Ventilation/perfusion imaging in a rat model of airway obstruction.

The global increase in asthma, chronic obstructive pulmonary disease, and other pulmonary diseases has stimulated interest in preclinical rat models of pulmonary disease. Imaging methods for study of these models is particularly appealing since the results can be readily translated to the clinical setting. Comprehensive understanding of lung function can be achieved by performing registered pulmonary ventilation and perfusion imaging studies in the same animal. While ventilation imaging has been addressed for small animals, quantitative pulmonary perfusion imaging has not been feasible until recently, with our proposed technique for quantitative perfusion imaging using multiple contrast-agent injections and a view-sharing radial imaging technique. Here, we combine the method with registered ventilation imaging using hyperpolarized (3)He in an airway obstruction rodent model. To our knowledge, this is the first comprehensive quantitative assessment of lung function in small animals at high spatial resolution. Standard deviation of the log (V/Q) is used as a quantitative biomarker to differentiate heterogeneity between the control and treatment group. The estimated value of the biomarker lies within the normal range of values reported in the literature. The biomarker that was extracted using the imaging technique described in this work showed statistically significant differences between the control rats and those with airway obstruction.