Related Experiment Videos
Tumor characterization with dynamic contrast-enhanced MRI using MR contrast agents of various molecular weights
1Department of Radiological Sciences, University of California, Irvine 92697-5020, USA.
Abstract:
Dynamic contrast-enhanced MR imaging was used to measure the kinetics of enhancement in three different animal tumor models (Walker 256, R3230 AC, MCF7) using three different Gd complexes (Gd-DTPA, Gd-DTPA-24-cascade-polymer 30 kD, and polylysine-Gd-DTPA 50 kD). The three tumor models varied in growth rate, with the most rapid growth demonstrated by Walker 256 cells and the slowest growth occurring in the MCF7 cells. For each tumor, the kinetics of enhancement using polylysine-Gd-DTPA was analyzed using a pharmacokinetic model to estimate the vascular volume of the tumor. The rate of entry of the contrast agent into the interstitial space served as the measure of vascular permeability. The smallest molecular-weight agent, Gd-DTPA, could not provide information about vascular permeability. The intermediate and the largest agents both demonstrated that the faster-growing Walker 256 tumor had greater vascular permeability than did the slower-growing R3230 AC tumor. The degree of vascular permeability in the MCF7 tumor could not be assessed fairly due to insufficient statistics. The current study provides evidence supporting the hypothesis that more rapidly growing tumors have higher vascular permeability than do tumors that grow more slowly.
Insights
Faster-growing tumors exhibit higher vascular permeability, as shown by dynamic contrast-enhanced MRI. Larger gadolinium (Gd) contrast agents effectively measured this permeability in animal tumor models.
Area of Science:
- Oncology
- Radiology
- Pharmacokinetics
Background:
- Tumor growth rate influences vascular characteristics.
- Understanding tumor vascular permeability is crucial for treatment efficacy.
- Dynamic contrast-enhanced MRI (DCE-MRI) is a key imaging technique.
Purpose of the Study:
- To investigate the relationship between tumor growth rate and vascular permeability using DCE-MRI.
- To evaluate the efficacy of different gadolinium (Gd) contrast agents in assessing tumor vascular permeability.
- To correlate tumor growth kinetics with vascular parameters in preclinical models.
Main Methods:
- Utilized DCE-MRI to analyze contrast agent kinetics in three distinct animal tumor models (Walker 256, R3230 AC, MCF7) with varying growth rates.
- Employed three Gd-based contrast agents: Gd-DTPA, Gd-DTPA-24-cascade-polymer (30 kD), and polylysine-Gd-DTPA (50 kD).
- Applied pharmacokinetic modeling to estimate tumor vascular volume and assess vascular permeability based on contrast agent interstitial space entry rate.
Main Results:
- The smallest contrast agent (Gd-DTPA) did not provide sufficient data for vascular permeability assessment.
- Intermediate and larger Gd agents revealed higher vascular permeability in the faster-growing Walker 256 tumor compared to the slower-growing R3230 AC tumor.
- Vascular permeability in the MCF7 tumor model could not be reliably assessed due to statistical limitations.
Conclusions:
- Supports the hypothesis that rapidly growing tumors possess greater vascular permeability than slower-growing tumors.
- Demonstrates the utility of larger Gd-based contrast agents in DCE-MRI for evaluating tumor vascular permeability.
- Highlights the potential of DCE-MRI in characterizing tumor angiogenesis and growth dynamics.