Validation of an automatic dose injection system for Ictal SPECT in epilepsy.

UNLABELLED: The purpose of our study was to evaluate the performance and clinical usefulness of an automated injector system (AIS) that administers an automated injection for ictal SPECT after calculating the volume of tracer to be injected over time. METHODS: To test the AIS, repeated injections were performed at different times after tracer preparation. The clinical study consisted of 56 patients with drug-resistant, complex partial seizures. Tracer for ictal SPECT was injected using automated injection in 27 patients and manual injection (MI) in the remaining 29. Injection time (T(I)) was measured in seconds from seizure onset to the end of volume injection. The SISCOM (Subtraction Ictal Spect Co-registered to MRI) procedure was used to locate the epileptogenic seizure focus with SPECT. The definition of seizure focus was made by consensus of the epilepsy unit using conventional diagnostic methods. RESULTS: During the experimental phase, there were no system failures, and the error in injected doses when using automated injection was lower than with MI. During the clinical phase, T(I) using manual injection was 41 s with a range of 14-103 s, compared with an AIS average of 33 s with a range of 19-63 s (P < 0.05). Ictal SPECT and SISCOM successfully localized the seizure focus in 21 of the 27 patients (78%) by AIS and in 19 of the 29 patients (65%) by MI (P = 0.14). Furthermore, nursing staff found the AIS method more convenient than the MI method. CONCLUSION: An AIS can improve the quality of work of the nursing staff in the neurology ward and allow a finer adjustment of the injection dose. Early results using an AIS would indicate a reduction in injection time and improved SPECT accuracy.

Functional neuroimaging in startle epilepsy: involvement of a mesial frontoparietal network.

PURPOSE: Startle epilepsy is a rare form of epilepsy with seizures triggered by unexpected stimuli. Previous studies have suggested the participation of several brain regions, such as the supplementary motor area (SMA) or the mesial aspect of the frontal and parietal lobes in the generation of startle epilepsy. However, how these brain regions interact with each other during seizures remains largely unknown. The aim of this study was to get insight into brain structures involved in startle-induced seizures using an approach with functional neuroimaging. METHODS: Four patients with startle epilepsy secondary to unexpected sounds were studied. All of them underwent a presurgical evaluation including ictal-single-emission computed tomography/subtraction ictal SPECT coregistered to MRI (magnetic resonance imaging) (SPECT/SISCOM). We searched for areas with ictal changes of perfusion higher than two standard deviations (2 SD) above the reference. In one patient, a fluorodeoxyglucose-positron emission tomography (FDG-PET) and an ictal electroencephalography-functional MRI (EEG-fMRI) were also performed. In this patient, the results of FDG-PET and sequential analysis of EEG-fMRI were compared to SISCOM. KEY FINDINGS: All the patients had their typical startle-induced seizures, consistent with bilateral asymmetric tonic seizures. Ictal-EEG pattern was located over the mesial centroparietal region in all of them. In three of four patients, a significant hyperperfusion over the mesial frontocentral region was seen, involving the SMA, the perirolandic region, and the precuneus. In one patient, who had a congenital bilateral perisylvian polymicrogyria, it was located over the lateral perirolandic region. 18F-FDG-PET results in the patient in whom it was done, were concordant with SISCOM findings. Ictal EEG-fMRI showed an initial activation located over the precuneus, SMA, cingulate gyrus, and the precentral/perirolandic area. SIGNIFICANCE: By using a functional neuroimaging approach we have found that startle-induced seizures could be generated by the interaction of a frontoparietal network located over the mesial surface of the brain.