Diffusion mapping applied to mesial temporal lobe epilepsy: preliminary observations.
OBJECTIVE
To evaluate whether diffusion mapping could lateralize intractable seizures in mesial temporal lobe epilepsy (MTLE) patients.


BACKGROUND
Animal seizure models show acute postictal depression of the apparent diffusion coefficient of water (ADCw), interictal normalization, then chronic elevation.


METHODS
The hippocampal plane was imaged with five diffusion weightings along each axis. Three orthogonal ADCw maps were averaged to produce an isotropic ADCw map.


RESULTS
In all eight MTLE patients, ADCw was elevated by a mean of 10+/-3% (p<0.01, paired t-test) interictally in the ipsilateral hippocampus, where side of seizure focus was determined electrographically with corroboration by volumetric MRI studies. Measured ADCw values in phantoms and five normal brains agree with published values.


CONCLUSIONS
Brain tissue with interictally increased ADCw may represent an epileptogenic region with neuronal loss, gliosis, and expanded extracellular space (hippocampal sclerosis). Thus, diffusion mapping may confirm seizure lateralization.
UAB Epilepsy Center and Center for Nuclear Imaging Research, Department of Neurology, University of Alabama at Birmingham, 35294-0021, USA.
J W
JW
Hugg
E J
EJ
Butterworth
R I
RI
Kuzniecky
D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D004058:Diffusion; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D005911:Gliosis; D006624:Hippocampus / Q000473:pathology / Q000502:physiology / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000473:pathology / Q000502:physiology; D012016:Reference Values; D012640:Seizures / Q000503:physiopathology