DIFFUSION TENSOR IMAGING (DTI) IN PATIENTS WITH PARTIAL EPILEPSY DUE TO KNOWN OR PRESUMED MALFORMATIONS OF CORTICAL DEVELOPMENT (MCD) - PRELIMINARY RESULTS OF AN ONGOING STUDY
Abstract number :
2.227
Submission category :
Year :
2003
Submission ID :
4054
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Eva K. Ritzl, Jin-suh Kim, Afra Ritzl, Susumu Mori, Godfrey D. Pearlson, Gregory K. Bergey Epilepsy Center, Johns Hopkins University, School of Medicine, Baltimore, MD; Olin Neuropsychiatry Research Center, Hartford, CT; Institute for Medicine (IME), Cogn
Malformations of cortical development (MCD) are an important cause of partial epilepsy, however, they may be difficult to detect even on high resolution MRI. Since epilepsy surgery on patients without any visible pathology on MRI is known to be associated with a relatively poor outcome, it is important to improve our tools for the visualization of MCD and associated structures.
Diffusion tensor imaging (DTI) is a relatively new technique which specifically provides data about white matter architecture potentially affected by abnormal cortical development.
We conducted this study to evaluate the potential of DTI to demonstrate white matter changes associated with MCD.
We evaluated three patients with intractable partial epilepsy. Based on the patients[apos] seizure semiology all had frontal lobe onset seizures. Two patients had a normal conventional brain MRI and one patient had a known right frontal cortical dysplasia.
DTI images were obtained on a 1.5 T Philips Gyroscan ACS NT using single-shot echo planar imaging (EPI) with SENSE (p = 2) acquisition modified by adding diffusion weighting gradients. The imaging parameter included: TR=6543, TE=80, acquisition matrix 96x96, reconstruction matrix 256x256, FOV 240, 3 acquisitions.
Fractional anisotropy (FA) maps were calculated from the diffusion-weighted images using software developed in-house. We correlated the results with the clinical findings, the seizure onset location based on EEG recordings (with scalp and / or intractranial electrodes) and the other available imaging data.
The most dramatic changes in fractional anisotropy (FA) were seen in the patient with the known cortical dysplasia. This suggests that DTI can identify white matter changes associated with cortical dysplasias beyond those visible on conventional MRI. The areas of FA change correlated with the patient[apos]s seizure focus indicating that they may represent areas of abnormal connectivity.
DTI is a promising, non-invasive technique for the localization of white matter abnormalities associated with malformations of cortical development that give rise to partial epilepsy.
[Supported by: The National EpiFellows Foundation (research grant to EKR)]