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Safety of MRI in the localization of implanted intracranial electrodes for refractory epilepsy
Milad Yazdani1, Justin Reagan1, Madison Kocher1
1Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC.
Background And Purpose:
This is an observational study to evaluate the safety of magnetic resonance imaging (MRI) to localize subdural grids and depth electrodes in patients with refractory epilepsy using a 1.5 Tesla MR scanner.
Methods:
We implemented an optimized MRI protocol providing adequate image quality for the assessment of subdural grids and depth electrodes, while minimizing the specific absorption rate (SAR). We reviewed all MRI studies performed in patients with subdural grids and depth electrodes between January 2010 and October 2018. Image quality was graded as acceptable or nonacceptable for the assessment of intracranial device positioning. We reviewed the medical record and any imaging obtained after intracranial implant removal for adverse event or complication occurring during and after the procedure.
Results:
Ninety-nine patients with refractory epilepsy underwent MRI scans using a magnetization-prepared rapid acquisition of gradient echo sequence and a transmit-receive head coil with depth electrodes and subdural grids in place. Two patients underwent two separate depth electrode implantations for a total of 101 procedures and MRI scans. No clinical adverse events were reported during or immediately after imaging. Image quality was graded as acceptable for 97 MRI scans. Review of follow-up CT and MRI studies after implant removal, available for 70 patients, did not demonstrate unexpected complications in 69 patients.
Conclusion:
In our experience, a low SAR MRI protocol can be used to safely localize intracranial subdural grids and depth electrode in patients with refractory epilepsy.
Insights
Magnetic resonance imaging (MRI) is safe for localizing intracranial devices in epilepsy patients. An optimized, low specific absorption rate (SAR) MRI protocol provides adequate image quality without adverse events, ensuring safe patient monitoring.
Area of Science:
- Neurology
- Medical Imaging
- Neurosurgery
Background:
- Refractory epilepsy often requires invasive monitoring with intracranial electrodes.
- Accurate localization of these devices is crucial for effective treatment planning.
- Magnetic resonance imaging (MRI) is a key tool for visualizing intracranial structures.
Purpose of the Study:
- To evaluate the safety and efficacy of a 1.5 Tesla MRI protocol for localizing subdural grids and depth electrodes.
- To assess image quality for device visualization and minimize specific absorption rate (SAR).
Main Methods:
- Retrospective review of 101 MRI scans in 99 patients with refractory epilepsy (January 2010 - October 2018).
- Implementation of an optimized MRI sequence to balance image quality and SAR.
- Grading of image quality for device assessment and review of post-procedure records for complications.
Main Results:
- No adverse clinical events were reported during or immediately after MRI scans.
- 97 out of 101 MRI scans (96%) were graded as acceptable for assessing intracranial device positioning.
- Follow-up imaging after device removal showed no unexpected complications in 69 out of 70 patients.
Conclusions:
- A low SAR MRI protocol is safe and effective for localizing intracranial subdural grids and depth electrodes in refractory epilepsy patients.
- Optimized MRI techniques can provide adequate image quality for monitoring implanted devices.
