Prisma MRI and MEG Leading to a Successful Frontal Lesionectomy in a Medically Refractory Epilepsy Patient
Abstract number :
3.31
Submission category :
9. Surgery / 9A. Adult
Year :
2021
Submission ID :
1826088
Source :
www.aesnet.org
Presentation date :
12/6/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:51 AM
Authors :
Erin Dennis, MD - University of Nebraska Medical Center; Joseph Menousek, MD – Department of Neurosurgery – University of Nebraska Medical Center; Olga Taraschenko, MD, PhD – Department of Neurological Sciences – University of Nebraska Medical Center; Aviva Abosch, MD, PhD – Department of Neurosurgery – University of Nebraska Medical Center; Matthew White, MD – Department of Radiology – University of Nebraska Medical Center; Aditya Vuppala, MD – Department of Neurological Sciences – University of Nebraska Medical Center
Rationale: Findings of a well-defined focal lesion on brain imaging in patients with medically refractory frontal lobe epilepsy (FLE) who undergo epilepsy surgery provides a better chance of achieving seizure freedom compared to patients who have no identifiable lesion. A high resolution Prisma MRI has been introduced recently to uncover lesions previously not identified with existing imaging modalities including conventional 3T MRI. Prisma MRI is a superior imaging technology due to a greater number of channels in the coils (64) and faster, stronger gradients leading to an increase in the signal to noise ratio and a better resolution. The utility of this novel MRI technology for presurgical evaluation of medically refractory FLE patients have not been formally evaluated. We report a case of a patient with focal epilepsy and poorly-defined seizure focus on intracranial EEG who had a successful identification of a new frontal lobe lesion using the Prisma MRI and underwent a lesionectomy leading to seizure freedom.
Methods: A 22-year-old male with refractory FLE who was being evaluated for epilepsy surgery underwent conventional 3T MRI that revealed a focus consistent with a transmantle sign in the posterior mesial frontal area and noninvasive EEG that captured seizures emanating from the left frontal region. Magnetoencephalography (MEG) demonstrated multiple dipoles in the left anterior frontal area that were significantly more anterior to the area of signal intensity change identified on the conventional 3T MRI. Using these data, an intracranial stereo EEG (sEEG) was performed with depth electrodes implanted in the areas highlighted on the MRI and MEG including the left anterior frontal (LOF electrode) region.
Results: Multiple seizures captured during the recording had brief electrographic changes in the LOF electrode preceding the clinical onset, thereby leading to the conclusion that ictal onset zone was adjacent to but not overlapping with the area sampled with the LOF electrode. An attempt to implant additional electrodes in the area of interest did not yield a precise delineation of the ictal onset zone. The Prisma MRI that became available after the completion of sEEG uncovered a linear lesion extending from the left anterior frontal cortex to the frontal horn of the lateral ventricle; this lesion was not visualized on the previous 3T MRI. Retrospectively, this lesion was noted to be concordant with MEG dipoles and was immediately adjacent to the LOF electrode. The lesionectomy performed using these data has resulted in seizure freedom reported at 6 months after resection. The pathology of the resected specimen revealed focal cortical dysplasia type 2.
Conclusions: This case describes the successful evaluation and surgical treatment of a patient with medically refractory FLE following the inclusion of Prisma MRI in the presurgical assessment and planning. Further studies are needed to determine the utility of this method in presurgical evaluation for medically refractory FLE.
Funding: Please list any funding that was received in support of this abstract.: None.
Surgery