MR imaging evaluation of seizures.

It is imperative for a radiologist to determine the type of seizure a patient has prior to magnetic resonance (MR) imaging to optimally provide the clinician with the information he or she requires. Specifically, complex partial seizures require evaluation of the frontal lobes and the hippocampus (for mesial temporal sclerosis). These are best evaluated with fluid-attenuated inversion recovery (FLAIR) imaging; the use of intravenously administered contrast material is not required. Other types of chronic seizures are best evaluated with nonenhanced FLAIR or T2-weighted imaging for low-grade tumors, vascular malformations, gliosis after infarction, inflammation, or trauma. The presence of new-onset seizures in an adult or the worsening of chronic seizures warrants T2-weighted or FLAIR imaging and gadolinium-enhanced T1-weighted imaging (to look for primary or metastatic tumors, infections, or inflammatory lesions). If available, echo-planar diffusion imaging should be used also (to look for acute infarcts).