ObjectiveTo explore the advantages and disadvantages of using two intracranial EEG (iEEG) monitoring methods—Subdural ectrodes electroencephalography (SDEG)and Stereoelectroencephalography (SEEG), in patients with “difficult to locate” Intractable Epilepsy. MethodsRetrospectively analyzed the data of 60 patients with SDEG monitoring (49 cases) and SEEG monitoring (11 cases) from January 2010 to December 2018 in the Department of Neurosurgery of the First Affiliated Hospital of Fujian Medical. Observe and statistically compare the differences in the evaluation results of epileptic zones, surgical efficacy and related complications of the two groups of patients, and review the relevant literature. ResultsThe results showed that the two groups of SDEG and SEEG had no significant difference in the positive rate and surgical resection rate of epileptogenic zones, but the bilateral implantation rate of SEEG (5/11, 45.5%) was higher than that of SDEG (18/49, 36.7%). At present, there was no significant difference in the postoperative outcome among patients with epileptic zones resected after SDEG and SEEG monitoring (P>0.05). However, due to the limitation of the number of SEEG cases, it is not yet possible to conclude that the two effects were the same. There was a statistically significant difference in the total incidence of serious complications of bleeding or infection between the two groups (SDEG 20 cases vs. SEEG 1 case, P<0.05). There was a statistically significant difference in the total incidence of significant headache or cerebral edema between the two groups (SDEG 26 cases vs. SEEG 2 cases, P<0.05). There was a statistically significant difference in the incidence of cerebrospinal fluid leakage, subcutaneous fluid incision, and poor healing of incision after epileptic resection (SDEG 14 cases vs. SEEG 0 case, P<0.05); there were no significant differences in dysfunction of speech, muscle strength between the two groups (P>0.05). ConclusionSEEG has fewer complications than SDEG, SEEG is safer than SDEG. The two kinds of iEEG monitoring methods have advantages in the localization of epileptogenic zones and the differentiation of functional areas. The effective combination of the two methods in the future may be more conducive to the location of epileptic zones and functional areas.
ObjectiveTo explore the clinical electrophysiology, seizure symptomatology, multimodal imaging characteristics and epileptogenic zone location of the temporal -parietal -occipital junction (TPOJ) epilepsy.MethodsThe seizure symptomatology, head MRI, PET-CT and their fusion manifestations, long-range scalp video EEG monitoring results of 6 cases of TPOJ epilepsy patients from March 2015 to August 2018 were analyzed retrospectively in the Second Hospital of Lanzhou University, and the value of localization of epileptogenic zone was analyzed, and the role of multi-modal evaluation based on SEEG in localization of epileptogenic zone was discussed.ResultsThe first symptoms: 2 of 6 patients were complicated visual hallucination; 3 were head eye deflection (2 were opposite to epileptogenic focus, 1 was ipsilateral); 1 was excessive movement. EEG of scalp: the epileptogenic potentials in intermittent period were all multi -brain regions, but could be lateralized; in seizure period, the electroencephalogram was diffuse in 4 cases, without lateralization, and could be lateralized in 2 cases (1 case was the beginning of one hemisphere, 1 case was the beginning of one posterior head). Imaging findings: MRI was negative in 2 cases, post-traumatic soft focus in 2 cases, and FCD in 2 cases; after fusion of MRI and PET-CT, low metabolic areas in a large area including TPOJ could be found. Six patients were implanted with stereotactic electrodes, and the epileptogenic focus could be identified by EEG monitoring after implantation.ConclusionFor TPOJ epilepsy, the manifestations of premonitory and multimodal images at the onset of seizure can provide important clues for the lateralition of epileptogenic zone; scalp EEG and the first symptoms except premonitory can only provide reference clues; multimodal evaluation based on stereoelectroencephalogram can accurately locate the onset of seizure.
Accurate source localization of the epileptogenic zone (EZ) is the primary condition of surgical removal of EZ. The traditional localization results based on three-dimensional ball model or standard head model may cause errors. This study intended to localize the EZ by using the patient-specific head model and multi-dipole algorithms using spikes during sleep. Then the current density distribution on the cortex was computed and used to construct the phase transfer entropy functional connectivity network between different brain areas to obtain the localization of EZ. The experiment result showed that our improved methods could reach the accuracy of 89.27% and the number of implanted electrodes could be reduced by (19.34 ± 7.15)%. This work can not only improve the accuracy of EZ localization, but also reduce the additional injury and potential risk caused by preoperative examination and surgical operation, and provide a more intuitive and effective reference for neurosurgeons to make surgical plans.
For refractory epilepsy requiring surgical treatment in clinic, precise preoperative positioning of the epileptogenic zone is the key to improving the success rate of clinical surgical treatment. Although the use of electrical stimulation to locate epileptogenic zone has been widely carried out in many medical centers, the preoperative implantation evaluation of stereoelectroencephalography (SEEG) and the interpretation of electrical stimulation induced EEG activity are still not perfect and rigorous. Especially, there are still technological limitations and unknown areas regarding electrode implantation mode, stimulation parameters design, and surgical prognosis correlation. In this paper, the clinical background, application status, technical progress and development trend of SEEG-based stereo-electric stimulation-induced cerebral electrical activity in the evaluation of refractory epilepsy are reviewed, and applications of this technology in clinical epileptogenic zone localization and cerebral cortical function evaluation are emphatically discussed. Additionally, the safety during both of high-frequency and low-frequency electrical stimulations which are commonly used in clinical evaluation of refractory epilepsy are also discussed.
Epilepsy is a clinical syndrome characterized by recurrent epileptic seizures caused by various etiologies. Etiological diagnosis and localization of the epileptogenic focus are of great importance in the treatment of epilepsy. Positron emission tomography-computed tomography (PET-CT) technology plays a significant role in the etiological diagnosis and localization of the epileptogenic focus in epilepsy. It also guides the treatment of epilepsy, predicts the prognosis, and helps physicians intervene earlier and improve the quality of life of patients. With the continuous development of PET-CT technology, more hope and better treatment options will be provided for epilepsy patients. This article will review the guiding role of PET-CT technology in the diagnosis and treatment of epilepsy, providing insights into its application in etiological diagnosis, preoperative assessment of the condition, selection of treatment plans, and prognosis of epilepsy.