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Dynamic Gd‐DTPA enhanced MRI as a surrogate marker of angiogenesis in tissue‐engineered bladder constructs: A feasibility study in rabbits
Author(s) -
Cheng HaiLing Margaret,
Chen Jun,
Babyn Paul S.,
Farhat Walid A.
Publication year - 2005
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.20278
Subject(s) - angiogenesis , cd31 , magnetic resonance imaging , vascular endothelial growth factor , vascularity , medicine , dynamic contrast enhanced mri , vascular permeability , microvessel , in vivo , pathology , vegf receptors , nuclear medicine , urology , biology , radiology , microbiology and biotechnology
Purpose To evaluate the potential of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) to assess angiogenesis in tissue‐engineered bladder constructs in a blinded animal study, and compare different analysis approaches and their correlation with microvessel density (MVD). Materials and Methods Constructs fortified with vascular endothelial growth factor (VEGF) for enhanced vascularity were grafted onto the bladder in nine rabbits. DCE‐MRI of Gd‐DTPA uptake was performed and analyzed using Tofts' model, the area under the concentration time curve (AUC), and the uptake slope. DCE‐MRI parameters were compared to MVD determined with CD31 immunohistochemistry. Results Significantly increased MVD was found in the high VEGF group (20 ng/g of tissue) but not at low VEGF (10 ng/g) (2.3× increase, P = 0.035 vs. 1.1× over control). Enhanced permeability at low VEGF was suggested by elevated K trans , but overall correlation to MVD was poor. Significant correlation to MVD was obtained with AUC 8min ( r = 0.705, P = 0.034). Furthermore, AUC 8min provided the most precise discrimination between different VEGF preparations and was the only parameter to show a significant increase ( P = 0.0058) consistent with MVD changes at high VEGF. Conclusion Findings support DCE‐MRI for evaluating angiogenesis in bladder constructs and suggest vessel changes other than density. Future studies should incorporate larger contrast agents and permeability assessment to devise an optimal DCE‐MRI strategy. J. Magn. Reson. Imaging 2005;21:415–423. © 2005 Wiley‐Liss, Inc.