Role of advanced magnetic resonance imaging in the assessment of malignancies of the mediastinum

Table 2 Perfusion weighted imaging derived parameters

Semiquantitative parameters
Initial area under the curve	Include information of blood flow, blood volume, permeability, extravascular–extracellular space volume and microvessel density.
Time to peak	Depends on tissue perfusion
Wash in	Represents velocity of enhancement
Wash out	Represents velocity of enhancement loss
Quantitative parameters
Ktrans	Influx volume transfer constant of a contrast agent from the vascular compartment to the interstitial space
Ve	Volume of extravascular–extracellular space per unit of tumor volume
Vp	Blood plasma volume
Kep	Rate constant between extravascular-extracelular space and plasma