• Hai-Ling Margaret Cheng, Jun Chen, Paul S Babyn, and Walid A Farhat.
• Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada. hai-ling.cheng@sickkids.ca
• J Magn Reson Imaging. 2005 Apr 1; 21 (4): 415-23.

PurposeTo 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 MethodsConstructs 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.ResultsSignificantly increased MVD was found in the high VEGF group (20 ng/g of tissue) but not at low VEGF (10 ng/g) (2.3x increase, P = 0.035 vs. 1.1x 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.ConclusionFindings 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.Copyright 2005 Wiley-Liss, Inc.

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