Hai Li, Abstract Co-Author: Nothing to Disclose

Zhong Xue PhD, Presenter: Nothing to Disclose

Mario F. Dulay, Abstract Co-Author: Nothing to Disclose

Amit Verma, Abstract Co-Author: Nothing to Disclose

Robert G. Grossman, Abstract Co-Author: Nothing to Disclose

Stephen T. C. Wong PhD, Abstract Co-Author: Nothing to Disclose

While EEG is the gold standard for identifying the location of seizure foci during the surgical work-up of patients with intractable temporal lobe epilepsy (TLE), other methods are routinely used to improve diagnostic certainty. Diffusion tensor imaging (DTI) can be used to detect the integrity of neural fibers and may be useful when conventional neuroimaging is not helpful in corroborating the side of seizure focus. This study relates white matter (WM) tract integrity in TLE with side of seizure focus using a newly developed automatic method that extracts the WM skeleton and improves the estimation of Fractional Anisotropy (FA) values.

DTI were analyzed from 12 normal controls and 18 patients diagnosed with video-EEG confirmed TLE (9 left, 9 right with conventional MRI reported as normal). The images were normalized onto the JHU-DTI-MNI atlas using a deformable registration algorithm, and the tract-based spatial statistics (TBSS) algorithm was employed to quantify the FA among 102 WM regions defined by the atlas. FA and FA asymmetry (the relative difference of FA between the corresponding left-right WM sub-region pairs) were computed. ANOVA was performed to identify the regions that significantly differed between controls and left or right TLE patients.

FA values were significantly lower between TLE patients and normal controls in many areas including the cingulum, superior temporal, and lateral orbital-frontal WM regions for left-TLE and cingulum, uncinate fasciculus, and superior temporal WM regions for right-TLE (all p values < 0.05). There were also significantly lower FA values corresponding to side of seizure foci between left and right TLE groups for inferior-frontal, superior temporal, middle temporal, and inferior temporal WM regions (p’s < 0.05). The FA asymmetry inside these regions is also significantly different among controls, left and right TLE.

Using our method, we showed that FA can be used to differentiate left from right TLE patients allowing for increased diagnostic accuracy of seizure lateralization during the pre-surgical evaluation of individuals with TLE.

To delineate TLE with side of seizure focus aiming at enhancing existing automatic DTI quantification method of seizure lateralization and pre-surgical evaluation.

Li, H, Xue, Z, Dulay, M, Verma, A, Grossman, R, Wong, S, Fractional Anisotropy Asymmetry Analysis Reveals Regions to Distinguish Left from Right Temporal Lobe Epilepsy Patients Using Diffusion Tensor Imaging.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9011115.html