Recording EEG in a High Field MRI Environment.
Abstract number :
2.081
Submission category :
Year :
2001
Submission ID :
3006
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
J.M. Zempel, MD, PhD, Pediatric Neurology and Biomedical MR Lab, Washington University, St Louis, MO; J.R. Ives, BSc, Neurology, Beth-Israel, Boston, MA; J.J. Neil, MD, PhD, Pediatric Neurology and Biomedical MR Lab, Washington University, St Louis, MO
RATIONALE: Noninvasive MRI imaging provides information about the state of the epileptic brain. The ability to record seizures and provide direct correlation with MR imaging characteristics in animal models will allow the development of applicable MR imaging sequences for use in humans. EEG recording with fiberoptic links has been adapted from human use to 4.7 T small animal MR machines (Ives, et al 2001- this meeting). Such EEG recording utilizes magnet-compatible copper wires attached to the skull for mechanical stability with silver-laced conductive epoxy. In addition the physiological state of the animal can be monitored with a fiber optic linked temperature control system, fiber optic EKG, fiber optic respiratory motion detector, and fiber optic pulse oximetry. Such monitoring provides a stable and known physiological state to explore the effect of seizures on MR imaging parameters.
METHODS: 200-250 gm male rats were anesthetized with chloral hydrate and maintained on isoflurane. Insulated copper wires were attached to the skull with conductive epoxy and cyanoacrylate. This combination provides mechanical and electrical stability when moving the animal into a small diameter MR coil. Imaging was performed on a 4.7 T Oxford/Varian MRI with 3 or 5 cm birdcage headcoils
RESULTS: Multimodality animal monitoring compatible with the MR environment was possible. Animal monitoring did not interfere with image quality for standard pulse sequences. Minimal image artifact resulted from the copper wire and conductive epoxy configuration. Both baseline and paroxysmal activity were clearly ascertained in the EEG recordings through standard gradient echo and spin echo sequences. Combined EEG and EKG recordings did not reveal significant artifact from the ballistocardiogram
CONCLUSIONS: The ability to monitor physiological parameters in an MR environment with well defined animal models will allow the development and refinement of imaging modalities for human use.
Support: Supported by NIH-NINDS NSADA NS0169 to J.Z.