title: Functional brain MR imaging based on bolus tracking with a fast T2*-sensitized gradient-echo method.
abstract: Dynamic physiological scanning, based on temporary changes in local field homogeneity during the passage of a contrast agent bolus, has been performed hitherto with echo-planar imaging (EPI) or conventional gradient-recalled techniques (FLASH). Here, it is shown that the T2* sensitivity of conventional FLASH techniques can be improved drastically on a conventional whole body instrument by delaying the gradient-echo until the subsequent TR-period without increasing total imaging time. Examples are given for a full k-space matrix (128 x 256) obtained within 2 s with a TE of 25 ms, resulting in images free of artifacts. The method is applied to bolus tracking through the brain of healthy volunteers during visual stimulation and in the dark. An average increase of regional cerebral blood volume (rCBV) in the visual cortex of 10.9% (n = 9, p = .001) was found.
authors.affiliation: In Vivo NMR Research Center, National Institutes of Health, Bethesda, MD 20892.
authors.forename: C T
authors.initials: CT
authors.lastname: Moonen
authors.forename: F A
authors.initials: FA
authors.lastname: Barrios
authors.forename: J R
authors.initials: JR
authors.lastname: Zigun
authors.forename: J
authors.initials: J
authors.lastname: Gillen
authors.forename: G
authors.initials: G
authors.lastname: Liu
authors.forename: G
authors.initials: G
authors.lastname: Sobering
authors.forename: R
authors.initials: R
authors.lastname: Sexton
authors.forename: J
authors.initials: J
authors.lastname: Woo
authors.forename: J
authors.initials: J
authors.lastname: Frank
authors.forename: D R
authors.initials: DR
authors.lastname: Weinberger
mesh_terms: D001810:Blood Volume; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000008:administration & dosage*; D019786:Gadolinium DTPA; D006801:Humans; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000008:administration & dosage; D004369:Pentetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives*; D010775:Photic Stimulation
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA