The aim of the present study was to quantify both perfusion and extravasation in the prostate to discriminate tumor from healthy
tissue, which might be achieved by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a nonspecific low-molecular-weight
contrast medium (CM). To determine extravasation as well as tissue perfusion an inversion-prepared dual-contrast sequence
employing a parallel acquisition technique (PAT) was designed for interleaved acquisition of
T
1-weighted images for extravasation measurement and
T2
T*2 T^{\ast}_{2} -weighted images for determination of the highly concentrated bolus with a sufficiently high temporal and spatial resolution
at an acceptable signal-to-noise ratio. Thirteen patients with proven prostate cancer were examined with the sequence using
a combined body-array prostate coil. Before pharmacokinetic evaluation the images were intensity-corrected and, if required,
motion-corrected. The pharmacokinetic model used to calculate perfusion, permeability, blood volume, interstitial volume,
transit time, and vessel size index included two compartments and a correction of delay and dispersion of the arterial input
function. The information provided by the dual-contrast sequence allowed application of a more elaborate model for evaluation
and enabled quantification of all parameters. Peripheral prostate tumors were found to differ from peripheral healthy prostate
tissue in perfusion (1.38 mL/(min cm
3) vs. 0.23 mL/(min cm
3),
p = 0.004), mean transit time (2.88 vs. 4.88 s,
p = 0.039), and blood volume (1.9 vs. 0.7%,
p = 0.019). A inversion-prepared dual-contrast sequence acquiring
T
1- and
T*2 T^{\ast}_{2} -weighted images with sufficient temporal resolution and signal-to-noise ratio was successfully applied in patients with prostate
cancer to quantify all pharmacokinetic parameters of inflow and extravasation of a low-molecular-weight inert tracer.
Keywords Dynamic contrast-enhanced magnetic resonance imaging - Perfusion - Permeability - Dual contrast - Prostate