Assessment of a rapid clearance blood pool MR contrast medium (P792) for assays of microvascular characteristics in experimental breast tumors with correlations to histopathology

Abstract

The diagnostic potential of a new rapid clearance blood pool contrast medium (P792; MW ‫؍‬ 6.47 kDa) for the MR assessment of microvessel characteristics was assessed in 42 chemicallyinduced breast tumors, with comparisons to albumin-(Gd-DTPA). Microvessel characteristics, including the transendothelial permeability (K PS ) and the fractional blood volume (fPV), were estimated by using dynamic MR data fit to a bidirectional twocompartment model. The MR-derived estimates for K PS and fPV using each contrast agent were compared, and assays using each contrast agent were correlated to the histologic tumor grade (SBR score) and the microvascular density (MVD) counts. Using P792-enhanced data, neither K PS nor fPV showed a statistically significant correlation with the tumor grade or the MVD (P > .05). Conversely, using albumin-(GdDTPA) 30

Noninvasive monitoring of radiotherapy-induced microvascular changes using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in a colorectal tumor model

“…Several authors have used P792 to characterize tumor physiology in animal models. Turetschek et al found no relation between transendothelial permeability estimated with P792 and histologic parameters (microvessel density and tumor grade) in a breast cancer model (32). In a prostate cancer model, however, P792-based DCE-MRI was successfully used to monitor changes in permeability after anti-VEGF therapy (15).…”

Improved tumor vascular function following high‐dose epidermal growth factor receptor tyrosine kinase inhibitor therapy

“…DCE-MRI was performed using a T 1 -weighted 3D gradient-echo sequence (TR ϭ 10. Quantitative analysis of albumin-(Gd-DTPA) 30 -enhanced MRI data was based on a two-compartment, unidirectional pharmacokinetic model, which assumes no reflux of the macromolecular contrast material (MMCM) from the tumor interstitium into the vascular compartment during the time course of the imaging experiment (30,31). Details regarding the pharmacokinetic analysis of the DCE-MRI data have been previously described (9).…”

Heterogeneity in the angiogenic response of a BT474 human breast cancer to a novel vascular endothelial growth factor‐receptor tyrosine kinase inhibitor: Assessment by voxel analysis of dynamic contrast‐enhanced MRI

“…A quantitative analysis of the albumin-(Gd-DTPA) 30 -enhanced imaging data was based on a two-compartment, unidirectional pharmacokinetic model (15,16):…”

“…For small molecular contrast media (SMCM) like gadopentetate, high temporal resolution is required in order to separately extract estimates of these factors from the kinetic data (13,14). With the combined use of macromolecular contrast media (MMCM) and a unidirectional two-compartment kinetic model (15,16), the fractional plasma volume and the PS-limited endothelial transfer constant can be simultaneously determined (17). The microvascular blood flow rates need not be known.…”