PreOp changes to Persyst ESI supported by Epilog

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After years of development, validation and significant user feedback of our PreOp technology for interictal spike localization, we felt it’s the right time to go to the next level.
Integrated in the clinical workflow, possibility of manual spike marking, easy return to raw EEG, quick data upload,… This is all possible in Persyst ESI Powered by Epilog, an integrated version of our ESI service in the EEG software of Persyst. The launch is expected in April 2021.

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We would like to assure you that in the meantime nothing changes for you, the PreOp solution is continuing as normal. Of course, if you are interested in getting a demo and testing the new solution for free, please let us know.

Electrical source imaging can provide valuable insights in the preoperative evaluation for refractory epilepsy. However, such advanced EEG analysis is a time-consuming and labour-intensive process. Epilog PreOp offers an efficient and clinically validated alternative with a sensitivity of 88% after interpretation by an expert.


Automated spike detection

Epilog PreOp uses accurate and clinically validated techniques for spike detection and clustering.

3D patient-specific source localization

A patient-specific head model that includes six tissue types (scalp, skull, CSF, air cavities, gray and white matter) is generated from your patient’s MRI. The distrinction between gray and white matter and modeling is crucial for the most accurate localization of epileptic activity in 3D within the brain. This is not implemented in other software packages.

Concise online report and 3D-viewer

The results of the analysis are provided in a report that contains all relevant information. The reconstructed epileptic activity can also be visualized using our 3D viewer, or exported to the PACS system of your hospital.


The complete Epilog PreOp processing pipeline was validated on typical clinical long-term EEG recordings (25 electrodes). The results are depicted below and show that a semi-automated interpretation of electrical source imaging generated by our pipeline obtains higher sensitivity than MRI, SPECT and PET during the preoperative evaluation.


*Baroumand, Amir G., et al. “Automated EEG source imaging: A retrospective, blinded clinical validation study.” Clinical Neurophysiology 129.11 (2018): 2403-2410.


Patient specific MRI
Check a typical report
Patient specific MRI
Check a typical report
Questions about the right product for you?


PreOp used in clinical routine

Ghent University Hospital

At Ghent University Hospital patients go through an extensive work-up before the possibility of epilepsy surgery is discussed. All patients have long-term video-EEG-monitoring (usually 7 days), 3T MRI, FDG-PET and neuropsychological testing.

Geneva University Hospital

At the University Hospital of Geneva, the presurgical evaluation of refractory epilepsy patients contains a battery of clinical tests: structural MRI, video-EEG monitoring, interictal PET, ictal SPECT, neuropsychological examination, patient history and high-density EEG.