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

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.