Ali Tabesh PhD, Presenter: Nothing to Disclose

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

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

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

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

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

Medial temporal lobe epilepsy (MTLE) is the most common form of treatment-refractory epilepsy, affecting approximately one million Americans. Despite its prevalence, there is a lack of reliable biomarkers for monitoring the clinical course and treatment response of MTLE. Diffusion MRI (dMRI) offers a unique and powerful method to characterize structural abnormalities in MTLE and as such may provide an accurate marker to better inform treatment decisions. This study aims to investigate MTLE-related microstructural deficits with diffusional kurtosis imaging (DKI), an extension of the commonly used dMRI technique of diffusion tensor imaging (DTI) that provides complementary information to DTI.

Ten patients with left MTLE and 20 age- and sex-matched control subjects underwent DKI and T1-weighted (T1w) scans on a 3T clinical MRI system. The MTLE diagnosis was based on a history of partial epilepsy and the presence of unilateral hippocampal sclerosis on conventional diagnostic MRI or unilateral seizure onset confirmed by ictal video-electroencephalography. DTI and diffusional kurtosis parametric maps were obtained from the DKI scans, and were then submitted to voxel-wise analysis yielding maps of microstructural deficits. T1w scans were submitted to voxel-based morphometry yielding maps of tissue volume (TV) loss.

The mean kurtosis (MK) showed extensive microstructural abnormalities in patients, including significant reductions in bilateral hippocampi, perihippocampal WM, pericingulate regions, frontal lobes, orbitofrontal regions, and occipitoparietal areas. The MD in patients was significantly increased in the ipsilateral perihippocampal area and bilateral orbitofrontal regions. The FA showed significant reductions in bilateral perihippocampal WM and the ipsilateral thalamus. The TV was significantly reduced in the ipsilateral hippocampus, contralateral insula, bilateral thalami, cerebellum, and occipital cortex. 

This preliminary study suggests that DKI may provide substantially more sensitive markers of structural abnormalities in MTLE than DTI and TV measures. The extent of abnormalities observed with MK is consistent with DTI and TV studies with significantly larger cohorts. Supported by NSF/EPSCoR under Grant No. EPS-0919440.

DKI may provide a highly sensitive marker of microstructural abnormalities in MTLE and as such may better inform treatment decisions.

Tabesh, A, Jensen, J, Helpern, J, Spampinato, M, Edwards, J, Bonilha, L, Diffusional Kurtosis Imaging Reveals Widespread Structural Abnormalities in Medial Temporal Lobe Epilepsy.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12033670.html