CHEMICAL SHIFT IMAGING (CSI) IN PATIENTS WITH INTRACTABLE EPILEPSY
Abstract number :
2.207
Submission category :
Year :
2003
Submission ID :
3763
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Abuhuziefa Abubakr, Manzar Ashtari, Ilse Wambacq, Lawerence Tanenbaum New Jersey Neuroscience Institute, Seton Hall University, Edison, NJ; Radiology Department, Long Island Jewish Medical Center, New Hyde Park, NY; Edison Imaging Center, JFK Medical Cent
Identification of epileptogenic focus is essential for good surgical outcome in patients with intractable epilepsy. Routine MR evaluation of these patients does not consistently reveal the abnormality. Metabolic imaging on the other hand may provide valuable information that could be crucial in patient management. Due to the high amount of susceptibility in the medial temporal region single voxel spectroscopy (SVS) is technically challenging and time consuming. We have applied a more advanced method of chemical shift imaging (CSI) that provides the same information in less time with higher success rate in the acquisition of superior metabolite maps.
Frontal and medial temporal CSI were obtained in 8 TLE (mean age of 33 yrs) and frontal CSI in 3 FLE (mean age 23.3 yrs) patients and 12 healthy volunteers. All patients were scanned on a 3T GE MRI system (GE Milwaukee, WI). ROI[rsquo]s were placed in the resultant metabolite maps in the medial temporal and frontal lobe areas in both hemispheres. Metabolite ratios of NAA/Cr, NAA/Cho, as well as absolute values for NAA, Cho, and Cr were obtained.
Utilizing the frontal and medial temporal CSI images, NAA and Co metabolite maps were reconstructed for all TLE patients. Six out of eight patients showed clear low signal abnormalities in their NAA map concordant with their epileptogenic foci as compared to the contralateral side and normal control. TLE patients showed no obvious abnormities in their frontal NAA maps. Frontal NAA maps of all 3 FLE patients showed abnormalities that corresponded to the seizure focus. There was no correlation between the Co map and the seizure focus in either TLE or FLE patients. Using ROI analysis values of NAA/Cr and Co/Cr were quantified and correlated to the maps.
This study demonstrates the application of CSI and its corresponding metabolite maps in patients with intractable epilepsy. CSI showed good correlation with seizure foci of TLE and FLE patients. There was no correlation between the amount of Co and seizure foci. We were unable to find any evidence of extratemporal metabolic abnormalities in our patient group. We recommend CSI over SVS especially for imaging of the TLE patients where the abnormality is adjacent to an area that presents extreme challenge for SVS.