Magnetic resonance imaging in 120 patients with intractable partial seizures: a preoperative assessment

Abstract

The aim of this study was to describe magnetic resonance imaging (MRI) findings in patients with medically intractable epilepsy and to compare different magnetic resonance (MR) sequences in order to establish a dedicated and shorter scan time imaging protocol of choice. One hundred and twenty patients with seizures that were refractory to medical treatment were assessed by MRI with spin-echo (SE) T1, fast spin-echo (FSE) T2, fluid-attenuated inversion recovery (FLAIR), inversion recovery (IR) and contrast-enhanced T1 SE sequences. Pathological scans were acquired in 78 patients. Hippocampal sclerosis was detected in 30 patients (25%), cerebral, tumoral, mass lesions in 12 patients (10%), vascular malformations in nine patients (7.5%), cortical infarcts in eight patients (6.7%), cerebral infections in four patients (4.2%) and developmental disorders in 15 patients (12.5%). The most common location of the lesions was the temporal lobe (60%). Coronal, thin (slice thickness 4-5 mm) images have proven to be the most useful in the assessment of the hippocampus. FLAIR and IR are particularly useful in the detection of lesions abutting cerebrospinal fluid (CSF) spaces and developmental disorders, respectively, while T1 SE sequences before and after the intravenous administration of gadolinium offer great facility in identifying space-occupying lesions and infections. MRI is the most important diagnostic tool for the assessment of epileptogenic foci, thus playing the primary role in indicating the type of treatment to be applied.

Structural Abnormalities in Patients with Insular/Peri-insular Epilepsy: Spectrum, Frequency, and Pharmacoresistance

“…For example, typical epileptogenic lesions diagnosed in patients with temporal lobe epilepsy are hippocampal atrophy/sclerosis, dysembryoplastic neuroepithelial tumors, gangliogliomas, postherpetic encephalitic gliosis, and posttraumatic encephalomalacia. 2,8,9 Until now, little was known about the epileptogenic lesions associated with IPICE. In our study, 13 patients (27%) with IPICE manifested tumors, 8 of whom had low-grade gliomas.…”

ACR Appropriateness Criteria® Seizures-Child

“…Studies have shown that in this clinical scenario, MRI has a sensitivity of 84% with specificity of 70%, whereas the sensitivity of CT is approximately 62% [45]. MRI is particularly useful in the evaluation of mesial temporal sclerosis and cortical abnormalities that may be the cause of refractory seizures [46,47]. The data are limited on the additional value of specialized MRI sequences, such as diffusion tensor imaging, which may help to improve specificity in localization of the epileptogenic lesion in cases where conventional structural MRI is nonlesional [48].…”

Diffusion Tensor Imaging Shows More Extensive White Matter Changes in Frontal than in Temporal Lobe Epilepsy

“…Epilepsy is a common neurological disease, affecting 0.5%-1% of the population, being refractory to medical therapy in 15%-30% of cases, in some of whom, neurosurgical treatment can be superior to long-term drug treatment, (Lefkopoulos A, Haritanti A, Papadopoulou E, Karanikolas D, Fotiadis N, Dimitriadis AS, 2005;Wiebe S, Blume WT, Girvin JP, Eliasziw M., 2001) especially in temporal lobe epilepsy (TLE) which is the most common form of focal epilepsy refractory to medical therapy in adults. (Engel J Jr., 2001) Patients with frontal lobe epilepsy (FLE), however, have a poorer outcome.…”