The decision to perform immediate brain magnetic resonance imaging (MRI) in children with their first unprovoked seizure presenting to the emergency department (ED) remains a clinical challenge. We aimed to identify clinical factors associated with the detection of epileptogenic lesions and emergent neuroimaging findings on MRI to determine the imaging necessity and urgency, respectively.

We retrospectively enrolled pediatric patients (age 0–18 years) presenting to a single institution's pediatric ED with new-onset unprovoked seizures between January 2010 and December 2023.

Among 222 included children, 84 (37.8 %) demonstrated an epileptogenic lesion, among which 18 (21.4 %) exhibited emergent neuroimaging findings. Multiple seizures at presentation ( p   <  0.001), prolonged seizures lasting ≥5 min (p  <  0.001), and developmental delay (p  <  0.001) were significantly associated with epileptogenic lesions. Classification of patients with one or more risk factors as the high-risk group showed a sensitivity of 94.0 % and specificity of 55.1 % for detecting epileptogenic lesions, and a sensitivity of 100 % and specificity of 39.7 % for emergent neuroimaging findings. In patients without any of these risk factors, only 5 of 81 patients (6.3 %) had epileptogenic lesions, and none had emergent neuroimaging findings.

Among patients with new-onset unprovoked seizures visiting the pediatric ED, those with one or more risk factors—multiple seizures, prolonged seizure duration, or developmental delay—may benefit from MRI to identify epileptogenic lesions. Our findings suggest that low-risk patients rarely have urgent lesions and emergent MRI might be deferred; however, prospective multicenter validation is needed before implementing this approach .