Impact of transvascular and cellular-interstitial water exchange on dynamic contrast-enhanced magnetic resonance imaging estimates of blood to tissue transfer constant and blood plasma volume.

To examine the effect of transvascular (k(be)) and cellular-interstitial water protons exchange (k(ie)) in estimates of the blood-to-tissue contrast agent transfer rate constant (K(trans)), interstitial volume fraction (v(e)), and blood plasma volume fraction (v(p)) using a full three-site two exchange (3S2X) model. Using the Bloch-McConnell equations, magnetic resonance imaging (MRI) signal arising from a 3S2X system was derived for the T(1)-weighted spoiled gradient-recalled echo (SPGR) pulse sequence. To model the effects of k(be) and k(ie) on estimates of R(1), the MRI-measured arterial input function, the different sets of values of kinetic parameters: K(trans), v(e), and v(p) and water protons exchange rates, k(be) and k(ie), were used. To calculate the tissue water protons R(1), the signal evolving from a 3S2X model was set to a monoexponential function. By comparing the estimated K(trans), v(e), and v(p) with their simulated model truth values, the impact of k(be) and k(ie) on K(trans), v(e), and v(p) was evaluated. v(p) was strongly underestimated and K(trans) and v(e) were much less influenced by k(be), when k(ie) was held constant. When k(be) was held constant, the k(ie) had a significant effect on K(trans) and v(e) and less effect on v(p). The full 3S2X model allows accurate estimation of K(trans), v(e), and v(p) and rates of water proton exchange. Copyright © 2012 Wiley Periodicals, Inc.

Citation

Ramesh Paudyal, Harish Poptani, Kejia Cai, Rong Zhou, Jerry D Glickson. Impact of transvascular and cellular-interstitial water exchange on dynamic contrast-enhanced magnetic resonance imaging estimates of blood to tissue transfer constant and blood plasma volume. Journal of magnetic resonance imaging : JMRI. 2013 Feb;37(2):435-44

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PMID: 23197427

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