Ali Tabesh PhD, Presenter: Nothing to Disclose

Travis O. Nesland, Abstract Co-Author: Nothing to Disclose

Jens H Jensen PhD, Abstract Co-Author: Nothing to Disclose

Maria Vittoria Spampinato MD, Abstract Co-Author: Nothing to Disclose

Jonathan C. Edwards, Abstract Co-Author: Nothing to Disclose

Joseph A. Helpern PhD, Abstract Co-Author: License agreement, Siemens AG

Leonardo Bonilha MD, PhD, Abstract Co-Author: Nothing to Disclose

Although medial temporal lobe epilepsy (MTLE) is a common neurological disorder, there remains a lack of reliable biomarkers for monitoring its clinical course and treatment response. Diffusion MRI (dMRI) tractography is a unique and powerful tool for characterization of white matter (WM) connectivity and may provide entirely new insights into network abnormalities associated with MTLE. The goals of this study were to investigate WM connectivity changes in MTLE, and to evaluate the association between these alterations and disease severity (seizure frequency) in patients.

Nineteen patients with MTLE and 28 age- and sex-matched healthy control subjects underwent dMRI scans. Patients were divided into a well-controlled (≤ 4 seizures a year) and a poorly controlled subgroup based on their response to antiepileptic drug therapy. The two subgroups did not significantly differ in terms of age, age of seizure onset, or duration of disease. Streamline tractography was employed to quantify the WM connectivity of the temporal lobe ipsilateral to the seizure onset zone.

Patients showed a significantly lower degree of connectivity than controls in the connections between the following pairs of regions: isthmus of cingulate gyrus and parahippocampal cortex (PHC), fusiform gyrus and PHC, and inferior temporal cortex and PHC. Poorly-controlled patients showed a significantly higher degree of connectivity than well-controlled patients in the connections between the following regions: temporal pole and putamen, and entorhinal cortex and amygdala.

Our results suggest that WM connectivity measures derived from dMRI tractography may be sensitive to altered axonal connectivity in MTLE. Moreover, WM connectivity markers may potentially enable more reliable identification of patients with medication-refractory MTLE. Supported by the Foundation of the American Society of Neuroradiology and the South Carolina Clinical and Translational Research Institute.

Axonal connectivity measures based on dMRI tractography may provide complementary information for clinical evaluation of MTLE.

Tabesh, A, Nesland, T, Jensen, J, Spampinato, M, Edwards, J, Helpern, J, Bonilha, L, Altered Axonal Connectivity in Medial Temporal Lobe Epilepsy: Association with Disease Severity.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13023941.html