Seizure imaging allows us to visualize the aftereffects of individual seizures with high anatomical precision and within a short timeframe. These changes can include localized edema, the deposition of blood-borne substances such as haem iron and contrast agents, and alterations in metabolite concentrations.
Why Is It Needed?
Up to a third of people with focal epilepsy do not achieve adequate seizure control with antiepileptic drugs. Many of these individuals are candidates for epilepsy surgery, which can significantly improve their quality of life. However, achieving the best possible outcomes, and providing accurate predictions of post-surgical success, relies on precisely mapping seizure activity.
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Unfortunately, in up to half of all cases, standard preoperative assessments fail to provide conclusive results. This underscores the need for novel imaging techniques that can offer deeper insights into seizure-related brain changes.
How Do We Image Seizures?
Seizures leave behind subtle traces in the brain—tiny shifts in blood flow, metabolic changes, and even deposits of iron from blood. Standard imaging techniques often miss these details, but advanced methods are now giving us a clearer picture:
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Quantitative Susceptibility Mapping (QSM) – Seizures can cause small amounts of blood leakage or iron accumulation due to a compromised blood brain barrier, leaving behind microscopic traces of blood-borne substances, including iron. QSM is a cutting-edge MRI technique that maps these iron deposits, helping us pinpoint areas affected by seizures.
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Chemical Exchange Saturation Transfer (CEST) – CEST imaging allows us to detect shifts in free proteins and other metabolites that occur peri-ictally, offering a window into the biochemical changes that occur after a seizure. This helps us find seizure-affected regions that might otherwise go unnoticed.
Point-of-Care Diffusion MRI – After a seizure, brain tissue temporarily swells, disrupting how water moves through tissues. With portable ultra-low-field MRI, diffusion imaging can be done just seconds after the seizure ends, even at the bedside. This allows for near-instantaneous assessment of seizure-related diffusion changes.
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Single Photon Emission Computed Tomography (SPECT) – Seizures trigger rapid surges in brain activity, and with them, changes in blood flow. SPECT helps us track these shifts, capturing a functional map of seizure onset zones, even after the seizure has ended.
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Arterial Spin Labeling (ASL) – Similar to SPECT, ASL detects blood flow changes, but it does so without the need for injected contrast agents. This makes it a safer, non-invasive way to visualize perfusion differences in seizure-affected brain regions.
Bringing It All Together: A Patient-Centered Approach
No single imaging method tells the whole story. Seizures affect the brain in multiple ways, structurally, chemically, and functionally. By combining different imaging techniques, we can build a comprehensive, multi-layered view of seizure activity, helping us detect what would otherwise be missed.
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More importantly, this isn’t just about better scans, it’s about better care. Every patient is unique and our goal is to provide individualized imaging. Whether it’s real-time bedside diffusion MRI or advanced metabolic mapping, our approach ensures that each patient receives the most accurate diagnosis and the best possible treatment plan.