DIFFUSION TENSOR IMAGING IN TEMPORAL LOBE EPILEPSY
Abstract number :
1.250
Submission category :
Year :
2002
Submission ID :
1325
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Karine J. Abou Khaled, Feroze Mohamed, Ehren Carine, Selina Parveen, Scott Faro, May Yazeji, Bassam A. Assaf. Neurology, MCP Hahnemann Hospital, Philadelphia, PA; Radiology, MCP Hahnemann Hospital, Philadelphia, PA; Neurology, MCP Hahnemann Hospital, Phil
RATIONALE: Non invasive techniques are becoming increasingly important in mapping the seizure focus in patients with intractable epilepsy. Diffusion Tensor Imaging (DTI) is an innovative non-invasive tool for evaluating structural and phisiologic state in biological tissue by measuring the diffusion process of water molecules. We conducted this study to investigate the potential value of DTI in identifying and localizing the seizure focus in patients with intractable Temporal Lobe Epilepsy (TLE).
METHODS: We evaluated a total of 8 patients with intractable TLE being considered for epilepsy surgery with DTI of the brain and compared measurements of diffusivity or Trace D and fractional anisotropy (FA) from hippocampal regions bilaterally to those of normal subjects (normal control). DTI imaging was performed on a 1.5 T Vision MR scanner (Siemens Medical Systems,Erlangen,Germany) using a single shot echo planar diffusion weighted imaging sequence. The imaging parameters included : TR= 6000 ms,TE=100 ms,FOV=240 ms and 4 acquisitions. The maps of trace D and FA were calculated from diffusion-weighted images using software written in IDL ( Interactive Data language,USA). We compared the FA and Trace D indices from multiple and symmetrical voxels sampling regions from hippocampal formation in both patients and control groups. We also correlated the measurements with the clinical findings, ictal EEG onset and other neuroimaging indicators of the seizure focus of all 8 TLE patients.
RESULTS: Five patients demonstrated increased hippocampal diffusivity measurements ipsilateral to the seizure focus when compared to those sampling the contralateral hippocampus and to those of normal subjects.
Analysis of the five patients with negative brain MRI revealed increased trace (D) in Hippocampal regions of interest in 3 patients. There was no significant change in anisotropy.
CONCLUSIONS: Trace D calculated from DTI methods is a particularly useful parameter to detect structural abnormalities in vivo and is a useful indicator of the seizure focus. DTI is a promising and non-invasive imaging technique for localizing and mapping the seizure focus in TLE.