title: Does hippocampal FDG-PET asymmetry predict verbal memory dysfunction after left temporal lobectomy?
abstract: The primary aim of this study was to determine whether hippocampal asymmetries in fluorodeoxyglucose (FDG) uptake on preoperative PET scans would predict post-temporal lobectomy verbal memory (VM) decline in patients with left temporal lobe epilepsy. A quantitative asymmetry index (AI) of uptake values within a hippocampal region of interest (ROI) was defined by an automated technique. No statistically significant effect of the hippocampal AI on the outcome measure, the pre- to postsurgical change in Logical Memory Percent Retention, was evident. Post hoc analyses revealed that AIs of the superior and inferior temporal gyri approached significance, however, with relatively greater left-sided preoperative metabolism predicting better VM outcomes. This finding suggests reorganization of function and/or retained function of remaining tissue. Although hippocampal FDG-PET asymmetries did not significantly predict changes in VM, the predictive value of neocortical AIs should be further explored. Automated ROI parcellation provides a feasible tool for use in such investigations.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. bleeman1@bidmc.harvard.edu
authors.forename: Beth A
authors.initials: BA
authors.lastname: Leeman
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Leveroni
authors.forename: Keith A
authors.initials: KA
authors.lastname: Johnson
mesh_terms: D000328:Adult; D001931:Brain Mapping; D015331:Cohort Studies; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D019788:Fluorodeoxyglucose F18; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000000981:diagnostic imaging*; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods; D011612:Psychosurgery / Q000009:adverse effects; D012189:Retrospective Studies; D016896:Treatment Outcome; D014706:Verbal Learning / Q000502:physiology*; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18