The role of brain MRI in mesial temporal lobe epilepsy

Abstract

Background: Mesial temporal lobe epilepsy is the most common form of epilepsy. Since its pathophysiological substrate is usually related to hippocampal sclerosis, the seizures are typically resistant to antiepileptic drugs and surgical treatment is considered in most patients. Defining the affected region on medical imaging is of paramount importance in this situation. The study aimed to evaluate the role of brain magnetic resonance imaging (MRI) in patients with suspected mesial temporal lobe epilepsy and its ability to reveal the responsible epileptogenic focus. Material and methods: The study included 96 patients aged 3 to 48 years old with clinical suspicion of temporal lobe epilepsy who underwent a brain MRI scan at the Medpark International Hospital in the period 25.01.2017 – 25.01.2018. The scans were performed on a Siemens Essenza 1.5 Tesla MRI scanner using a specially designed epilepsy imaging protocol (sag T1W, T2W, T2-tirm, DWI). Additional sequences (such as cor T2 FLAIR, T1 IR + contrast) were also included if required. Results: From a total of 96 patients, brain MRI revealed the potential epileptogenic region in 27 (28%) cases. The MRI findings in these patients included increased signal intensity in the region of hippocampus (23 patients), hippocampal atrophy or volume loss (19 patients), enlarged temporal horn (11 patients), smaller temporal lobe (10 patients) and collateral white matter atrophy (6 patients). Conclusions: In our study, mesial temporal sclerosis was the most common identifiable cause of seizures. Even though brain MRI features may vary, the increased hippocampal signal intensity was the most consistent finding.