¹Consultant fetal medicine specialist, Davangere Scan Centre, Davangere, Karnataka, India.
²Department of Radiology, SSIMS and RC, Davangere, Karnataka, India.

*Corresponding author:Suhasini Vittal Rao, Consultant fetal medicine specialist, Davangere scan centre, Davangere, Karnataka, India. E-mail Id: drsuhasini2010@gmail.com

Copyright: © 2025 Kulkarni AM, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article Information: Submission:08/06/2025; Accepted: 02/08/2025; Published: 06/08/2025

Background: Seizures in paediatric patients are often due to structural brain abnormalities. Neuroimaging is critical for diagnosis and management.
Methods: We retrospectively reviewed the clinical and neuroimaging data of 昀椀ve pediatric patients with drug-resistant seizures. Imaging studies (CT or MRI) were analyzed to identify features that guided diagnosis and treatment.
Results: Each patient had characteristic neuroimaging findings.
Case 1: A 17-year-old female with focal seizures showed right parietal cortical thickening and a T2-FLAIR transmantle sign on MRI [Figure 1A-C], consistent with focal cortical dysplasia.
Case 2: A 15-year-old boy with infantile spasms and left hemiparesis had right hemispheric ventriculomegaly and cortical dysplasia on CT [Figure 2A-C], indicating hemimegalencephaly.
Case 3: A 13-year-old girl with a facial port-wine stain had left parietal gyriform calcifications and hemiatrophy on CT [Figure 3A-C], diagnosing Sturge-Weber syndrome.
Case 4: A 3-year-old girl with developmental delay had multiple calcified cortical tubers and subependymal nodules on CT, including a mass at the foramen of Monro (Figure 4A–C), consistent with tuberous sclerosis.
Case 5: A 1-year-old girl with new-onset seizures had isolated enlargement of the right lateral ventricle on CT (Figure 5), consistent with unilateral hydrocephalus. In each patient, imaging 昀椀ndings guided targeted management (medical therapy and, when indicated, surgical intervention).
Conclusion: Neuroimaging (MRI and CT) identified the underlying causes of these children’s refractory seizures. MRI revealed subtle cortical and white matter abnormalities, while CT clearly showed calcifications and ventricular anomalies. Recognizing these modality-specific features improves diagnostic accuracy and informs treatment planning.

Seizures are a common neurological presentation in children and can result from a variety of structural brain lesions. Advanced neuroimaging, is vital for detecting these abnormalities in patients with refractory seizures. In this series, we present five children each with drug-resistant seizures due to different etiologies: focal cortical dysplasia, hemimegalencephaly, Sturge-Weber syndrome, tuberous sclerosis, and unilateral hydrocephalus. We highlight how CT and MRI findings led to specific diagnoses and guided management in each case.

Clinical presentation: A 17-year-old female presented with a 6-month history of refractory focal seizures and intermittent dizziness, plus one day of new le leg weakness. Seizures began at age 15 with le arm clonic jerking, rightward eye deviation, and postictal confusion. Neurological exam showed mild le leg weakness; EEG was normal. No skin findings or systemic issues.

Imaging findings: A 1.5T brain MRI revealed a lesion in the right parietal cortex. Axial T2-FLAIR images showed subcortical white matter hyperintensity extending from the cortex toward the lateral ventricle (the “Transmantle sign” on (Figure1A). Coronal T2-FLAIR images demonstrated focal cortical thickening and blurring of the gray–white junction in the right parietal region [Figure 1B], along with patchy hyperintensity in the right parietal gyrus [Figure 1C]. these features indicate abnormal cortical development.

Diagnosis: Imaging findings are diagnostic of right parietal type II focal cortical dysplasia.

Management: The patient was treated with antiepileptic medications. (Cortical resection is often curative for FCD if medication fails.)

Focal cortical dysplasia (FCD) is a common cause of drug-resistant epilepsy in children, oen associated with cortical malformations. MRI is the imaging modality of choice for detection and classification.

