Card. Rb-82 (1 Compartment)
The model has the standard 1-compartment form
with the differential equation
The equation assumes that the activity in the left ventricle Clv(t) is used as the input curve.
Rb is known to have a flow-dependent extraction fraction, so that K1 , which is the product of flow F times extraction fraction E, is described by the expression
The values of the correction factors reported by Lortie et al.  are
A = 0.77
B = 0.63 [ml/min/g]
The model implements a geometric double spillover correction for activity from the left and right ventricle in the form
Vlv = spill-over fraction of the blood activity in the left ventricle Clv(t),
Vrv = spill-over fraction of the blood activity in the right ventricle Crv(t) .
- The right ventricle curve is only used for spillover correction of septal TACs. It must be loaded as the Total blood curve.
- The left ventricle curve serves two purposes: (1) as the input curve, (2) it is used for spillover correction of all myocardial TACs. It must be loaded as the Input curve.
- In practice, the expression for K1 is inserted into the differential equation, so that F becomes a fit parameter, and K1 is a derived parameter.
- To allow the user to change the form of the extraction function the scale factor A and the exponent B an be entered as input parameters.
- The spill-over fraction from the right ventricle Vrv is automatically fixed to zero if the string "Sep" is not contained in the name of the regional TAC. The assumption is that such a TAC is not from septal tissue and should thus be modeled with spill-over from the left ventricle only. The reason for this automatism is usage of the model in the PCARD tool.
- To set Vrv = 0 in all regional models proceed as follows: in one region, set Vrv =0 and disable the fit checkbox; fit the region; configure the button below Copy to all regions to Model and Par. and activate it.
This model is also usable in the cardiac modeling tool PCARD.