Functional MRI connectivity as a predictor of the surgical outcome of epilepsy

• Published in: Epilepsia (Copenhagen) Vol. 52; no. 9; pp. 1733 - 1740
• Main Authors: Negishi, Michiro, Martuzzi, Roberto, Novotny, Edward J., Spencer, Dennis D., Constable, R. Todd
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2011; Wiley-Blackwell; Wiley Subscription Services, Inc
• Subjects: Adolescent; Adult; Biological and medical sciences; Brain - blood supply; Brain - surgery; Brain Mapping; Child; Cost-benefit analysis; Data processing; EEG; EEG–fMRI; Electroencephalography; Epilepsy; Epilepsy - pathology; Epilepsy - surgery; Focal epilepsy; Functional connectivity; Functional Laterality; Functional magnetic resonance imaging; Functional neuroimaging; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Image Processing, Computer-Assisted - methods; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging - methods; Male; Medical sciences; Middle Aged; Nervous system; Nervous system (semeiology, syndromes); Neurology; NMR; Nuclear magnetic resonance; Oxygen - blood; Patients; Predictive Value of Tests; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Retrospective Studies; Sclerosis; Seeds; Seizures; Statistics as Topic; Surgery; Surgical outcomes; Treatment Outcome; Tumors; Young Adult; Functional connectivity; Nervous system diseases; Focal epilepsy; Prognosis; Epilepsy; Electrophysiology; Electroencephalography; Nuclear magnetic resonance imaging; Cerebral disorder; EEG-fMRI; Surgery; Central nervous system disease; Functional neuroimaging
• ISSN: 0013-9580; 1528-1167; 1528-1167
• DOI: 10.1111/j.1528-1167.2011.03191.x

Summary Purpose:  In planning epilepsy surgery, it is important to be able to assess the likelihood of success of surgery for each patient so that the possible risk and benefit can be properly considered. In this study, functional connectivity was investigated as a means for predicting surgical outcome from the preoperative functional magnetic resonance imaging (fMRI) of epilepsy patients. Methods:  Resting‐state simultaneous electroencephalography (EEG)–fMRI data were collected from 18 patients with intractable epilepsy before surgery and from 14 healthy subjects. For each patient, EEG‐spike correlated fMRI analysis was performed and an activation cluster that overlapped the most with the planned resection area for each patient was chosen as the seed for the functional connectivity analysis. After the functional connectivity maps were computed, laterality indices of functional connectivity were contrasted between patients who had seizures after surgeries (seizure‐recurrence group) and those who did not have them for at least a year (seizure‐free group). Key Findings:  Patients in the seizure‐recurrence group had less‐lateralized functional connectivity than patients in the seizure‐free group (t16 = 2.3, after control subtracted and Fisher transformed, p < 0.05, two‐tailed). Significance:  This study suggests the potential for using preoperative fMRI connectivity analysis as a predictive outcome measure. If confirmed by further research, a high laterality will be an important addition to the other predictors of better surgical outcome such as febrile seizures, mesial temporal sclerosis, tumors, abnormal MRI, and EEG/MRI concordance.