• Cortical thickening.
• Blurring of the gray–white matter junction with abnormal subcortical architecture.
• T2/FLAIR hyperintensity in white matter, sometimes extending as a Transmantle sign [1,5]. • T2/FLAIR signal changes in gray matter.
• Abnormal sulcal or gyral patterns, segmental/lobar hypoplasia or atrophy.
• Typically, no edema, calcification, or contrast enhancement [6].

• Type I: Subtle or non-visible on MRI; may show mild blurring in subcortical U-fibers, often temporal [5,12]. • Type IIa: Cortical thickening, blurring of junction, abnormal gyral/sulcal pattern [5]. • Type IIb: Same as IIa plus a transmantle sign (seen in 94% of cases) [1,5]. • Type III: Associated with adjacent lesions (e.g., hippocampal sclerosis, tumors, vascular malformations, gliosis); imaging dominated by associated abnormality [5].

Clinical Relevance: Surgical resection of the epileptogenic cortex typically leads to good seizure control. Presence of the transmantle sign is associated with better postoperative outcomes [8].

Clinical presentation: A 15-year-old boy had a history of infantile spasms for 6 months of age, developmental delay, and persistent le hemiparesis. Neurological exam confirmed le-sided spastic weakness. There was no history of skin lesions or perinatal complications.

Imaging findings: Non-contrast CT of the head revealed marked asymmetry of the cerebral hemispheres. The right hemisphere was enlarged with severe dilation of the right lateral ventricle (monoventricle) due to blockage at the foramen of Monro and leward midline shi [Figure 2A]. The right occipital and temporal cortex appeared thinned and effaced. The right hemisphere showed diuse low-density white matter and scattered areas of calcification. The cortical sulci in the right frontal and parietal lobes were effaced and the gyri were abnormally enlarged [Figure 2B-C], suggestive of diffuse pachygyria.

Diagnosis: These imaging features—unilateral hemispheric enlargement with ventriculomegaly, cortical malformation, and contralateral shift—are diagnostic of right-sided hemimegalencephaly.

Management: The patient was treated medically with antiepileptic drugs and underwent placement of a ventriculoperitoneal shunt to relieve hydrocephalus.

Hemimegalencephaly is a rare malformation of cortical development involving hamartomatous overgrowth of one cerebral hemisphere. It accounts for ~0.2% of childhood epilepsy cases and is oen associated with developmental delay and infantile spasms [9,10].

MRI is the most sensitive modality, but CT and ultrasound can also detect key features [11]:
• Enlargement of the affected cerebral hemisphere
• Asymmetric ventriculomegaly (increased or sometimes small lateral ventricle)
• Cortical malformations: polymicrogyria, pachygyria, lissencephaly, agyria [9]
• Enlarged gyri, shallow sulci • Calvarial thickening on the affected side

• Displacement of the posterior falx to the contralateral side • Grey matter heterotopia • White matter calcifications • May be associated with developmental venous anomalies (DVAs)

Nuclear imaging (SPECT/PET) typically shows hypometabolism in the affected hemisphere [10].

• Isolated hemimegalencephaly. • Syndromic forms (e.g., with epidermal nevus, NF1, tuberous sclerosis, CLOVES) [9-11]. • Total form involves brainstem and cerebellum.

Clinical Relevance: Imaging confirms diagnosis and helps assess surgical eligibility. Hemispherectomy offers seizure control in 60% of refractory cases, though contralateral abnormalities may worsen prognosis [10]

Clinical presentation: A 13-year-old girl with a congenital portwine stain on the le side of her face presented with multiple seizures (first at 9 months of age). Neurological exam was otherwise normal. The facial capillary malformation suggested a neurocutaneous syndrome.

Imaging findings: Non-contrast cranial CT showed classic signs. Gyriform (tram-track) calcifications were present in the cortex of the left parietal lobe [Figure 3A-C]. There was marked atrophy of the left cerebral hemisphere, with cortical thinning and ipsilateral displacement of the falx [Figure 3B]. These findings reflect chronic leptomeningeal vascular malformations.

