Open AccessImaging of H 2 17 O distribution in the brain of a live rat by using proton-detected 17 O MRI
Author(s) -
Itamar Ronen,
Hellmut Merkle,
Kâmil Uğurbil,
Gil Navon
Publication year - 1998
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.95.22.12934
Subject(s) - chemistry , oxygen 17 , oxygen , proton , nuclear magnetic resonance , analytical chemistry (journal) , physics , chromatography , organic chemistry , quantum mechanics
Imaging of H2 17 O has a number of important applications. Mapping the distribution of H2 17 O produced by oxidative metabolism of17 O-enriched oxygen gas may lead to a new method of metabolic functional imaging; regional cerebral blood flow also can be measured by measuring the H2 17 O distribution after the injection of17 O-enriched physiological saline solution. Previous studies have proposed a method for indirect detection of17 O. The method is based on the shortening of the proton T2 in H2 17 O solutions, caused by the residual17 O-1 H scalar coupling and transferred to the bulk water via fast chemical exchange. It has been shown that the proton T2 of H2 17 O solutions can be restored to that of H2 16 O by irradiating the resonance frequency of the17 O nucleus. The indirect17 O image thus is obtained by taking the difference between two T2 -weighted spin-echo images: one acquired after irradiation of the17 O resonance and one acquired without irradiation. It also has been established that, at relatively low concentrations of H2 17 O, the indirect method yields an image that quantitatively reflects the H2 17 O distribution in the sample. The method is referred to as PRIMO (proton imaging of oxygen). In this work, we showin vivo proton images of the H2 17 O distribution in a rat brain after an i.v. injection of H2 17 O-enriched physiological saline solution. Implementing the indirect detection method in an echo-planar imaging sequence enabled obtaining H2 17 O images with good spatial and temporal resolution of few seconds.