Hippocampal T(2) abnormalities correlate with antecedent events and help predict seizure intractability.
BACKGROUND
We performed hippocampal T(2) relaxometry as part of a routine magnetic resonance imaging (MRI) examination in 50 normal controls and 127 consecutive patients referred because of suspected seizures.


METHODS
On the basis of T(2) values in controls (100.2 +/- 4.2 ms) we defined normal as <110 ms (<mean + 2 SD), borderline as 110-113 ms (mean + 2 SD to mean + 3 SD) and abnormal as >113 ms (>mean + 3 SD).


RESULTS
After detailed investigation, 103 of these 127 patients had epilepsy and 24 did not. In the nonepilepsy group, none had abnormal hippocampal T(2) values. Twenty-seven of the 103 patients in the epilepsy group had abnormal values, 7 were borderline and 69 were normal. Only 5 patients with abnormal T(2) values did not have temporal lobe epilepsy: 1 had extratemporal lobe epilepsy, 1 had generalized epilepsy and 3 had unclassified epilepsy. Twenty-two of 27 (81%) patients with abnormal hippocampal T(2) values had intractable epilepsy [compared with 32 of 69 (46%) patients with normal values; p < 0.05, chi(2) test]. Two thirds of patients with abnormal values had a history of a major antecedent event (compared to only 7% of those with normal values, p < 0.05, chi(2) test).


CONCLUSIONS
Abnormal T(2) relaxometry is significantly associated with intractable epilepsy as well as with major antecedent events.
Jackson
G D
GD
Brain Imaging Research Institute, Departments of Neurology and Radiology, Boronia Centre, West Heidelberg, Austin and Repatriation Medical Centre, Howard Florey Institute and Department of Medicine University of Melbourne, Vic., Australia.
Kim
S E
SE
Fitt
G J
GJ
Mitchell
A L
AL
Syngeniotis
A
A
Berkovic
S F
SF
D000328:Adult; D017668:Age of Onset; D004827:Epilepsy / Q000175:diagnosis; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011379:Prognosis; D012640:Seizures / Q000175:diagnosis* / Q000453:epidemiology