Measurement of amygdala T2 relaxation time in temporal lobe epilepsy.
OBJECTIVE
To implement and validate the use of coronal dual echo T2 maps for the measurement of T2 relaxation time of the amygdala (AT2) as a rapid and reproducible method for identifying amygdala abnormality.


METHODS
20 healthy subjects and 25 patients with known hippocampal sclerosis (HS) were studied using a dual echo CSE sequence on a 1.5T MRI GE scanner. The T2 relaxation time of the amygdala was calculated and measured using a previously validated method.


RESULTS
The mean control AT2 was 88.1 ms (SD 2 ms). The coefficient of reliability was good at 6.3% test-retest and 7.4% inter-rater. The upper limit of normal AT2 was 92 ms. AT2 was abnormal ipsilaterally in six, and bilaterally in three, of 20 patients with unilateral HS. Two of five patients with bilateral HS had unilateral abnormal AT2.


CONCLUSIONS
Reliable T2 measurements can be obtained in the amygdala, and may be useful in the detection of amygdala abnormality.
Bartlett
P A
PA
MRI Unit, National Society for Epilepsy, Chalfont St Peter, Buckinghamshire, UK.
Richardson
M P
MP
Duncan
J S
JS
D000679:Amygdala / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D004292:Dominance, Cerebral / Q000502:physiology; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008432:Mathematical Computing; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results