MRI VOLUMETRY AND T2 RELAXOMETRY OF THE AMYGDALA IN NEWLY-DIAGNOSED AND CHRONIC TEMPORAL-LOBE EPILEPSY

Little is known about the appearance and severity of amygdaloid damage in temporal lobe epilepsy, particularly in its early stages. In the p resent magnetic resonance imaging study, we measured amygdaloid volume s and T2 relaxation times in 29 patients with newly diagnosed and in 5 4 patients with chronic temporal lobe epilepsy. The control population included 25 normal subjects. In the newly diagnosed patients, the mea n amygdaloid volume did not differ from that in controls. Also, in the chronic patients the mean amygdaloid Volume did not differ from that in controls or in newly diagnosed patients. However, in 19% of the chr onic patients the amygdaloid volume was reduced by at least 20%. Moreo ver, in all of the epilepsy patients, both chronic and newly diagnosed , we found an inverse correlation between the number of epileptic seiz ures the patient had experienced and the amygdaloid volume on the foca l side (focus on the left, r = - 0.371, P < 0.01; focus on the right, r = - 0.348, P < 0.05). The mean T2 relaxation time in newly diagnosed or chronic patients did not differ from each other or from control va lues. However, the T2 relaxation time of the left amygdala was greater than or equal to 111 msec (i.e., greater than or equal to 2 S.D. over the mean T2 time of the left amygdala in control subjects) in seven ( 10%) patients, one of which was newly diagnosed and six were chronic. The T2 time of the right amygdala was prolonged in eight (12%) patient s, three of which were newly diagnosed and five were chronic. We did n ot find any clear asymmetries in amygdaloid volumes or T2 relaxation t imes between the ipsilateral and contrarateral sides relative to seizu re focus. According to the present findings, signs of amygdaloid damag e were observed in approximately 20% of patients with temporal lobe ep ilepsy, most of which had chronic epilepsy. (C) 1997 Elsevier Science B.V.