title: Subtraction ictal SPECT coregistered to MRI for seizure focus localization in partial epilepsy.
abstract: Peri-ictal single-photon emission computed tomography (SPECT) of the brain is increasingly used in localizing the seizure focus in presurgical evaluation of patients with partial epilepsy. However, traditional side-by-side visual interpretation of ictal and interictal SPECT films is hampered by differences in slice location and tracer activity. Precise correlation of the seizure focus with a high-quality image of the underlying brain anatomy can improve the physician's understanding of seizure neurophysiology and assist in surgical planning. Computer-based methods have been developed for aligning, normalizing, and subtracting digital ictal and interictal SPECT images of the patient's brain to produce a map of the blood flow changes occurring between the seizure and resting states. These maps are then aligned with a high-resolution magnetic resonance image (MRI) of the patient's brain anatomy and fused to identify anatomical regions involved in the seizure. The purpose of this article is to review the technical components and clinical implementation of subtraction ictal SPECT, as well as to discuss recent technological advances that could extend and improve the diagnostic and localizing capacity of this method.
authors.affiliation: Section of Nuclear Medicine, Mayo Clinic, Rochester, Minn 55905, USA.
authors.forename: B H
authors.initials: BH
authors.lastname: Brinkmann
authors.forename: T J
authors.initials: TJ
authors.lastname: O'Brien
authors.forename: B P
authors.initials: BP
authors.lastname: Mullan
authors.forename: M K
authors.initials: MK
authors.lastname: O'Connor
authors.forename: R A
authors.initials: RA
authors.lastname: Robb
authors.forename: E L
authors.initials: EL
authors.lastname: So
mesh_terms: D000208:Acute Disease; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D003545:Cysteine / Q000031:analogs & derivatives; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013382:Subtraction Technique; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime; C059659:technetium Tc 99m bicisate; D003545:Cysteine