Comprehensive model for simultaneous MRI determination of perfusion and permeability using a blood-pool agent in rats rhabdomyosarcoma

Abstract

To present a new compartmental analysis model developed to simultaneously measure tissue perfusion and capillary permeability in a tumor using MRI and a macromolecular contrast medium. Rhadomyosarcomas were implanted subcutaneously in 20 rats and studied by 1.5-T MRI using a fast gradient echo sequence (2D fast SPGR TR/TE/alpha 13 ms/1.2 ms/60 degrees ) after injection of a macromolecular contrast medium. The left ventricle and tumor signal intensities were converted into concentrations and modeled using compartmental analysis, yielding tumor perfusion F, distribution volume Vdistribution, volume transfer constant Ktrans, rate constant of influx kpe, and initial extraction (fraction) E. Tumor perfusion was F=43+/-29 ml.min-1.100 g-1. The permeability study allowed the measurement of kpe=0.37+/-0.12 min-1 and Ktrans=0.01+/-0.0031 min-1. The blood volume could be assimilated to the distribution volume (Vdistribution=2.9+/-1.01%) since the capillary leakage was small. The simultaneous assessment of perfusion and permeability allowed quantification of the initial extraction (fraction) E=2.34+/-1.05%. Quantification of both tumor perfusion and capillary leakage is feasible using MRI using a macromolecular blood pool agent. The method should improve tumor characterization.

Tracer kinetic analysis of dynamic contrast‐enhanced MRI and CT bladder cancer data: A preliminary comparison to assess the magnitude of water exchange effects

“…This was due to an insufficient period of data acquisition, which ended before full exchange of contrast agent between the plasma and EES had time to establish (45,46). This was also seen in three of the MR data sets.…”

Dynamic contrast-enhanced MR imaging to assess physiologic variations of myometrial perfusion

“…The molecules of contrast agent can leak through the endothelial wall of capillaries but remain extracellular. Therefore, the evolution of tissue contrast agent concentration follows the equation of a two-compartmental model (M2) with exchanges between the capillary and the interstitial spaces (see Appendix) [14][15][16]29]. In addition to tissue blood flow F (ml/min/100 ml) and blood volume fraction V b (%), this model provides the permeabilitysurface area product PS (ml/min/100 ml), the extracapillary Fig.…”

“…With this technique, exchange of a low-molecular-weight contrast medium, such as the widely used gadolinium (Gd) chelates, between the intravascular and the extravascular extracellular spaces in tissue can be evaluated. Using compartmental models of contrast kinetics agents, quantitative DCE-MRI is a powerful tool for in vivo evaluation of the microvascular properties of tissue, including tissue blood flow, tissular blood volume, vascular permeability and the extravascular extracellular volume [12][13][14][15][16].…”

Quantification of cerebral blood flow, cerebral blood volume, and blood–brain‐barrier leakage with DCE‐MRI

“…A model with the same mathematical structure has been used previously for the evaluation of animal tumor models (39,40). Solving the equations produces the following formulae for R P and R E (the equivalent of Eqs.…”