Interictal single-photon emission computed tomography in partial epilepsy. Accuracy in localization and prediction of outcome.

The role of interictal brain single-photon emission computed tomography (SPECT) was examined using (99mTc)- labeled hexamethylpropyleneamine oxime (HMPAO) in refractory partial epilepsy. The accuracy with which SPECT localized an epileptic focus and whether it predicted long-term postoperative seizure relief were assessed. Twenty patients were evaluated, 14 of whom ultimately had anterior temporal lobectomy with follow-up ranging from 41 to 56 months. A single-headed gamma camera was used. The interictal SPECT showed ipsilateral temporal hypoperfusion in 8 (47%) of 17 patients with temporal lobe epilepsy and showed either multilobar hypoperfusion or no perfusion defects in the rest. The sensitivity and specificity were similar in patients with a more complex clinical picture who required intracranial electrodes and those who did not. Presence or absence of temporal lobe hypoperfusion did not correlate with postoperative seizure relief. It is concluded that interictal SPECT with 99mTc-HMPAO with a single-headed gamma camera does not add useful information in preoperative localization or predicting postoperative seizure relief.