Preoperative CT diagnosis of mesial temporal sclerosis for surgical treatment of epilepsy.

A computerized tomographic (CT) scanning technique has been devised by which the anatomy of the mesial temporal lobe can be examined in epileptics who are being considered for temporal lobectomy. Among 25 patients examined with this technique, 17 have had the anatomy of their mesial temporal lobe verified at craniotomy, showing close correlation between surgical findings and the high-resolution cerebrospinal fluid-enhanced CT scans. Atrophy was present in 4 patients, whereas chronic herniation of the mesial temporal structures over the free edge of the tentorium was present in 12; in 1 patient the structures were normal. The correlation of an anatomical lesion with an electroencephalographically (EEG) defined epileptogenic focus will improve the outcome of surgery for epilepsy. This CT technique aids in identifying the epileptogenic temporal lobe for patients in whom the focus is ambiguous by EEG criteria alone.