An automated quantitative analysis of ventilation-perfusion lung scintigrams.

We have devised an automated computer analysis of ventilation (Kr-8 1m) and perfusion (Tc-99m) lung images that produces a graphical image of the distribution of ventilation and perfusion, and of ventilation-perfusion ratios. The analysis has overcome the following problems: the identification of the midline between two lungs and the lung boundaries, the exclusion of extrapulmonary radioactivity, the superimposition of lung images of different sizes, and the format for presentation of the data. Therefore, lung images of different sizes and shapes may be compared with each other. The analysis has been used to develop normal ranges from 55 volunteers. Comparison of younger and older age groups of men and women show small but significant differences in the distribution of ventilation and perfusion, but no differences in ventilation-perfusion ratios. Examples are presented to demonstrate that the technique can discriminate between normal and abnormal scintigrams. The analysis of serial images from one individual shows high reproducibility.