  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.
