Correlation between Provoked Ictal SPECT and Depth Recordings in Adult Drug‐Resistant Epilepsy Patients

Abstract

Summary:Purpose: To correlate ictal hyperperfusion singlephoton emission computed tomography (SPECT) area during provoked seizures to the epileptogenic zone (EZ), as defined by depth recordings in adult drug-resistant patients.Methods: We included in the study eight drug-resistant epilepsy patients, subjected to both noninvasive and invasive (stereo-electroencephalography, SEEG) presurgical evaluation in the Epilepsy Surgery Center of the Catholic University in Rome, from 2001 to 2003. All patients were subjected to interictal and provoked ictal SPECT scans during scalp video-EEG monitoring. The ictal hyperperfusion area assessed by visual image analysis and, when possible, by statistical parametric mapping (SPM), was compared with the EZ, as assessed by SEEG, to define whether they colocalized.Results: For each provoked seizure, we obtained a SPECT hyperperfusion area. In five patients, the SPECT hyperperfusion area was included in the EZ as assessed by SEEG. The effectiveness of provoked SPECT was confirmed by comparison with SEEG data, SPM analysis (four patients), and spontaneous ictal SPECT (two patients). Our data were obtained in adult drugresistant epilepsy patients whose EZ was either located in or extended to extratemporal regions in all but two patients.Conclusions: Provoked ictal SPECT confirmed its efficacy and accuracy in the presurgical evaluation because of the colocalization to the EZ. Although the low number of patients precluded any statistical correlation with the surgical outcome, it is worth pointing out that the five patients in whom the hyperperfusion area was included in the EZ showed very satisfactory results.

Refinement of a model of acquired epilepsy for identification and validation of biomarkers of epileptogenesis in rats

“…It is generally assumed that a decrease in seizure threshold is a hallmark of epileptogenesis [47], indicating cortical hyperexcitability, but seizure threshold is difficult to assess in humans. However, Barba et al [48,49] used PTZ to provoke seizures during presurgical evaluation in patients with intractable epilepsy and reported that PTZ is safe for this purpose. An alternative method of determining alterations in brain excitability following brain insults in both animal models and patients is cortical excitability measures on transcranial magnetic stimulation (TMS) [50][51][52].…”

Contribution of EEG/fMRI to the definition of the epileptic focus

“…23 Therefore, it may be concluded that temporal neocortical spikes with maximum mesial responses are indeed dependent on a more intense neuronal discharge in mesial temporal structures. In the third patient with MTS with a neocortical activation, we could infer that the main epileptogenicity was neocortical and not mesial.…”

Neuroimaging of epilepsy

“…Even in patients with electrophysiologic-verified epileptogenic lesions, such as HS or other focal pathology, some do not benefit from surgery. Other patients who fail surgery may in fact have temporal plus epilepsy, with an epileptogenic network that extends into other cerebral lobes (Barba et al, 2007; Bertram, 2009). Ictal SPECT scans in MTLE show an increase in tracer uptake in the medial temporal region, cerebellum, thalamus, insula, and putamen.…”