Table 1.

Summary of parameters used to derive the indicator-dilution theory and to define clinically relevant tissue perfusion quantities.

Variable	Unit	Description
V voi	mL	Total volume under consideration
V cap	mL	Volume of the capillary bed within the volume V voi
V voi*	mL	Volume V voi without the volume of the capillary bed,  V voi* = V voi − V cap
ρ voi	g/mL	Mean density of the volume V voi
ρ voi*	g/mL	Mean density of the volume V voi*
m c,voi(t)	g	Total mass of contrast agent in volume V voi
c art(t)	g/mL	Local contrast agent concentration at the arterial inlet, c art(t) = dm/dV|t, measured at the arterial inlet
c ven(t)	g/mL	Local contrast agent concentration at the venous outlet,  c ven(t) = dm/dV|t, measured at the venous outlet
c voi(t)	g/mL	Average contrast agent concentration in the total volume V voi,  c voi(t) = m c,voi(t)/V voi
c cap(t)	g/mL	Average contrast agent concentration in the capillary bed,  c cap(t) = m c,voi(t)/V cap
c voi*(t)	g/mL	Average contrast agent concentration corresponding to V voi*, c voi*(t) = m c,voi(t)/V voi*
F	mL/s	Volume flow at the arterial inlet and at the venous outlet
h(t)	1/s	Probability density function of the transit times