title: Z-Spectrum analysis provides proton environment data (ZAPPED): a new two-pool technique for human gray and white matter.
abstract: A new technique - Z-spectrum Analysis Provides Proton Environment Data (ZAPPED) - was used to map cross-relaxing free and restricted protons in nine healthy subjects plus two brain tumor patients at 3T. First, MT data were acquired over a wide symmetric range of frequency offsets, and then a trio of quantitative biomarkers, i.e., the apparent spin-spin relaxation times (T2,f, T2,r) in both free and restricted proton pools as well as the restricted pool fraction Fr, were mapped by fitting the measured Z-spectra to a simple two-Lorentzian compartment model on a voxel-by-voxel basis. The mean restricted exchangeable proton fraction, Fr, was found to be 0.17 in gray matter (GM) and 0.28 in white matter (WM) in healthy subjects. Corresponding mean values for apparent spin-spin relaxation times were 785 µs (T2,f) and 17.7 µs (T2,r) in GM, 672 µs (T2,f) and 23.4 µs (T2,r) in WM. The percentages of Ff and Fr in GM are similar for all ages, whereas Fr shows a tendency to decrease with age in WM among healthy subjects. The patient ZAPPED images show higher contrast between tumor and normal tissues than traditional T2-weighted and T1-weighted images. The ZAPPED method provides a simple phenomenological approach to estimating fractions and apparent T2 values of free and restricted MT-active protons, and it may offer clinical useful information.
authors.affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.
authors.forename: Mitsue
authors.initials: M
authors.lastname: Miyazaki
authors.affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.
authors.forename: Cheng
authors.initials: C
authors.lastname: Ouyang
authors.affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.
authors.forename: Xiangzhi
authors.initials: X
authors.lastname: Zhou
authors.affiliation: MR Research, Toshiba Medical Research Institute, Vernon Hills, Illinois, United States of America.
authors.forename: James B
authors.initials: JB
authors.lastname: Murdoch
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Fushimi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Arakawa
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D066128:Gray Matter / Q000166:cytology* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D066127:White Matter / Q000166:cytology* / Q000473:pathology*
chemical_list: D011522:Protons