Diagnosis: The clinical and imaging findings are characteristic of left-sided Sturge-Weber syndrome.

Management: The patient was managed with antiepileptic medications to control seizures; neurosurgical intervention was not performed.

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by facial port-wine stain and leptomeningeal angiomatosis, most oen affecting the ophthalmic branch of the trigeminal nerve [13,14]. Seizures, typically refractory, occur in up to 89% of cases, oen within the first few years of life [15,16].

• CT is the initial modality of choice for identifying characteristic:
o Gyriform (“tram-track”) cortical and subcortical calcifications [22,23].
o Cerebral hemiatrophy with ipsilateral calvarial thickening.
o Enlarged choroid plexus.
o Asymmetric cavernous sinus or sinus enlargement [24].
o Dyke-Davido-Masson appearance in severe cases.
• MRI better delineates:
o Leptomeningeal enhancement on post-contrast T1 due to pial angiomatosis [15]
o T2 low signal in subcortical white matter (from calcification or accelerated myelination).
o Dilated transmedullary and deep venous systems.
o SWI/GE sequences enhance calcification detection as signal dropouts.
o MR spectroscopy may show decreased NAA [25].
• DSA findings include absent superficial cortical veins and abnormal deep venous drainage [16].

• Type I: Facial and leptomeningeal angiomas ± glaucoma • Type II: Facial angioma only • Type III: Isolated leptomeningeal angioma

Neuroimaging is critical in confirming diagnosis and evaluating seizure etiology. CT is useful for early calcification detection; MRI provides superior detail of pial angiomas and venous abnormalities. Surgical resection is rarely indicated; management focuses on seizure control and ophthalmologic assessment [13].

Clinical presentation: A 3-year-old girl with global developmental delay began having generalized seizures at 6 months of age. There were no focal neurological deficits or noted skin lesions on examination.

Imaging findings: Cranial CT revealed multiple typical TSC abnormalities. A calcified mass was noted at the le foramen of Monro, extending into the le lateral ventricle and causing mild dilation of the le ventricle [Figure 4A]. Many calcified subependymal nodules lined the walls of both lateral ventricles [Figure 4B]. The cerebral cortex contained numerous tubers seen as mixed-density lesions in the bilateral frontal and parietal lobes, with scattered calcifications [Figure 4C]. Adjacent white matter showed areas of low attenuation. These findings are classic for tuberous sclerosis complex (TSC).

Diagnosis: The imaging findings of multiple cortical tubers and calcified subependymal nodules (including a large lesion at the foramen of Monro) confirm the diagnosis of TSC, likely with a subependymal giant cell astrocytoma.

Management: The patient was treated with antiepileptic drugs. Neurosurgery was consulted regarding the foramen of Monro mass; if it enlarges, surgical resection (or medical therapy such as mTOR inhibitors) may be required to prevent obstruction.

Tuberous sclerosis complex (TSC) is a multisystem genetic

disorder characterized by hamartomatous growths affecting the brain, skin, kidneys, lungs, and heart. About 75% of affected children present with seizures [26].

Neurological (MRI/CT) • Cortical/Subcortical Tubers: Seen in ~50% in the frontal lobe; high T2, low T1 signal; may enhance in ~10% and frequently calcify aer age 2 [26]. • Subependymal Nodules: Oen calcified (88%) [31]; iso/ high T2 and high T1 signal; may resemble SEGA but distinguished by growth [32,33]. • Subependymal Giant Cell Astrocytomas (SEGA): Typically appear near foramen of Monro, show growth and strong enhancement [32,33]. • White Matter Abnormalities: Radial bands are relatively specific to TSC [34]. • Other CNS findings: Corpus callosum dysgenesis, cerebellar atrophy, infarcts, aneurysms, arachnoid cysts, and rarely, chordomas.

