with retinitis pigmentosa.
• Assessing the safety of medical implants during advanced neuroimaging is crucial.

Purpose of the Study:

• To evaluate the operational capability of the Argus II retinal prosthesis during fMRI and DTI.
• To measure induced currents in the prosthesis to ensure patient safety during these imaging modalities.

Main Methods:

• A modified Argus II retinal prosthesis was used for current measurements.
• The prosthesis was tested within an ASTM phantom during diagnostic, fMRI, and DTI scans.
• Active electronics were adapted for in-scan operation.

Main Results:

• The Argus II maintained communication during fMRI and DTI scans, with minor interruptions during pre-scans.
• Induced current levels were consistently lower during fMRI and DTI compared to diagnostic scans.
• Measurements confirmed induced currents remained within safe limits.

Conclusions:

• Functional MRI and diffusion tensor imaging can be safely conducted with an operating Argus II retinal prosthesis.
• The study supports the combined use of Argus II and advanced neuroimaging techniques.
• This finding expands imaging possibilities for patients with retinal implants.