Processing of Xe-127 regional pulmonary ventilation by factor analysis and compartmental modeling

A regional lung ventilation was modeled in five cases using Xe-127 during the first 3 min of wash-out. A factor analysis of the dynamic structures algorithm allowed estimation of the elementary kinetics and their respective proportions contained in time series images. Each factor was interpreted as the sampling of a compartment. It was associated to a factor image representing its spatial distribution and to a percentage of the total collected information. In the study, three factors were estimated: a fast clearance in the lower lung regions (28.9%), a slower clearance in the upper regions (33.4%), and a slow kinetics in blood and tissues containing dissolved xenon (37%). Estimates of the kinematics components obtained from a factor analysis of dynamic structures (FADSs) were used for compartmental analysis. The authors applied this method to the study of the regional ventilation distribution to establish the model and some possible variations. (FADSs) and region of interest results were used for modeling and compared