High reproducibility of regional abnormalities on interictal 123I-IMP SPECT brain scans in adults with partial epilepsy.

The reproducibility of two N-isopropyl-(iodine 123) p-iodoamphetamine (123I-IMP single photon emission computed tomography (SPECT) scans both taken during interictal periods was studied in 13 adult patients with partial epilepsy who had normal CT scans. The frequency of the seizures and the nature of the ictal symptoms were virtually unchanged during the interval between the two SPECT scans performed in each case. In 8 (72.7%) of 11 patients who had abnormal images consisting of focal hypofixation images of 123I-IMP, i.e. zones of decreased regional cerebral blood flow on the first scans, complete or partial regional reproduction of the SPECT abnormalities was observed. This high reproducibility supports the usefulness of SPECT scans in the regional diagnosis of epileptic foci.