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Intravascular susceptibility agent effects on tissue transverse relaxation rates in vivo
Author(s) -
Johnson Kevin M.,
Tao Jing Zang,
Kennan Richard P.,
Gore John C.
Publication year - 2000
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/1522-2594(200012)44:6<909::aid-mrm12>3.0.co;2-u
Subject(s) - in vivo , chemistry , dysprosium , skeletal muscle , relaxation (psychology) , soft tissue , blood volume , kidney , muscle tissue , nuclear magnetic resonance , pathology , anatomy , medicine , biology , inorganic chemistry , physics , microbiology and biotechnology
Since vascular architecture differs among tissues, it was hypothesized that the change in transverse relaxation rate produced by a given tissue concentration of susceptibility contrast agent also varies by tissue. This is relevant to strategies to map regional blood volume by MRI using indicator dilution techniques. R * 2 was measured in rat organs over a range of susceptibility agent concentrations at 1.5 T. Rat red blood cells loaded with dysprosium‐DTPA‐BMA served as an intravascular susceptibility agent. Tissue samples were frozen in vivo and dysprosium concentrations were independently measured using inductively coupled plasma atomic emission spectroscopy. The slope ( k ) of R * 2 vs. tissue dysprosium concentration in sec −1 mM −1 for myocardium was 97.1 (95% C.I. 77.0–117.2), liver 122.6 (108.3–136.9), spleen 22.5 (8.8–36.3), kidney 68.1 (58.6–77.6), and skeletal muscle 77.9 (4.1–151.6); k was significantly different ( P < 0.05) for all pairings except those with skeletal muscle. Therefore, relative values of tissue blood volume derived from dynamic images of first pass contrast effects may be in error because k is not constant for different conditions. Magn Reson Med 44:909–914, 2000. © 2000 Wiley‐Liss, Inc.