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In vivo measurement of gadolinium diffusivity by dynamic contrast‐enhanced MRI: A preclinical study of human xenografts
Author(s) -
Koh T. S.,
Hartono S.,
Thng C. H.,
Lim T. K. H.,
Martarello L.,
Ng Q. S.
Publication year - 2013
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.24246
Subject(s) - thermal diffusivity , gadolinium , in vivo , tracer , contrast (vision) , chemistry , dynamic contrast enhanced mri , dynamic contrast , nuclear magnetic resonance , biomedical engineering , diffusion , magnetic resonance imaging , nuclear medicine , materials science , medicine , biology , radiology , physics , thermodynamics , optics , microbiology and biotechnology , organic chemistry , nuclear physics
Compartmental tracer kinetic models currently used for analysis of dynamic contrast‐enhanced MRI data yield poor fittings or parameter values that are unphysiological in necrotic regions of the tumor, as these models only describe microcirculation in perfused tissue. In this study, we explore the use of Fick's law of diffusion as an alternative method for analysis of dynamic contrast‐enhanced MRI data in the necrotic regions. Xenografts of various human cancer cell lines were implanted in 14 mice that were subjected to dynamic contrast‐enhanced MRI performed using a spoiled gradient recalled sequence. Tracer concentration was estimated using the variable flip angle technique. Poorly perfused and necrotic tumor regions exhibiting delayed and slow enhancement were identified using a k ‐means clustering algorithm. Tracer behavior in necrotic regions was shown to be consistent with Fick's diffusion equation and the in vivo gadolinium diffusivity was estimated to be 2.08 (±0.88) × 10 −4 mm 2 /s. This study proposes the use of gadolinium diffusivity as an alternative parameter for quantifying tracer transport within necrotic tumor regions. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.