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Simultaneous measurement of arterial input function and tumor pharmacokinetics in mice by dynamic contrast enhanced imaging: Effects of transcytolemmal water exchange
Author(s) -
Zhou Rong,
Pickup Stephen,
Yankeelov Thomas E.,
Springer Charles S.,
Glickson Jerry D.
Publication year - 2004
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/mrm.20143
Subject(s) - gadodiamide , bolus (digestion) , pharmacokinetics , chemistry , nuclear medicine , dynamic contrast enhanced mri , gadolinium , magnetic resonance imaging , nuclear magnetic resonance , medicine , radiology , physics , organic chemistry
A noninvasive technique for simultaneous measurement of the arterial input function (AIF) for gadodiamide (Omniscan) and its uptake in tumor was demonstrated in mice. Implantation of a tumor at a suitable location enabled its visualization in a cardiac short axis image. Sets of gated, low‐resolution saturation recovery images were acquired from each of five tumor‐bearing mice following intravenous administration of a bolus of contrast agent (CA). The AIF was extracted from the signal intensity changes in left ventricular blood using literature values of the CA relaxivity and a precontrast T 1 map. The time‐dependent 1 H 2 O relaxation rate constant ( R 1 = 1/ T 1 ) in the tumor was modeled using the BOLus Enhanced Relaxation Overview (BOLERO) method in two modes regarding the equilibrium transcytolemmal water exchange system: 1) constraining it exclusively to the fast exchange limit (FXL) (the conventional assumption), and 2) allowing its transient departure from FXL and access to the fast exchange regime (FXR), thus designated FXL/FXR. The FXL/FXR analysis yielded better fittings than the FXL‐constrained analysis for data from the tumor rims, whereas the results based on the two modes were indistinguishable for data from the tumor cores. For the tumor rims, the values of K trans (the rate constant for CA transfer from the vasculature to the interstitium) and v e (volume fraction of the tissue extracellular and extravascular space) returned from FXL/FXR analysis are consistently greater than those from the FXL‐constrained analysis by a factor of 1.5 or more corresponding to a CA dose of 0.05 mmole/kg. Magn Reson Med 52:248–257, 2004. © 2004 Wiley‐Liss, Inc.