Ictal ECD-SPECT differentiates between temporal and extratemporal epilepsy: confirmation by excellent postoperative seizure control

We investigated whether ictal single photon emission computed tomography (S PECT) with Tc-99(m)-ethyl cysteinate dimer (ECD) could differentiate betwee n temporal (TE) and extratemporal epilepsy (ETE) in 30 consecutive patients (n = 21 for TE, n = 9 for ETE), all of whom had excellent postoperative se izure control (class I according to Engel's classification). Ictal SPECT sh owed isolated temporal hyperperfusion in 90% (19 out of 21) of the TE patie nts and normal perfusion in two patients. All the ETE patients had ictal SP ECT findings consistent with extratemporal seizure onset. The sensitivity o f ictal ECD-SPECT for correct localization of the seizure onset zone was 80 % in all patients, 86% in TE patients and 66% in ETE patients. Although ict al ECD-SPECT has a lower sensitivity in ETE than in TE, it can be used to c learly distinguish between TE and ETE. It provides non-invasive imaging inf ormation for use in further diagnostic and treatment strategies in patients with drug-resistant focal epilepsy. ((C) 2001 Lippincott Williams & Wilkin s).