Mri Evaluation of Seizures

Abstract

Background Seizures are a complex neurological event that are caused by a wide range of structural, vascular, infectious, developmental, neoplastic and degenerative abnormalities of the brain. The presence of an underlying structural substrate is crucial for etiological classification, therapeutic planning, prognosis and, in some patients, for epilepsy surgery. Magnetic resonance imaging (MRI) has high soft-tissue contrast, multiplanar ability and sensitivity for abnormalities that may be occult on other imaging modalities. Modern epilepsy imaging focuses on specific structural sequences including high-resolution 3D T1 weighted sequences, fluid-attenuated inversion recovery (FLAIR) and high-resolution coronal T2 weighted sequences taken at right angles to the axis of the hippocampus.
Objective The study aimed to identify the type and prevalence of structural MRI abnormalities in patients with clinically established seizures, explore the correlation between these abnormalities, age, sex and seizure type and to establish the main categories of underlying etiology as the cause of MRI abnormalities.
Materials and Methods The study was a prospective, time-bound study of two years duration from June 2024 till may 2026. The total number of patients with clinical seizures was 110 examined at the affiliated teaching hospitals. There was no restriction on the age and sex of patients. Those who had contraindications to MRI, or severe claustrophobia or could not give consent were excluded. MRI imaging was carried out on a 1.5-T GE system. Seizure imaging protocol included T1, T2, FLAIR, diffusion-weighted imaging with ADC, gradient-echo imaging, contrast enhanced T1 weighted imaging, and magnetic resonance angiography and magnetic resonance spectroscopy (MRS) if clinically necessary. Clinical history, seizure type, duration of illness, neurological findings and characteristics of the MRI were noted. Proportions were used for descriptive analysis.
Results Among 110 patients, 67 (61%) were male and 43 (39%) were female, giving a male-to-female ratio of 1.5:1. The combined age group of 1-30 years was the largest group with 53 patients (48.18%). Generalized tonic-clonic seizures were the most common clinical seizure type (87 patients, 79.10%). MRI was normal in 53 patients (48.18%) and abnormal in 57 patients (51.82%). The most common abnormalities were cerebral infarction with gliosis (22 patients, 20.00%), neurocysticercosis (8, 7.27%), cerebral atrophy (6, 5.45%), tuberculoma (4, 3.64%), venous thrombosis (4, 3.64%) and developmental malformations (4, 3.64%). Glioma, cavernoma, and tuberous sclerosis made up 1.82% each, and meningioma and cerebral abscess and Sturge-Weber syndrome accounted for 0.91% each. MRI was positive in 48% of the patients who had generalized tonic-clonic seizures and in 80% of those who had myoclonic seizures. The highest percent positivity was observed in seizure categories that have only one or two patients.
Conclusion About half of the patients who underwent structural MRI had abnormalities. Cerebrovascular disease was the most common etiological diagnosis, and infarction and gliosis were the most common individual MRI diagnosis. Another integral part of the imaging spectrum was infectious and developmental abnormalities. The results indicate that dedicated MRI has a diagnostic role in the evaluation of seizures and that the spectrum of the structures observed is quite wide in a hospital population in South India. Limited size of subgroups needs to be considered when interpreting small subgroups. In addition, current epilepsy imaging guidelines continue to advocate for standardized high-resolution structural MRI acquisition to enhance detection of subtle epileptogenic lesions.