The Role of Susceptibility-Weighted Imaging and Dedicated MRI Protocols in the Diagnostic Evaluation of Patients with Drug-Resistant Epilepsy

Background: Near one-third of epileptic cases never achieve remission, despite optimal medication use. In these patients, various surgical procedures can be helpful. However, surgical success is directly associated with the ability to localize precisely the region of seizure onset. Objectives: The goal of this study was to evaluate the role of susceptibility weighted imaging (SWI) in detecting intracerebral lesions and localizing epileptogenic zones in addition to conventional MRI with routine epilepsy protocol in drug-resistant epileptic patients. Methods: The study was carried out at an academic medical center in a major metropolitan city, and all participants underwent conventional MRI assessment with seizure protocol and SWI evaluation. Results: During the study period, 59 cases met the criteria. Thirty-four were male (57.6%) and twenty-five were female. Mean age of participants was 30 years, and mean age at the time of epilepsy onset was 11. In 50 cases (85%), there was evidence of brain abnormalities in conventional MRI and/or SWI. Brain abnormalities were also evident in conventional MRI evaluation of 47 cases (79%). In three out of twelve cases with normal conventional MRI with routine epilepsy protocol, SWI showed brain abnormalities. In 20 cases (40%), the same lateralization or localized lesions were detected in EEG and MRI. More information from SWI was reported in 13 patients (22%). In two cases, in which EEG showed evidence of partial seizures, conventional MRI showed no abnormality while SWI showed abnormal vascular cluster. In one of these two cases, caput medusa, in agreement with developmental venous anomaly, was reported. In one case, conventional MRI was normal while SWI showed evidence of cavernoma. In another patient, in addition to the lesion detectable in conventional MRI, SWI found two other lesions in agreement with cavernomas. Conclusions: Susceptibility weighted imaging can be helpful in localizing epileptogenic zones, which are not detectable by conventional MRI with routine epilepsy protocol, in patients with drug-resistant epilepsy.