Spect imaging of brain lesions associated with refractory epilepsy

Abstract

About 30% of patients with epilepsy have different brain lesions. Development of refractory seizures during the course of the disease requires CT or MRI neuroimaging to detect progression, hemorrhage or tumor recurrence. Although SPECT with different radioligands is not routinely used, numerous studies report its role in the diagnosis of neoplastic and non-neoplastic brain lesions. The aim of this study was to evaluate Tc-99m HMPAO and Tc-99m MIBI uptake in brain lesions associated with intractable seizures. The clinical population included fourteen patients (eight males and six females, mean age 54±10.6) with refractory epilepsy. Brain SPECT was carried out 20 and 120 minutes after intravenous administration of 740 MBq (20 mCi) Tc-99m HMPAO or Tc-99m MIBI. Refractory simple partial and secondary generalized seizures were observed respectively, in five and nine individuals. EEG showed focus of epileptic activity in all patients. Brain lesions visualized on CT/MRI scans included twelve neoplasms, one arachnoid cyst and one brain abscess. Tc-99m HMPAO SPECT demonstrated region of hypoperfusion in nine patients with gliomas and one with brain abscess. Two cases with high-grade gliomas had an increased Tc-99m MIBI uptake. No radioisotope accumulation was seen postoperatively in a low-grade glioma and also in one benign cystic lesion. Although the mechanisms of epileptogenesis have remained unclear yet, our own results revealed that SPECT neuroimaging may be useful for the precise diagnosis, treatment strategy, and prognosis in patients with brain lesion-associated refractory epilepsy. Scripta Scientifica Medica 2007;39(1):67-70