Ictal-Interictal SPECT Analysis by SPM

ISAS (Ictal-Interictal SPECT Analysis by SPM) is an objective tool for analyzing ictal vs. interictal SPECT scans. The goal of ictal SPECT is to localize the region of seizure onset for epilepsy surgery planning. ISAS was introduced and validated in two recent studies (Chang et al., 2002; McNally et al., 2005). This site is a technical supplement to (McNally et al., 2005), which should enable ISAS to be implemented at any center for further study and analysis. ISAS (Ictal-Interictal SPECT Analysis by SPM) is an objective tool for analyzing ictal vs. interictal SPECT scans. The goal of ictal SPECT is to localize the region of seizure onset for epilepsy surgery planning. ISAS was introduced and validated in two recent studies (Chang et al., 2002; McNally et al., 2005). This site is a technical supplement to (McNally et al., 2005), which should enable ISAS to be implemented at any center for further study and analysis. The basic idea of ISAS is to compute the difference between an ictal and interictal SPECT scan for a single patient. The differences of the ictal/inter-ictal comparison are checked against a healthy normal database to determine the normal expected variation. Significant increases and decreases in CBF (cerebral blood flow) between the interictal and ictal SPECT can then be detected. The analysis is conducted using SPM (statistical parametric mapping).