Recent advances in imaging epilepsy

Value of clinical features to differentiate refractory epilepsy from mimics: a prospective longitudinal cohort study

BACKGROUND AND PURPOSE

Misdiagnosis of refractory epilepsy (rE) is common and such patients experience a long diagnostic delay. Our aim was to identify key clinical/laboratory factors in order to obtain an alternative diagnosis in patients referred for rE.

METHODS

Between January 2010 and December 2015, 125 consecutive patients with a diagnosis of rE were prospectively enrolled. All patients underwent a comprehensive neurological, neuropsychiatric and cardiological evaluation, and had an observation time of at least 1 year after the study entry.

RESULTS

Diagnosis of rE was confirmed in 104/125 (83.2%) patients (55 women, mean age 38.8 ± 14.3 years). Thirteen/125 patients (10.4%, seven women, mean age 50.8 ± 20.9) were diagnosed with syncope, which was cardiac/cardio inhibitory in 9/13 (69%). The remaining 8/125 patients (6.4%, six women, mean age 41.2 ± 14.6 years) were diagnosed with psychogenic non-epileptic seizures. Age at onset had a high accuracy in differentiating patients with syncope from others, with the best cut-off age at 35 years and above. Abnormal brain magnetic resonance imaging (MRI) had a significant yield of about 70% in rE. A diagnostic model including age at onset and brain MRI was highly accurate in differentiating patients with syncope from others. In patients with cardiac/cardio inhibitory syncope, the point score of historical features was ≥1 and falsely favoured the diagnosis of epileptic seizures.

CONCLUSIONS

This prospective cohort study identifies rE mimics who are at high risk of morbidity and mortality. rE starting in adulthood should raise a high suspicion of cardiac syncope. Brain MRI is accurate in differentiating rE from other conditions.

Ictal-interictal continuum: A proposed treatment algorithm

The ictal-interictal continuum (IIC) is characterized by periodic and/or rhythmic EEG patterns that occur with relative high frequency in critically ill patients. Several studies have reported that some patterns seen within the continuum are independently associated with poor outcome. However there is no consensus regarding when to treat them or how aggressive treatment should be. In this review we examine peer-reviewed original scientific articles, guidelines and reviews indexed in PubMed and summarize current knowledge related to the ictal-interictal continuum. A treatment algorithm to guide management of critically ill patients with EEG patterns that fall along the IIC is proposed. The algorithm-based on best current practice in adults-takes into account associated clinical events, risk factors for developing seizures, response to medication trials and biomarkers of neuronal injury.

Lesions masquerading as acute stroke

Rapid and accurate recognition of lesions masquerading as acute stroke is important. Any incorrect or delayed diagnosis of stroke mimics will not only increase the risk of being exposed to unnecessary and possibly dangerous interventional therapies, but will also delay proper treatment. In this article, written from a neuroradiologist's perspective, we classified these lesions masquerading as acute stroke into three groups: lesions that may have "normal imaging," lesions that are "symptom mimics" but on imaging clearly not a stroke, and lesions that are "symptom and imaging mimics" with imaging findings similar to stroke. We focused the review on neuroimaging findings of the latter two groups ending with a suggestion for a diagnostic approach in the form of an algorithm.

Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts

Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic changes of the microvasculature surrounding the epileptic neurons. The epilepsy mapping results were confirmed by a simultaneously recorded electroencephalogram signal during epileptic seizure. Our new epilepsy mapping tool, with high temporal and spatial resolution and dual optical contrasts, may find many applications, such as drug development and epilepsy surgery.