Pharmacokinetic parameters quantification in DCE-MRI for prostate cancer

Tumor vascularity detection and quantification are of high relevance in the assessment of cancer lesions not only for disease diagnostics but for therapy considerations and monitoring. The present work addressed the quantification of pharmacokinetic parameters derived from the two-compartment Brix model by analyzing and processing Dynamic Contrast-Enhanced Magnetic Resonance Images (DCE-MRI) of prostate cancer lesions. The 3D image sets were acquired at regular time intervals, covering all the phases implied in contrast injection (wash-in and wash-out phases), and the standardized image intensity is determined for each voxel, conforming to a 4D data set. Previous voxel classification was carried out by the three-time-point method proposed by Degani et al. (1997) and Furman-Haran et al. (1998) to identify regions of interest. Relevant pharmacokinetic parameters, such as kel, the vascular elimination rate, and kep, the extravascular transfer rate, are extracted by a novel interpolation method applicable to compartment models. Parameter distribution maps were obtained for either pathological or unaffected glandular regions indicating that a three-compartment model, including fast and slow exchange compartments, provides a more suitable description of the contrast kinetics. Results can be applied to prostate cancer diagnostic evaluation and therapy follow-up.