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On the correlation between the water diffusion coefficient and oxygen tension in RIF‐1 tumors
Author(s) -
Helmer Karl G.,
Han Sam,
Sotak Christopher H.
Publication year - 1998
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199805)11:3<120::aid-nbm506>3.0.co;2-#
Subject(s) - carbogen , correlation coefficient , effective diffusion coefficient , diffusion , chemistry , breathing , nuclear magnetic resonance , analytical chemistry (journal) , oxygen , nuclear medicine , biomedical engineering , magnetic resonance imaging , anatomy , chromatography , thermodynamics , medicine , mathematics , physics , statistics , organic chemistry , radiology
Water diffusion‐coefficient mapping was used in conjunction with 19 F inversion‐recovery echo‐planar imaging (IR‐EPI) of a sequestered perfluorocarbon (PFC) emulsion to investigate the spatial correlation between the diffusion coefficient of water and the tissue oxygen tension (pO 2 ) in radiation‐induced fibrosarcoma (RIF‐1) tumors ( n = 11). The diffusion‐time‐dependent apparent diffusion coefficient, D(t) , was determined by acquiring diffusion coefficient maps at 20 different diffusion times. Maps at four representative time points in different regions of the D(t) curve were selected for final analysis. An intravenously administered PFC emulsion, perfluoro‐15‐crown‐5‐ether, was used to generate the pO 2 maps. D(t) and pO 2 data were acquired with the animal breathing either air or carbogen (95% O 2 – 5% CO 2 ) to investigate the effects of increased tumor pO 2 on D(t) . The average increase in tumor pO 2 was 22 torr when the breathing gas was changed from air to carbogen. Correlation plots generated from pixel data for D(t) (air breathing) vs D(t) (carbogen breathing) show little deviation from a slope of unity. Correlation plots of D(t) vs pO 2 indicate that no correlation is present between these two parameters. This study also confirmed that necrotic tissue was best differentiated from viable tumor tissue based on D(t) maps at long diffusion times. © 1998 John Wiley & Sons, Ltd.