# Crucial Insights from Interictal 99mTc–ECD Brain Perfusion SPECT in Enhancing Pediatric Epilepsy Diagnosis and Management

## TL;DR

This study shows that 99mTc-ECD brain SPECT can help diagnose and manage drug-resistant epilepsy in children when MRI and EEG are not enough.

## Contribution

The study demonstrates the diagnostic value of interictal 99mTc-ECD SPECT in pediatric drug-resistant epilepsy when conventional methods are inconclusive.

## Key findings

- Medial temporal lobe hypoperfusion was observed in all patients.
- SPECT findings were concordant with EEG in 26.67% of cases.
- Combining SPECT with clinical and electrophysiological data improves diagnosis and management of pediatric DRE.

## Abstract

Epilepsy, a prevalent neurological disorder in children, manifests through recurrent seizures due to abnormal neuronal activity. Drug-resistant epilepsy (DRE) is a significant clinical challenge, often necessitating advanced diagnostic approaches to optimize treatment strategies. Single photon emission computed tomography (SPECT) imaging, particularly using the radiopharmaceutical 99mTc-ethyl cysteinate dimer (99mTc-ECD), offers potential in localizing epileptogenic zones, especially when conventional magnetic resonance imaging (MRI) and electroencephalography (EEG) findings are inconclusive. This study was performed to evaluate patterns of brain perfusion using 99mTc-ECD SPECT in children aged < 18 years diagnosed with DRE, and to correlate these findings with clinical evaluations, MRI, and video EEG reports.

A descriptive observational study was conducted over 18 months on 60 children with DRE. Each participant underwent a detailed clinical history, video EEG, MRI, and a 99mTc-ECD brain perfusion SPECT scan. The SPECT images were analyzed visually and semiquantitatively for hypoperfusion and hyperperfusion patterns. Data were cross-referenced with clinical lateralization, MRI findings, and EEG results to assess concordance.

A total of 60 children with DRE and mean age of 11.02 + 3.8 years (1–< 18 years) including 16 (26.7%) female and 44 (73.3%) male patients were prospectively analyzed. Forty of 60 (66.7%) patients had normal MRI brain study and 23/60 (38.3%) patients had normal EEG records. Medial temporal lobe hypoperfusion was seen in all patients, while 16/60 (26.67%) patients had additional foci of hyperperfusion in left frontal lobe and 14/60 (23.3%) patients in right frontal lobe. Thirty-six of 60 (60%) patients had involvement of one hemisphere, 24/60 (40%) showed perfusion abnormalities in both hemispheres. Moderate to severe hypoperfusion was seen in left temporal lobe in 39/60 (65%) patients whereas 30/60 (50%) patients showed moderate to severe hypoperfusion in right temporal lobe. SPECT findings were concordant with EEG in 16/60 (26.67%) of cases and concordant MRI, EEG, and 99mTc-ECD was seen in 5/60 (8.3%) cases.

99mTc-ECD brain perfusion SPECT is a valuable diagnostic tool in the comprehensive evaluation of pediatric DRE. It enhances lateralization and localization of epileptogenic zones, especially when conventional imaging is nondiagnostic. Interictal brain SPECT, is easily available, indispensable, and complementary in diagnosis. Combining it with clinical and electrophysiological evaluation can significantly improve clinical outcome and management of patients with DRE.