Assessment of T1 and T2* effects in vivo and ex vivo using iron oxide nanoparticles in steady state: dependence on blood volume and water exchange
2002 (English)In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 47, no 3, 461-471 p.Article in journal (Refereed) Published
Accurate knowledge of the relationship between contrast agent concentration and tissue relaxation is a critical requirement for quantitative assessment of tissue perfusion using contrast-enhanced MRI. In the present study, using a pig model, the relationship between steady-state blood concentration levels of an iron oxide nanoparticle with a hydrated diameter of 12 nm (NC100150 Injection) and changes in the transverse and longitudinal relaxation rates (1/T2* and 1/T1, respectively) in blood, muscle, and renal cortex was investigated at 1.5 T. Ex vivo measurements of 1/T2* and 1/T1 were additionally performed in whole pig blood spiked with different concentrations of the iron oxide nanoparticle. In renal cortex and muscle, 1/T2* increased linearly with contrast agent concentration with slopes of 101 +/-22 s(-1)mM(-1) and 6.5 +/-0.9 s(-1)mM(-1) (mean +/- SD), respectively. In blood, 1/T2* increased as a quadratic function of contrast agent concentration, with different quadratic terms in the ex vivo vs. the in vivo experiments. In vivo, 1/T1 in blood increased linearly with contrast agent concentration, with a slope (T1-relaxivity) of 13.9 +/- 0.9 s(-1)mM(-1). The achievable increase in 1/T1 in renal cortex and muscle was limited by the rate of water exchange between the intra- and extravascular compartments and the 1/T1-curves were well described by a two-compartment water exchange limited relaxation model.
Place, publisher, year, edition, pages
2002. Vol. 47, no 3, 461-471 p.
Animals, Blood Volume, Body Water/metabolism, Contrast Media/*pharmacokinetics, Image Processing; Computer-Assisted, Iron/*pharmacokinetics, Kidney Cortex/*anatomy & histology, Magnetic Resonance Imaging/*methods, Muscles/*anatomy & histology, Nanotechnology, Oxides/*pharmacokinetics, Particle Size, Research Support; Non-U.S. Gov't, Swine
Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:uu:diva-73117DOI: 10.1002/mrm.10066PubMedID: 11870832OAI: oai:DiVA.org:uu-73117DiVA: diva2:101028