Quantitative pharmacokinetic analysis of DCE-MRI data without an arterial input function: a reference region model.

Area of Science:

• Radiology and Imaging Science
• Biomedical Engineering
• Oncology Research

Background:

• Dynamic contrast-enhanced MRI (DCE-MRI) is crucial for evaluating tumor characteristics like perfusion and microvascular permeability.
• Traditional DCE-MRI analysis relies on the arterial input function (AIF), which is challenging to measure accurately, often requiring high temporal resolution.
• Accurate quantification of pharmacokinetic parameters, such as Ktrans and v(e), is essential for effective tumor assessment.

Purpose of the Study:

• To develop and validate a novel DCE-MRI analysis method that eliminates the requirement for direct arterial input function (AIF) measurement.
• To enable quantitative assessment of tissue properties using a reference region (RR) approach, simplifying DCE-MRI data analysis.
• To improve the ability to probe tumor heterogeneity by allowing for higher spatial resolution and signal-to-noise ratio (SNR) imaging.

Main Methods:

• A reference region (RR) method was developed, comparing tissue of interest (TOI) curve shapes to a reference tissue, bypassing AIF measurement.
• Literature values for Ktrans (perfusion-permeability product) and v(e) (extravascular-extracellular volume fraction) were assigned to the RR.
• Simulations were used to test the method's robustness to noise and RR parameter assignment errors, followed by application to a Lewis Lung Carcinoma mouse model.

Main Results:

• The RR method demonstrated robustness at 10% noise levels, yielding accurate (+/-20%) and precise (+/-15%) Ktrans and v(e) values.
• Application to a Lewis Lung Carcinoma model showed distinct Ktrans and v(e) values for slowly and rapidly enhancing tumor regions.
• Parametric maps revealed elevated Ktrans and v(e) values at the tumor periphery, indicating increased perfusion and permeability.

Conclusions:

• The reference region (RR) approach provides a robust and accurate method for quantitative DCE-MRI analysis without AIF measurement.
• This methodology facilitates improved assessment of tumor perfusion and permeability, enabling higher spatial resolution and SNR imaging.
• The RR method significantly enhances the capability to investigate tumor heterogeneity and provides valuable insights for cancer research.