Usefulness of pulmonary vascular leakiness assessment in interstitial pneumonitis

Study objective: Pulmonary vascular leakiness of Ga-67-circulating transfer rin in interstitial pneumonitis (IP) was estimated by our previously descri bed method, and its ability to evaluate disease activity was compared with conventional Ga-67 scintigraphy Design: Using 30-min dynamic scanning data after IV injection of 67Ga citra te, the exponential equilibration coefficient of Ga-67 between the intravas cular and pulmonary interstitial compartments was calculated and defined as the leak index (LI). Pulmonary Ga-67 uptake mas assessed by gallium index, determined by conventional static images taken 48 h after Ga citrate injec tion. Setting: Hospitalized patients. Participants: The study population consisted of 17 control patients and 20 patients with IP. Results: The mean LI in patients with IP was significantly higher than in t he control group (p < 0.0001), whereas no significant increase in gallium i ndex was noted between the IP group and the control group. No significant c orrelation was found between gallium index and LI among all study participa nts. Mean LI in patients with active IP was significantly higher than in pa tients with stable IP (p = 0.0024). Conclusions: An increase in pulmonary vascular leakiness was found in patie nts with IP. LI may be useful to assess the disease activity.