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Introduction
Approximately 20% of children with epilepsy are refractory to medical therapy, which has a significant adverse effect on patients and their families.1 The term ‘drug-resistant epilepsy’ has been proposed by the International League against Epilepsy (ILAE) to replace terms such as refractory and intractable epilepsy. Neuroimaging plays an important role in identifying epileptogenic foci that can be surgically resected. Advances in neuroimaging, including advances in scanner hardware and software, have allowed improved signal-to-noise ratio and achieve faster scan times and fewer motion artifacts. In addition, use of advanced imaging techniques, including multimodality fusion, has enabled improved lesion detection and localisation. It is important to choose tests based on their potential to further define the epileptogenic region, acknowledge their known strengths and limitations, and weigh the expected clinical benefit and incremental cost-effectiveness. Any additional test should be chosen on the basis of the likelihood that it can change the resection plan or surgical method. It should be pointed out that a review in 2011 by an ILAE panel found no studies that qualified as class 1 evidence, and little class 2 evidence on the utility of diagnostic tests in pre-surgical evaluation of patients with pediatric epilepsy.2 Recommendations provided in the present review are based on the first author’s personal experience of working in paediatric epilepsy groups over the last decade and is similar to consensus recommendations from various ILAE panels.3
Phases in the evaluation of children with epilepsy
Phase 1
One must first define the seizure syndrome and ensure that medical therapy is optimised; this includes a detailed history, including pre- and postnatal events, seizure history including the semiology (type of seizure), characteristics of onset and manifestations of the seizures, a full neurological examination, detailed electrophysiology via several electroencephalography (EEG) exams that record interictal and ictal events, and neuroimaging.
Functional imaging with single-photon emission computed tomography (SPECT) and/or positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and magneto encephalography (MEG) are also used in some cases. Results are discussed at multidisciplinary team meetings involving specialists in neurology, neurosurgery, neurophysiology, neuroradiology and neuropsychology. If the anatomical and functional images are concordant with the seizure semiology and information gathered is considered adequate, surgical resection may be planned. If there is no concordance of...