• Renal Angiomyolipomas (AMLs): Seen in 55–75% of cases; often bilateral and large, may lack visible fat [26,29]. • Renal Cysts, oncocytomas, and renal cell carcinomas [26,29]. • Retroperitoneal Lymphangiomyomatosis and hepatic AMLs also occur [29].

• Lymphangioleiomyomatosis (LAM) in 25–40% of females [29]; can lead to pneumothorax and chylous effusion.
• Multifocal Micronodular Pneumocyte Hyperplasia

(MMPH): Benign nodular lung lesions (rare). • Cardiac Rhabdomyomas and myocardial fatty foci [36,37].

Musculoskeletal & Skin (Radiographs/Clinical): • Sclerotic bone lesions in 40–66% of patients [26]. • Classic skin lesions include hypomelanotic macules, facial angiofibromas, shagreen patches, periungual fibromas, and forehead plaques [26,38,39].

Imaging plays a pivotal role in diagnosing and monitoring CNS and visceral manifestations of TSC. Early identification of tubers and SEGAs can guide seizure management and surgical decisions. Multimodal imaging (MRI, CT, US) is often required due to the multisystem nature of the disease.

Clinical presentation: A 1-year-old girl presented with three episodes of unprovoked focal seizures. There were no focal deficits. Birth history was notable only for twin gestation delivered by

C-section; no other complications were reported. No skin lesions were identified.

Imaging findings: Cranial CT showed marked enlargement of the right lateral ventricle with marked thinning of the adjacent right temporal lobe and effacement of cortical sulci (Figure5).
The enlarged ventricle caused a midline shi (~8 mm) to the le. No mass lesion or hemorrhage was seen. These findings indicate significant unilateral right-sided hydrocephalus.

Diagnosis: Imaging confirmed an isolated dilation of the right lateral ventricle, most likely due to congenital stenosis of the right foramen of Monro (given the absence of a tumor or hemorrhage).

Management: The patient was treated with antiepileptic medication and underwent right ventriculoperitoneal shunt placement to relieve the hydrocephalus.

Unilateral hydrocephalus is a rare condition typically resulting from agenesis or stenosis of the foramen of Monro, transient obstruction, or associated brain malformations such as forms of holoprosencephaly [40].
Imaging Features:
• CT and MRI show:
o Marked asymmetric dilatation of a single lateral ventricle
(typically right or le).
o Thinning of adjacent brain parenchyma due to mass effect.
o Effacement of cortical sulci and midline shift.

o Absence of mass, hemorrhage, or infection in idiopathic cases.
• MRI may better visualize:
o Membranous occlusion at the foramen of Monro.
o Associated cortical malformations or interhemispheric anomalies.

Accurate imaging diagnosis helps distinguish congenital obstruction from secondary causes like tumors or cysts. Management oen involves ventriculoperitoneal shunting to relieve pressure and prevent further parenchymal damage [40].

This series highlights the complementary roles of CT and MRI in pediatric seizure disorders. In all cases, imaging directly led to the specific etiologic diagnosis. MRI was essential for detecting subtle cortical malformations (e.g. FCD in (Case1), whereas CT was particularly valuable for identifying calcified lesions (Cases3 ,4) and gross hydrocephalus (Cases 2, 5). In general, MRI is the modality of choice in epilepsy due to superior so-tissue contrast, but CT is invaluable for detecting calcifications or acute changes quickly. The characteristic patterns—cortical thickening with transmantle sign for FCD, hemispheric enlargement for hemimegalencephaly, gyriform calcifications with hemiatrophy for Sturge-Weber, multiple calcified tubers for TSC, and one-sided ventricular dilation for unilateral hydrocephalus—guided our differential diagnosis and management. Early imaging led to timely interventions (e.g. shunting or surgical planning) and tailored treatment for each patient.

Disclosure: The authors have no conflicts of interest to disclose. None of the authors received outside funding for the production of this original manuscript and no part of this article has been previously published elsewhere.