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Assessment of tumor response to oxygen challenge using quantitative diffusion MRI in an animal model
Author(s) -
Zhang Zhongwei,
Yuan Qing,
Zhou Heling,
Zhao Dawen,
Li Li,
Gerberich Jenifer L.,
Mason Ralph P.
Publication year - 2015
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25071
Subject(s) - intravoxel incoherent motion , nuclear medicine , oxygen , hyperoxia , magnetic resonance imaging , diffusion mri , nuclear magnetic resonance , voxel , breathing , diffusion , perfusion , medicine , chemistry , materials science , physics , radiology , anatomy , organic chemistry , thermodynamics
Purpose To assess tumor response to oxygen challenge using quantitative diffusion magnetic resonance imaging (MRI). Materials and Methods A well‐characterized Dunning R3327‐AT1 rat prostate cancer line was implanted subcutaneously in the right thigh of male Copenhagen rats ( n = 8). Diffusion‐weighted images (DWI) with multiple b values (0, 25, 50, 100, 150, 200, 300, 500, 1000, 1500 s/mm 2 ) in three orthogonal directions were obtained using a multishot FSE‐based Stejskal‐Tanner DWI sequence (FSE‐DWI) at 4.7T, while rats breathed medical air (21% oxygen) and with 100% oxygen challenge. Stretched‐exponential and intravoxel incoherent motion (IVIM) models were used to calculate and compare quantitative diffusion parameters: diffusion heterogeneity index (α), intravoxel distribution of diffusion coefficients (DDC), tissue diffusivity (Dt), pseudo‐diffusivity (Dp), and perfusion fraction (f) on a voxel‐by‐voxel basis. Results A significant increase of α (73.9 ± 4.7% in air vs. 78.1 ± 4.5% in oxygen, P = 0.0198) and a significant decrease of f (13.4 ± 3.7% in air vs. 10.4 ± 2.7% in oxygen, P = 0.0201) were observed to accompany oxygen challenge. Correlations between f and α during both air and oxygen breathing were found; the correlation coefficients ( r ) were −0.90 and −0.96, respectively. Positive correlations between Dt and DDC with oxygen breathing ( r = 0.95, P = 0.0003), f and DDC with air breathing were also observed ( r = 0.95, P = 0.0004). Conclusion Quantitative diffusion MRI demonstrated changes in tumor perfusion in response to oxygen challenge. J. Magn. Reson. Imaging 2015;42:1450–1457.