Factor Analysis (H2O, Lung TAC)

The Factor Analysis (H2O, Lung TAC) model performs a factor analysis (FA) on dynamic cardiac H₂¹⁵O PET data to obtain anatomical images of the heart. Please refer to the guide of the cardiac modeling tool PCARD for details.

Principle

One TAC must be specified which is assumed to represent H₂¹⁵O activity in the lung. The model then proceeds as follows:

During model preprocessing three TACs are mathematically derived from the Lung TAC

1. Blood activity in the right ventricle (negative time shift of lung TAC)
2. Blood activity in the left ventricle (positive time shift of lung TAC)
3. Activity in myocardium: it is calculated using a 1-tissue compartment model and pre-defined values for myocardial perfusion, partition coefficient, and the shifted lung TAC as the input curve.

During pixel-wise processing myocardium and blood pool images are calculated by a factor analyis:

• Myocardium: variate is TAC_myocardium; covariates are TAC_LV, TAC_RV
• Blood Pool: variate is TAC_lung; covariates are TAC_myocardium