Cardiac Flow from Acetate PET

Van den Hoff et al. [46] have investigated and validated ¹¹C-acetate as a flow tracer. This methodology is implemented as the Card Acetate (1 Compartment) model. It employs a single tissue compartment model

with tracer exchange between arterial plasma C_a and myocardial tissue C_myo and a differential equation

A metabolite correction is necessary to derive the plasma activity from whole blood measured in the left cavity.

with T_1/2=5.3 min. K₁ is the product of flow F and extraction E which is flow dependent for acetate. The relation found [46] is described by the following relation

Additionally, the model incorporates a cardiac dual spillover correction by the operational equation

where
V_lv = spill-over fraction of the blood activity in the left ventricle C_lv(t),
V_rv = spill-over fraction of the blood activity in the right ventricle C_rv(t) .

Implementation Notes:

• 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) corrected by the metabolite buildup it serves as the input curve, (2) it is used for spillover correction of all myocardial TACs. It must be loaded as the Input curve.
• The spill-over fraction from the right ventricle V_rv is automatically fixed to zero if the string "Sep" is not contained in the name a region. 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 V_rv = 0 in all regional models proceed as follows: in one region, set V_rv =0 and disable the fit checkbox; fit the region; configure the button below Copy to all regions to Model and Par. and activate it.