Resting functional MRI with default mode-based functional connectivity analysis for localization of epileptic activity / 中华外科杂志

<p><b>OBJECTIVE</b>Using the functional connectivity analysis based on the underlying neurophysiological characteristic that epileptic discharges can induce change of brain default mode, to develop a technique for epileptogenic localization using functional MRI (fMRI) without simultaneous electroencephalography (EEG).</p><p><b>METHODS</b>A data-driven method that jointly employed independent component analysis and functional connectivity analysis was used for the resting functional MRI data analysis of 12 focal epileptic patients. The independent components were ranged according to the coefficients of the negative correlation between independent component time course and the signal temporal course in the region of posterior cingulate cortex. The results were comparatively studied with simultaneous EEG-fMRI.</p><p><b>RESULTS</b>In the 10 successful results from 12 patients underwent EEG-fMRI examination, the outcomes of eight subjects were concordant with pathological foci. While the results of all 10 patients processed by data-driven method were concordant with pathological foci, besides the other patients who failed to perform EEG-fMRI examination. Meanwhile, the default mode was well mapped in all patients.</p><p><b>CONCLUSIONS</b>The default mode-based functional connectivity analysis can localize the epileptogenic foci effectively without simultaneous EEG, besides to detect the default mode of epileptic patients.</p>

Detection of focal epileptic activity using combined simultaneous electroencephalogram-functional MRI / 中华放射学杂志

Objective To observe the brain activation of interictal epiletiform discharges(IEDs) and to localize the epileptogenic foci of epilepsy.Methods The electroencephalogram(EEG)and functional MRI data of 12 focal epileptic patients were acquired using a combination of EEG and functional MRI simultaneously.The IEDs onset time detected with EEG were set as the time parameters in an event- related paradigm of functional MRI analysis.The spatial and temporal characters of IEDs activation were analyzed in detail.In order to confirm the consistency of this method,all patients were scanned repeatedly and the results were correlated with clinical evaluation.Results Of the 12 patients,valid data from EEG- fMRI were obtained from 10 patients in a total of 18 sessions..Compared with the structural foci,the epileptic foci localization results of eleven sessions were good,five sessions were fairly good,and two sessions were poor.The results obtained from six patients in two separate sessions were concordant.respectively.Moreover,thalamic activation was detected in ten sessions,cerebellar activation was detected in all sessions,and the deactivation was found in the default mode loci in nine sessions. Conclusion The method of performing EEG and fMRI simultaneously can potentially be a useful tool in epilepsy research.