title: Combination of event-related fMRI and diffusion tensor imaging in an infant with perinatal stroke.
abstract: Focal ischemic brain injury, or stroke, is an important cause of later handicap in children. Early assessment of structure-function relationships after such injury will provide insight into clinico-anatomic correlation and potentially guide early intervention strategies. We used combined functional MRI (fMRI) with diffusion tensor imaging (DTI) in a 3-month-old infant to explore the structure-function relationship after unilateral perinatal stroke that involved the visual pathways. With visual stimuli, fMRI showed a negative BOLD activation in the visual cortex of the intact right hemisphere, principally in the anterior part, and no activation in the injured hemisphere. The functional activation in the intact hemisphere correlated clearly with the fiber tract of the optic radiation visualized with DTI. DTI confirmed the absence of the optic radiation in the damaged left hemisphere. In addition, event-related fMRI (ER-fMRI) experiments were performed to define the characteristics of the BOLD response. The shape is that of an inverted gamma function (similar to a negative mirror image of the known positive adult BOLD response). The maximum decrease was reached at 5-7 s with signal changes of -1.7 +/- 0.4%.Thus, this report describes for the first time the combined use of DTI and event-related fMRI in an infant and provides insight into the localization of the fMRI visual response in the young infant and the characteristics of the BOLD response.
authors.affiliation: Department of Radiology, University Hospital of Geneva, 1211, Geneva, Switzerland.
authors.forename: Mohamed L
authors.initials: ML
authors.lastname: Seghier
authors.forename: François
authors.initials: F
authors.lastname: Lazeyras
authors.forename: Slava
authors.initials: S
authors.lastname: Zimine
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Maier
authors.forename: Sylviane
authors.initials: S
authors.lastname: Hanquinet
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Delavelle
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Volpe
authors.forename: Petra S
authors.initials: PS
authors.lastname: Huppi
mesh_terms: D001238:Asphyxia Neonatorum / Q000175:diagnosis* / Q000503:physiopathology; D019575:Blindness, Cortical / Q000151:congenital / Q000175:diagnosis / Q000503:physiopathology; D002544:Cerebral Infarction / Q000151:congenital* / Q000175:diagnosis / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D018917:Optic Neuropathy, Ischemic / Q000151:congenital / Q000175:diagnosis / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology*; D014794:Visual Fields / Q000502:physiology; D014795:Visual Pathways / Q000098:blood supply / Q000503:physiopathology*