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Dynamic in vivo oxymetry using overhauser enhanced MR imaging
Author(s) -
Golman Klaes,
Petersson J. Stefan,
ArdenkjærLarsen JanHenrik,
Leunbach Ib,
Wistrand LarsGöran,
Ehnholm Gösta,
Liu Kecheng
Publication year - 2000
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/1522-2586(200012)12:6<929::aid-jmri17>3.0.co;2-j
Subject(s) - imaging phantom , nuclear magnetic resonance , in vivo , nuclear overhauser effect , scanner , dipole , electron paramagnetic resonance , oxygen , proton , electron , materials science , signal (programming language) , magnetic resonance imaging , chemistry , physics , optics , nuclear magnetic resonance spectroscopy , computer science , medicine , microbiology and biotechnology , organic chemistry , radiology , quantum mechanics , biology , programming language
A noninvasive method for in vivo measurement of the oxygen concentration has been developed. By introducing a novel contrast medium (CM) based on a single electron substance, it is possible to enhance the proton signal through the Overhauser effect. A low‐field magnetic resonance scanner is used to image the proton nuclei of the object. The electron spin transition of the CM is saturated using rf irradiation. As a consequence, the nuclear polarization becomes enhanced through dipole‐dipole interaction. The signal enhancement is a function of rf power and of the EPR line width of the substance, which is influenced by the oxygen concentration. The maximum in vivo enhancement has been measured to 60. Image data, generated with different scanning parameters, is used in a postprocessing method to generate images showing pO 2 and the contrast medium concentration, respectively. The mathematical foundation of the postprocessing algorithm is outlined. The results from phantom experiments and animal experiments, in which the oxygen content of the inspired gas was varied, are presented. The potential for human imaging is discussed. J. Magn. Reson. Imaging 2000;12:929–938. © 2000 Wiley‐Liss, Inc.