Assessment of pharmacokinetic parameters by different models in dynamic contrast-enhanced MRI of prostate

; NEX = 0.5; 2.0-mm slice thickness, contiguous slices; 26 slices, Acquisition time per volume: 24 s, 32 time points). The extracellular contrast agent Gadoteridol (ProhanceTM, Bracco Diagnostic Inc, Princeton, NJ, 0.2 mmol/kg bodyweight) was intravenously injected at a rate of 0.2 ml/s after 3 time points by a power injector (Spectris®, MedRad, Indianola, PA) followed by a 15 ml flush of saline solution injected at the same rate. These most commonly used pharmacokinetic models are based on the exchange of contrast agent between two compartments: one compartment is blood plasma space; the other compartment is extravascular extracellular space (EES). The volume transfer rate from the blood plasma to the EES is defined as transfer constant (K trans ), and the volume transfer rate from the EES to the blood plasma is defined as rate constant (kep). The general equation describing the changes of the tracer concentration in tissue is obtained as ,