Analysis of scintigraphical lung images before and after treatment of horses suffering from chronic pulmonary disease

Scintigraphical analysis of the ratio of inhalation (i) to perfusion (Q) was designed to determine whether chronic pulmonary disease in horses induced mismatches in i/Q and to assess whether medical treatment would restore an I/Q distribution pattern identical to that of control horses. In addition, the results of the I/Q analysis were correlated with the alveolar‐arterial PO 2 difference (AaDO 2 ). The I/Q matching found in a group of control horses was compared with the I/Q analysis of a group of diseased horses before and after their clinical signs had been treated. The analysis indicated that there was mismatching between I and Q before they were treated. The treatment improved the diseased horses, pulmonary function but there was still heterogeneity in the I/Q distribution after they had been treated. The i/Q analysis parameters were well correlated with the ratio of ventilation (V A ) and pulmonary blood flow (Q), evaluated by the determination of AaDO 2 .