Abstracts

Rationale: Temporal lobe epilepsy is the most common cause of persistent, medically-intractable seizures. It is also a cause of progressive memory injury. The gold standard of definitive treatment is surgery, and the use of surgical intervention requires positive imaging findings based on structural MRI (e.g. volumetry, flair signal), however, with traditional methods, significant tissue damage must occur before detection is possible. Because 73% of patients receiving surgery early are seizure free one year after surgery, the development of a novel imaging biomarker sensitive to MTS that will allow for earlier use of surgical or medical interventions could reduce morbidity significantly. The pathological substrate in the majority of temporal lobe epilepsy cases is sclerosis of the hippocampus (Hc), commonly referred to as mesial temporal sclerosis (MTS). MTS is characterized by both memory deficits and the degradation of lateral Hc tissue accompanied by considerable scarring of the tissue over time. Methods: Magnetic resonance elastography (MRE) is an emerging non-invasive tool for measuring microstructural elements of tissue that provides quantitative measures of tissue stiffness. Because sclerotic tissue should be stiffer than normal tissue, MRE may prove an important tool for early MTS detection. In this study, MTS patients and matched controls received an MRE scan and a battery of relational memory tasks. Results: Patients with significantly impaired on relational memory measures. Furthermore, MRE revealed lateralized hippocampal stiffness increases in the sclerotic hemisphere. The non-sclerotic side was found to be softer then age matched controls.  The ratio of left to right tissue stiffness dissociated patients from controls with high accuracy Finally, the significant relationship between relational memory performance and tissue stiffness was similar in both hemispheres for controls, but present only in the non-sclerotic hemisphere for patients.  Conclusions: This data is supportive for the role of this emerging technology.  Funding: Carle Foundation Hospital Research Grant