Around 30% of patients undergoing surgical resection for drug-resistant mesial temporal lobe epilepsy (MTLE) do not obtain seizure freedom. Success of anterior temporal lobe resection (ATLR) critically depends on the careful selection of surgical candidates, aiming at optimizing seizure freedom while minimizing postoperative morbidity. Structural MRI and FDG-PET neuroimaging are routinely used in presurgical assessment and guide the decision to proceed to surgery. In this study, we evaluate the potential of machine learning techniques (logistic regression, support vector machines, random forests and artificial neural networks) applied to standard presurgical MRI and PET imaging features to provide enhanced prognostic value relative to current practice.
In the study cohort, 24/82 (28.3%) who underwent an ATLR for drug resistant MTLE did not achieve an Engel Class I (i.e. free of disabling seizures) outcome at a minimum of 2 years post-operative follow-up. We found that machine learning approaches were able to predict up to 73% of the 24 ATLR surgical patients who did not achieve a Class I outcome, at the expense of incorrect prediction for up to 31% of patients who did achieve a Class I outcome. Overall accuracies ranged from 70-80% and area under curve (AUC) of receiver operating characteristic of 0.75-0.81. We additionally found that information regarding overall extent of both total and significantly hypometabolic tissue resected was crucial to predictive performance, with AUC dropping to 0.59-0.62 using presurgical information alone. Incorporating the laterality of seizure onset and the choice of machine learning algorithm did not significantly change predictive performance.
Collectively, these results indicate that ‘acceptable’ to ‘good’ patient specific prognostication for drug resistant MTLE surgery is feasible with machine learning approaches utilizing commonly collected imaging modalities, but that information on the surgical resection region is critical for optimal prognostication.