Authors :
Presenting Author: Muhammad Usman Khalid, MD – University of Kentucky
Julie L. Youssefi, MD – University of Kentucky
Thomas A. Pittman, MD – University of Kentucky
Farhan A. Mirza, MD – University of Kentucky
Sally V. Mathias, MD – University of Kentucky
Rationale:
Patients with MRI negative epilepsy may have significant findings on the postoperative histopathological report. Similarly, patients may have significant MRI findings but may not have significant findings on the post operative histopathological report. Identifying the cause of discordance between these two modalities is important to optimize patient outcomes and ensure the correct epileptogenic foci undergo surgical intervention.Methods:
We reviewed the electronic medical records of 234 refractory epilepsy patients who underwent surgical intervention over 20 years from 2003 to 2023 and selected those with discordant MRI finding and histopathology findings.Results:
We identified 84 patients with discordant findings. 51 patients were in the MRI negative group but had a positive histopathological report. One of these patients underwent a right temporal lobectomy due to PET showing decreased metabolism in the mesial temporal lobe and histopathology demonstrated Focal Cortical Dysplasia (FCD) grade 1 in this case, he had ILAE grade 1 on one-year follow up. The nine remaining patients demonstrated non-lesional histopathology, with two patients having meningeal inflammation, one having arterial inflammation, one having an organizing infarct, one with an edematous cortical tissue, one having non-dysplastic gyral thickening, one with polymicrogyria, and two with features of dysgenesis. In contrast, 23 patients with a positive MRI demonstrated no remarkable findings on histopathology. Three of these patients had demonstrated T2 hyperintensity with features concerning for FCD, eight had shown evidence of Hippocampal Sclerosis (HS), two had demonstrated evidence of a tumor, two had shown vascular malformations, and eight had shown unspecified lesional changes in the area of interest. One patient had demonstrated both HS and tumor on MRI.
Conclusions:
Successful outcomes after epilepsy surgery are predicated on accurate identification of epileptogenic foci and networks. As imaging methods improve, more patients are found to have a positive MRI, yet histopathology does not correlate. Identifying the reasons behind discordant findings, particularly in these cases, can be the key to understanding the limitations of different modalities. Funding: No funding was received in support of this abstract.