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Correlative dynamic contrast MRI and microscopic assessments of tumor vascularity in RIP‐tag2 transgenic mice
Author(s) -
Sennino Barbara,
Raatschen HansJuergen,
Wendland Michael F.,
Fu Yanjun,
You WeonKyoo,
Shames David M.,
McDonald Donald M.,
Brasch Robert C.
Publication year - 2009
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.22040
Subject(s) - vascularity , vascular permeability , magnetic resonance imaging , dynamic contrast enhanced mri , chemistry , pathology , extravasation , nuclear medicine , nuclear magnetic resonance , medicine , radiology , physics
The purpose of this study was to define the feasibility of dynamic contrast‐enhanced magnetic resonance imaging (MRI) to estimate the vascular density and leakiness of spontaneous islet cell tumors in RIP‐Tag2 transgenic mice. Dynamic T 1 ‐weighted spoiled gradient echo (SPGR) imaging at 2.0 T was performed in 17 RIP‐Tag2 mice using a prototype blood pool macromolecular contrast medium (MMCM), albumin‐(Gd‐DTPA) 35 . Kinetic analysis of the dynamic enhancement responses based on a two‐compartment model was used to estimate fractional plasma volume (fPV) and the coefficient of endothelial permeability (K PS ) for each tumor. The MRI estimate of fPV was correlated on a tumor‐by‐tumor basis with corresponding microscopic measurements of vascular density. The fPV assays by MMCM‐enhanced imaging ranged from 2.4%–14.1% of tissue volume. Individual tumor fPV values correlated significantly ( r = 0.79, P < 0.001) with the corresponding microscopic estimates of vascularity consisting of the combined area densities of lectin‐perfused microvessels plus erythrocyte‐stained blood lakes. A biotinylated derivative of the albumin‐based MMCM confirmed extravasation of the contrast agent from some tumor blood vessels and accumulation in 25% of blood lakes. The K PS values ranged from 0 (no detectable leak) to 0.356 mL/min/100 cm 3 . Dynamic MMCM‐enhanced MRI is feasible in RIP‐Tag2 pancreatic tumors, yielding estimates of vascular permeability and microscopically validated measurements of vascular richness. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.