title: Mapping of oxygen by imaging lipids relaxation enhancement: a potential sensitive endogenous MRI contrast to map variations in tissue oxygenation.
abstract: OBJECTIVE
  Because of its paramagnetic properties, oxygen may act as an endogenous magnetic resonance imaging contrast agent by changing proton relaxation rates. Changes in tissue oxygen concentrations have been shown to produce changes in relaxation rate R1 of water. The aim of the study was to improve the sensitivity of oxygen enhanced R1 imaging by exploiting the higher solubility of oxygen in lipids (as compared with water) to sensitively monitor changes in tissue oxygen levels by selectively measuring the R1 of lipids.
  
  
  METHODS
  The method, with the acronym "MOBILE" (mapping of oxygen by imaging lipids relaxation enhancement), was applied in different mouse models of hypoxic processes on a 11.7 T magnetic resonance imaging system. MOBILE was compared with R*2, R1 of water, and with pO2 measurements (using electron paramagnetic resonance oximetry). MOBILE was also applied in the brain of healthy human volunteers exposed to an oxygen breathing challenge on a 3 T magnetic resonance imaging system.
  
  
  RESULTS
  MOBILE was shown to be able to monitor changes in oxygenation in tumor, peripheral, liver, and brain tissues. The clinical translation was demonstrated in human volunteers.
  
  
  CONCLUSIONS
  MOBILE arises as a promising noninvasive and sensitive tool for diagnosis and therapeutic guidance in disorders involving hypoxia.
authors.affiliation: Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Bénédicte F
authors.initials: BF
authors.lastname: Jordan
authors.forename: Julie
authors.initials: J
authors.lastname: Magat
authors.forename: Florence
authors.initials: F
authors.lastname: Colliez
authors.forename: Elif
authors.initials: E
authors.lastname: Ozel
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Fruytier
authors.forename: Valérie
authors.initials: V
authors.lastname: Marchand
authors.forename: Lionel
authors.initials: L
authors.lastname: Mignion
authors.forename: Caroline
authors.initials: C
authors.lastname: Bouzin
authors.forename: Patrice D
authors.initials: PD
authors.lastname: Cani
authors.forename: Caroline
authors.initials: C
authors.lastname: Vandeputte
authors.forename: Olivier
authors.initials: O
authors.lastname: Feron
authors.forename: Nathalie
authors.initials: N
authors.lastname: Delzenne
authors.forename: Uwe
authors.initials: U
authors.lastname: Himmelreich
authors.forename: Vincent
authors.initials: V
authors.lastname: Denolin
authors.forename: Thierry
authors.initials: T
authors.lastname: Duprez
authors.forename: Bernard
authors.initials: B
authors.lastname: Gallez
mesh_terms: D000818:Animals; D001943:Breast Neoplasms; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008055:Lipids / Q000032:analysis; D008279:Magnetic Resonance Imaging; D051379:Mice; D008991:Monitoring, Physiologic; D009369:Neoplasms / Q000378:metabolism; D010092:Oximetry; D010100:Oxygen / Q000032:analysis*; D011522:Protons; D020521:Stroke
chemical_list: D003287:Contrast Media; D008055:Lipids; D011522:Protons; D010100:Oxygen